Cleotilde Gonzalez

Frédéric Moisan

Security under Uncertainty: Adaptive Attackers Are More Challenging to Human Defenders than Random Attackers

Keywords: defense strategies, security games, game theory, human behavior, learning

Game Theory is a common approach used to understand attacker and defender motives, strategies, and allocation of limited security resources. For example, many defense algorithms are based on game-theoretic solutions that conclude that randomization of defense actions assures unpredictability, creating difficulties for a human attacker. However, many game-theoretic solutions often rely on idealized assumptions of decision making that underplay the role of human cognition and information uncertainty. The consequence is that we know little about how effective these algorithms are against human players. Using a simplified security game, we study the type of attack strategy and the uncertainty about an attacker's strategy in a laboratory experiment where participants play the role of defenders against a simulated attacker. Our goal is to compare a human defender's behavior in three levels of uncertainty (Information Level: Certain, Risky, Uncertain) and three types of attacker's strategy (Attacker's strategy: Minimax, Random, Adaptive) in a between-subjects experimental design. Best defense performance is achieved when defenders play against a minimax and a random attack strategy compared to an adaptive strategy. Furthermore, when payoffs are certain, defenders are as efficient against random attack strategy as they are against an adaptive strategy, but when payoffs are uncertain, defenders have most difficulties defending against an adaptive attacker compared to a random attacker. We conclude that given conditions of uncertainty in many security problems, defense algorithms would be more efficient if they are adaptive to the attacker actions, taking advantage of the attacker's human inefficiencies.

INTRODUCTION

Security problems involve offensive and defensive actions across nations, institutions, and individuals. Attackers aim at stealing and getting access to assets, information, and goods while defenders allocate their limited security resources to prevent attackers from stealing their goods. In home security for example, a home owner may assign alarm systems to strategic locations of the house. Yet, attackers foreseeing the way home owners behave, may be able to find simple and unexpected ways to break into the house (i.e., thorough the front door). Defending against intelligent unauthorized intrusions in the cyber world can be even more challenging, given the hyper-dimensionality of the environment, the type of digital weapons used, the speed of operations and large number of nodes to protect against a relative high number of potential attackers [START_REF] Gonzalez | A cognitive model of dynamic cooperation with varied interdependency information[END_REF]. In this research we address a basic question of how do human defenders behave under several levels of uncertainty and various types of attack strategies.

Game theory is a common formalized way to inspire the development of defense algorithms in several security problems (e.g., [START_REF] Roy | A survey of game theory as applied to network security[END_REF][START_REF] Tambe | Security and Game Theory: Algorithms, Deployed Systems, Lessons Learned[END_REF][START_REF] Shieh | PROTECT: an application of computational game theory for the security of the ports of the United States[END_REF]. For example, Stackelberg games (i.e., strategic sequential games in which one's own strategy is reactive to one's rival's actions), are common in the design of algorithms that help allocating limited security resources, and results have been successfully applied to multiple naturalistic settings (e.g., [START_REF] Jain | Software assistants for randomized patrol planning for the LAX airport police and the federal air marshal service[END_REF][START_REF] Fang | Optimal patrol strategy for protecting moving targets with multiple mobile resources[END_REF]. Although these strategies have been mostly demonstrated in the physical world, a parallel situation occurs in the cyber world, where there is a need of protecting from electronic criminal activities. Researchers have also turned to using game theory to understand security and defense strategies in the cyber world [START_REF] Alpcan | Network Security: A Decision and Game-Theoretic Approach[END_REF][START_REF] Dutt | Cyber situation awareness modeling detection of cyber attacks with instance-based learning theory[END_REF]Gonzalez, 2013). Attacks in the cyber world (i.e., cyberattacks) use digital weapons that are often imperceptible to the human senses; they are not limited by geography and political boundaries; they require of highly sophisticated technical knowledge, and they may be highly dynamic and distributed. Thus, a defender in the cyber world may need strategies that are dynamic and adaptive to sophisticated attackers, in contrast to currently common static and non-adaptive defense algorithms (Bier and Azaiez, 2008;Abbasi et al., 2015a,b).

To build effective dynamic and adaptive defense algorithms we need to address at least two strong assumptions in the science of security games [START_REF] Nguyen | Towards a science of security games[END_REF] and behavioral game theory more generally [START_REF] Gonzalez | A cognitive model of dynamic cooperation with varied interdependency information[END_REF]: information certainty and human rationality. Current defense algorithms inspired by game theory assume that a defender has perfect information about the payoff matrix and the attacker's behaviors. They also often assume that players are perfectly rational and are able to account and process all information accurately. In a review of learning models from behavioral game theory, [START_REF] Camerer | Behavioral Game Theory: Experiments in Strategic Interaction[END_REF] concludes that most models rely on a full information assumption, and they would not be able to predict behavior in conditions where this information is not available. Similarly, most of these models make cognitively implausible assumptions, such as players being able to remember large amounts of information [START_REF] Gonzalez | A cognitive model of dynamic cooperation with varied interdependency information[END_REF].

This paper contributes to understanding how to possibly address these two challenges by learning from a laboratory experiment how human defenders deal with information uncertainty in games in which the attacker algorithm is random, conservative (i.e., minimizes losses) or adaptive (i.e., adapts to the defender's behavior), using an adversarial security game with payoff asymmetry that mimics real life interactions between a defender and an attacker. The conclusions that we draw from our study are general in nature and have applications to several security problems. We discuss the implications our results have for the design of defense algorithms against adaptive attackers under conditions of uncertainty.

An Asymmetric Cybersecurity Game, Attack Algorithms, and Information Uncertainty

Figure 1 illustrates a generic non-cooperative game with twoplayers, each of them being able to take two possible actions. In the context of cybersecurity, attacker, and defender interact in non-cooperative ways: The players have conflicting interests (one's gains correspond to the other's losses) characterized by a zero-sum property. In other words, there is no value in cooperating in such interactions because no player can win without making the other one lose. Furthermore, the game is fully strategic since any player's best move strictly depends on the other player's move.

Consider a simple strategic game where a potential attacker may either hack the defender's network (H) or do nothing (N) and a defender that may either surveil the network (S) or do nothing (N). In such a scenario, there exists some probability p (0 < p < 1) that the hack is successful despite surveillance. This means that there is a probability 1 -p that the hack has been stopped. The Appendix provides a game-theoretic analysis of this scenario and discusses the various assumptions of the outcomes from the strategic actions (x, y, and z), as well as the assumptions regarding the probability of the hacker's success (p).

Experimentally controlling for different attack strategies while investigating human defenders, is a common research approach [START_REF] Lieberman | Experimental studies of conflict in some two-person and three-person games[END_REF][START_REF] Messick | Interdependent decision strategies in zero-sum games: a computer-controlled study[END_REF][START_REF] Fox | The learning of strategies in a simple, two-person zero-sum game without saddlepoint[END_REF][START_REF] Coricelli | Strategic Interaction in Iterated Zero-Sum Games[END_REF]Shachat andSwarthout, 2004, 2012;[START_REF] Dürsch | Rage against the machines: how subjects learn to play against computers[END_REF][START_REF] Spiliopoulos | Humans versus Computer Algorithms in Repeated Mixed Strategy Games[END_REF]. In competitive scenarios, there often exist well-known simple strategies that vary in the level of rationality and level of adaptation to the defender's behavior. A Random strategy [START_REF] Fox | The learning of strategies in a simple, two-person zero-sum game without saddlepoint[END_REF]) is a fixed and static strategy consisting of choosing every option with an equal probability. Such rule is independent of the payoff matrix and the defender's behavior. A Minimax strategy implies the minimization of the possible loss of a worst case scenario [START_REF] Lieberman | Experimental studies of conflict in some two-person and three-person games[END_REF][START_REF] Messick | Interdependent decision strategies in zero-sum games: a computer-controlled study[END_REF][START_REF] Fox | The learning of strategies in a simple, two-person zero-sum game without saddlepoint[END_REF][START_REF] Shachat | Do we detect and exploit mixed strategy play by opponents?[END_REF]. When defined as a mixed strategy in a two-player zero-sum game, this principle guarantees the same expected payoff independently of the defender's choice (see Appendix). An Adaptive strategy may imply that an attacker accounts for the history of the defender's actions, estimates FIGURE 1 | Defender's payoffs in generic asymmetric security game (0 < y < x, 0 < z, 0 < p < 1). the defender's most likely move in the current round and choose a best response accordingly [START_REF] Brown | Iterative solution of games by fictitious play[END_REF][START_REF] Robinson | An iterative method of solving a game[END_REF][START_REF] Messick | Interdependent decision strategies in zero-sum games: a computer-controlled study[END_REF][START_REF] Dürsch | Rage against the machines: how subjects learn to play against computers[END_REF]. Unlike the other strategies, an Adaptive strategy takes into account the other player's past behavior to decide on the own agent's current behavior. The specific adaptive strategy that we consider in this study corresponds to the well-known fictitious play [START_REF] Brown | Iterative solution of games by fictitious play[END_REF][START_REF] Robinson | An iterative method of solving a game[END_REF].

Uncertainty regarding the attacker's actions and outcomes in repeated strategic interactions is of particular interest in cybersecurity and the lack of explicitly described information naturally leads people to rely more on their own past experience. Risky behaviors may be contrastingly different in situations where people rely on descriptions or experience to make decisions [START_REF] Hertwig | Decisions from experience and the effect of rare events in risky choice[END_REF]. This body of research suggests fundamental psychological differences in how humans make decisions under uncertainty [START_REF] Hau | The descriptionexperience gap in risky choice: the role of sample size and experienced probabilities[END_REF][START_REF] Hertwig | The description-experience gap in risky choice[END_REF]. In behavioral game theory, uncertainty effects are also of great interest [START_REF] Martin | A descriptionexperience gap in social interactions: information about interdependence and its effects on cooperation[END_REF][START_REF] Gonzalez | A cognitive model of dynamic cooperation with varied interdependency information[END_REF]. For example, [START_REF] Bereby-Meyer | The speed of learning in noisy games: partial reinforcement and the sustainability of cooperation[END_REF] have studied players' abilities to learn cooperation in a repeated PD game where the payoff descriptions were more or less noisy: in each outcome, the payoffs were presented either deterministically or probabilistically. The speed of individual learning was substantially diminished when the payoffs were noisy (nondeterministic), even though players could monitor one another's past actions perfectly. More generally, these studies show that even small changes in payoff environment can have a large effect on collective behavior. Our main general hypothesis is that introducing uncertainty in the attacker's payoffs (through the probability p) can affect the human defender's behavior in different ways depending on the attacker's strategy: uncertainty may lead defenders to follow noisier and more unpredictable behavior unless the attacker's strategy is sufficiently naive and exploitable.

METHODS

We examine the combined effects of (1) the attacker's preprogrammed strategy and (2) the level of uncertainty in the outcome description, on a defender's behavior in the asymmetric security game (Figure 1), using a 3 (Information Level: Certain, Risky, Uncertain) × 3 (Attacker's strategy: Minimax, Random, Adaptive) between-subjects experimental design.

Under Certain information, participants have complete information about all possible outcomes; they receive the game as in Figure 2A, corresponding to a certainty case of the game presented in Figure 1. For example, when the defender chose S and the potential attacker chose N, the outcome (S,N) indicates a payoff of -2 points to the defender and 2 points to the attacker.

Under Risky information (Figure 2B), participants only have partial information about possible payoffs they can obtain as the defender chooses S and the attacker selects H. Under Uncertain information (Figure 2C), participants are never informed about the actual value of probability p that determines the (S, H) consequence. In this case, participants only know that one player will win while the other will lose depending on the unknown probability p. Importantly, the games in all information conditions are theoretically equivalent in the sense that the same cells of the game carry the same expected payoffs: the value of p in Figures 2B,C is 0.35; the deterministic payoffs in the case of the (S,H) outcome from the Certain conditions correspond to the expected payoffs in the same outcome (where p = 0.35) in the two other conditions (Risky and Uncertain descriptions).

The attacker's strategy is manipulated into three algorithms: Minimax, Random, and Adaptive. In Minimax, the attacker always follows the Minimax principle by selecting H with 2 15 probability (and therefore N with 13 15 probability) in every round (see Appendix). These values derive from the payoffs in the baseline setting of Figure 2A. In this strategic game, the defender's Minimax strategy is to select S with a 2 3 probability and N with a 1 3 probability (in each round, the defender's corresponding expected payoff is -4 3 and potential attacker's corresponding expected payoff is 4

3 ). Note that this particular game allows for a clear distinction between both players' optimal and the Random strategy, which consists of a purely random choice where the attacker selects H or N with equal probability (0.5) at every round. The Adaptive algorithm is as follows: in the very first round of the game, the attacker selects H or N with equal probability (as with the Random strategy), and in all subsequent rounds, its choice is based on the defender's history of past moves (see Appendix).

In all conditions, participants are asked to repeatedly play against the same attacker strategy for 100 rounds (the participants are not informed about the exact number of rounds). At every round r > 1, participants receive feedback indicating the actual outcome in the previous round.

Participants

Nine Hundred and Twenty Seven American individuals (61% male; M age = 30.8, SD age = 9.3) were recruited through Amazon Mechanical Turk. Participants were randomly assigned to one of the 9 different conditions previously described: N(Minimax-Certain) = 107, N(Minimax-Risky) = 99, N(Minimax-Uncertain) = 101, N(Random-Certain) = 103, N(Random-Risky) = 102, N(Random-Uncertain) = 105, N(Adaptive-Certain) = 110, N(Adaptive-Risky) = 100, and N(Adaptive-Uncertain) = 100. Upon completion of the experiment, each person was paid based on their performance in the task. The average time spent to complete the task was 5 min 09 s, and the average amount of total payment was $0.88, including a fixed participation fee of $0.3. This research complied with the American Psychological Association Code of Ethics and the tenets of the Declaration of Helsinki and it was approved by the Institutional Review Board at Carnegie Mellon University. Informed consent was obtained from each participant.

Procedure

Starting with an initial capital of 200 points, participants were instructed to repeatedly play a game with an unknown preprogrammed attacker strategy, where each round would determine either a gain of extra credits or a loss of points from their capital. They were informed that the immediate outcome of each round depended on their own choice between two options (A and B), as well as on the attacker's decision. Note that the labeling of the players and their actions were different from those shown in Figure 2, in order to avoid uncovering any focal point that may bias people's behavior ("opponent" instead of "attacker, " option "A" instead of "S" or "H, " and option "B" instead of "N"). Participants were told that their income by the end of the experiment (in US dollars) would be calculated based on the value of their remaining total capital (if any) with a conversion rate of US$0.01 for every point.

Participants were not provided with any information regarding the attacker's strategy, except that the attacker was motivated to steal as many points as possible from their capital. They were provided with the payoff matrix corresponding to the experimental condition (as in Figure 2). The display of the payoff matrix was determined randomly from four combinations of actions [i.e., (A,A), (A,B), (B,A), or (B,B)] to control for possible effects of the game's display and the buttons' labels. In every round, feedback was provided about what choice each player made in the previous round together with the resulting payoffs.

RESULTS

The maximum expected final payoff for the defender was obtained when playing optimally against the Adaptive strategy (395.5 pts, see Appendix), and playing against Random (250 pts) or Minimax (66.7 pts) strategies was less beneficial. Figure 3 provides a summary of the corresponding final payoffs that participants obtained in each condition. Note that although participants did not lose money in this experiment (any final negative final payoff was simply reduced to a zero gain), the All payoffs can be compared to a reference payoff of 66.7 pts, which can be guaranteed to the defender against the Minimax strategy in every round, because the game is zero-sum. We observe in Figure 3 that this reference payoff is reached under the Minimax strategy in all uncertainty conditions. Average final payoffs from all conditions are at least as good as this reference payoff. Also, defenders' behavior appear better when the attacker's strategy is Adaptive or Random, compared to Minimax. However, the defenders' behavior is suboptimal compared to the maximum expected payoff they could have obtained against a Random and Adaptive strategy over 100 rounds.

Looking at the interaction effect between the attacker's strategy type and the level of uncertainty on the participant's final payoff, Table 1 provides evidence that those factors significantly influence people's payoffs in the game (after playing 100 rounds).

Figure 3 and Table 1 reveal 104; two sample t-test: t (169) = 4.5, p < 0.001, d = 0.64]. On the other hand, increasing uncertainty has no significant effect when playing against Random and Optimal. Moreover, when the payoffs are all known and deterministic, people are as efficient against Random as against Adaptive (M = 159 pts in Random-Certain condition, and M = 163 pts in Adaptive-Certain condition). One could even argue that people play better against Adaptive because of the slightly higher final payoff on average and the smaller standard deviation (SD = 113 in Random-Certain condition, and SD = 68 in Adaptive-Certain condition). This observation is particularly surprising because of the very different complexity in computing the best response in both of these conditions: learning to play optimally against Random (by always playing S) is easier as it is shown when risky or uncertain information is introduced.

Choice Behavior

Figure 4 shows that playing the game in the Certain condition leads to an average behavior that closely approaches the prediction of the Optimal principle (selecting S with a 2 3 probability, as shown earlier). The rate of selecting S in the Certain condition is 65% (N = 320), which is not significantly different from the theoretical Minimax solution of 66.66% [t (319) = -0.74, p = 0.46, d = 0.08].

However, participants' behavior differed significantly in the first round [F (2, 616) = 4.22, p = 0.015). Introducing some uncertainty in the (S,H) outcome leads to a significant increase in the rate of selecting S: 75% of participants (N = 301) chose S during the first round in the Risky condition, which is significantly different from the Certain condition at the 1% level [t (618) = -2.84, p = 0.005, d = 0.23]. Similarly, 72% of participants (N = 306) chose S during the first round in the Uncertain condition, which is significantly different from the Certain condition at the 5% level [t (624) = -2.03, p = 0.04, d = 0.16].

Table 2 shows the effect of the attacker's strategy. Uncertainty level has no significant effect. Results indicate a significant effect of rounds on average behavior, but the interaction between uncertainty and attacker's strategy is not significant.

Figure 5 illustrates the differences in overall average choices depending on the attacker's strategy over the 100 rounds, and also reveals different levels of heterogeneity in individual behavior across conditions. The highest proportion of selecting S is reached when playing against Random (N = 310, M = 82%, SD = 19), which is significantly higher than when playing against the Adaptive [N = 310, M = 67%, SD = 6; t (364) = 12.9, p < 0.001, d = 1.06]. Playing against Adaptive, however, leads to a more frequent selection of S than when playing against the Minimax strategy [N = 307, M = 47%, SD = 28; t (332) = 12.6, p < 0.001, d = 0.99].

Figure 6 depicts the overall effect of the number of rounds over the proportion of S choices. The main observation is that only the Random opponent's strategy leads defenders to adapt and increase their proportion of selecting S over time. In this case, participants learn to play the best response against the Random strategy (which corresponds to always selecting S). Also, average behavior drifts away from the theoretical Minimax solution (playing S with probability 0.67). Instead, when playing against the Minimax opponent strategy, we observe rather stable behavior across time. Average selection of S is above 65% in the first round and drops to 44% within the first 20 rounds before stabilizing for the remaining rounds. As a consequence, during the very first rounds, people's behavior again drifts away from the theoretical Minimax solution, but in a different direction as compared to the previous condition (playing against Random). This observation indicates that people do not learn to minimize the variance of their payoff (which consists in always playing T). Instead, they quickly become more indifferent between their options, regardless of the level of uncertainty.

Finally, when playing against Adaptive strategy, there is no learning effect. The standard deviation of the attacker's average behavior is, however, larger than in the Random condition (SD in Adaptive = 19; SD in Random = 5), suggesting that react to Adaptive strategy, but do not follow an adaptive strategy themselves (if they did, the attacker's average behavior would then converge toward the Nash equilibrium).

Switching Behavior

We analyzed the number of times that participants switch decisions from one option to the other in the course of 100 rounds. This analysis is relevant as it is possible that two individuals who share the same choice proportion of S reach that stage through different exploration strategies. As shown in in Table 3, there is a clear effect of both outcome uncertainty and the attacker's strategy on switching behavior. Furthermore, the interaction effect between the two factors is significant, as illustrated in Moreover, Table 3 shows the existence of a significant temporal effect: participants tend to switch less over time, and there is also a significant interaction between outcome uncertainty, the attacker's strategy, and time. Participants switch more over time when they play against Adaptive, whereas they switch less often over time when they play against Random or Minimax opponent's strategy. Furthermore, the switching rate over time depends on outcome uncertainty: people learn to switch more in Adaptive-Certain condition than in the Adaptive-Risky and Adaptive-Uncertain conditions, where the switching rate remains constant over time. Similarly, when playing against Random, the decreased switching rate is also different depending on outcome uncertainty: people learn to alternate slightly less in both the Random-Risky and Random-Uncertain conditions than in the Random-Certain condition. No difference is found across conditions when playing against Minimax strategy.

Subjective Randomization

A possible explanation for the increased rate of exploration over time against an Adaptive strategy and with full information may be a reflection of players' attempt to become unpredictable. Such explanation suggests that people may deliberately try to behave more randomly themselves when they play against an Adaptive strategy than when they play against other types of attackers. Intentional random behavior is difficult for humans to detect and perceive (e.g., [START_REF] Rapoport | Randomization in individual choice behavior[END_REF], and many current defense strategies rely on randomization of defense resources based on game-theoretic results [START_REF] Nguyen | Towards a science of security games[END_REF]. To test for this explanation we used a common non-parametric test for randomness to measure independent and identically distributed (i.i.d) behavior: the Wald-Wolfowitz runs test. This test relies on the number of runs found in a time series. It compares the observed number of runs of a dichotomous variable (e.g., participant's choice between S and N in the above asymmetric security game) against the expected number of runs. More (less) runs than expected indicate the existence of over (under) alternation in the time series. Figure 8 presents the proportion of participants for whom the subjective randomization is not supported in the first (left panel) and the last (right panel) 50 rounds.

In general, a majority of participants (>50%) do not exhibit subjective random behavior and the level of uncertainty has a clear influence when playing against an Adaptive strategy, particularly in the initial rounds. Higher subjective randomness is observed in Adaptive-Certain than in either Adaptive-Risky or Adaptive-Uncertain in the first 50 rounds (p < 0.001), but not in the last 50 rounds. Also, in the Certain condition, subjective randomization is more common in the first 50 rounds if playing against Adaptive (26% of participants do not exhibit i.i.d.) than when playing against Minimax (55% of participants do not exhibit i.i.d.) or Random opponent strategy (63% of participants do not exhibit i.i.d.). Together with the results in the previous section, these results suggest that when playing against an adaptive strategy, more certainty leads people to behave intentionally more randomly at first (first 50 rounds), before they uncover the benefits of regular alternations (last 50 rounds).

DISCUSSION

Perhaps the most surprising finding is that defenders behave more optimally and with less effort (switching) when confronting attackers represented by random strategies. Defenders seem to focus their attention on how to maximize their payoffs in the long run, even if it implies losses once in a while. They seem to gradually learn that the attacker's strategy is unchanging over time. These observations are interesting as they suggest that unpredictable or random strategies often used as defense mechanisms such as "moving target defense" [START_REF] Evans | Moving Target Defense: Creating Asymmetric Uncertainty for Cyber Threats[END_REF][START_REF] Zhuang | Investigating the application of moving target defenses to network security[END_REF] may not be as effective against human attackers. We also find that stochastic conservative strategies such as the Minimax attack strategy are easy to exploit by human defenders, and this is relevant because such attack strategies are commonly used to generate defense schedules in real life scenarios in Stackelberg security games [START_REF] Pita | Robust solutions to Stackelberg games: addressing bounded rationality and limited observations in human cognition[END_REF][START_REF] Pita | A robust approach to addressing human adversaries in security games[END_REF][START_REF] Yang | Improving resource allocation strategy against human adversaries in security games[END_REF]. Our results suggest however, that humans are able to learn to exploit this opponent's strategy, and that an adaptive strategy, which accounts for the opponent's dynamics of behavior, would be more efficient.

Another surprising finding suggests that a reduction of outcome uncertainty did not necessarily lead defenders to execute more optimal actions. Unlike Bereby-Meyer and Roth (2006), we found no significant effect of uncertainty on the speed of learning. Furthermore, this observation distinguishes asymmetric security games from existing games against nature (individual non-strategic decision problems) that reveal significant behavioral differences depending on whether information is descriptive or experiential [START_REF] Hau | The descriptionexperience gap in risky choice: the role of sample size and experienced probabilities[END_REF][START_REF] Hertwig | The description-experience gap in risky choice[END_REF]. Defenders learn to reach good performance when playing against a random attacker where the level of outcome uncertainty seems to have only little effect. In other words, people are no more or less efficient against a random attacker when there is no uncertainty. In contrast, under uncertainty, defenders have difficulty behaving more accurately against an adaptive attacker, and they exert more effort in their attempts. Because playing optimally against a random strategy (selecting the same fixed action at every trial) can be, in principle, more accessible than playing optimally against an adaptive strategy (regularly switching actions in a precise way), one would reasonably expect the former to be more profitable. Instead, we observe that playing against these two different attack strategies can be similarly profitable under certainty. A possible interpretation is that people are naturally more reluctant to play a very basic strategy, which can be easily exploited (e.g., always playing the same action could be easily learned by the opponent), rather than a more complex one, which appears to be more robust to protect them from any type of exploitation (e.g., dynamic behavior makes it more difficult for the opponent to anticipate one's future behavior). Finally, we find that when defenders interact with adaptive strategies and are given full information, they exert more effort to behave more intentionally in a "random manner, " as a possible attempt to be unpredictable to the attacker. This effect is particularly relevant in early interactions. Initial intentional random behavior and the following transition toward more predictable behavior may also be seen as a smooth learning exploratory strategy that helps people detect some behavioral pattern approaching actual optimal play. This may be related to a known transition from exploration to exploitation in decisions under risk [START_REF] Abbasi | Know your adversary: insights for a better adversarial behavioral model[END_REF].

In conclusion, our study provides helpful insights regarding the effects of uncertainty and attack behavior on a human defender behavior. Currently, most defense mechanisms inspired on game-theory assume complete information, and make unreasonable assumptions regarding rationality and cognitive plausibility of the defense mechanisms (Abbasi et al., 2015a,b). Our results suggest that humans' main defense vulnerability lies in their performance against adaptive attackers in conditions of uncertainty. Surprisingly, humans are able to handle random attacking behavior better than they are at handling adaptive attackers, suggesting that common randomized security algorithms might be less effective than adaptive human-inspired strategies for defense.

On a more practical ground, this study suggests the need to provide human defenders with more unambiguous information about possible outcomes. However, it is clear that such precise information can hardly be obtained in many real life security scenarios that strongly rely on uncertainty. To illustrate this, consider again the above situation involving a security analyst in charge of protecting a firm's network infrastructure that may be hacked by some unknown individual. In this case, the analyst has no way to know beforehand how likely a potential attacker is to counteract a defense action. The analyst simply ignores the payoffs that can result from tracking an individual that hacks the network: the hacker may indeed be more or less prepared to protect himself/herself from being identified. In order to improve the analyst's behavior in this case, our study suggests the help of a decision support system, which would provide an estimated deterministic value of the various payoffs for each possible outcome (such expected payoffs could simply be determined based on statistical data). This way, the human analyst would perceive the situation as if its description were fully known and would be more efficient at defending the firm's network. This study therefore suggests the need for increasing efforts in designing more and more efficient decision support systems that take into account the complexity of human behavior in such complex situations.

This work is only a first step toward a more general cybersecurity science. An obvious direction for future research relates to investigating behavior of trained analysts and hackers (e.g., experts) in more concrete security scenarios. Such analyses would undoubtedly help us uncover more sophisticated ways to help people protect themselves in the highly uncertain cyber world.

(ARL Cyber Security CRA). The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the U.S. Government.

FIGURE 2 |

 2 FIGURE 2 | Asymmetric security game in various conditions with x = z = 10, y = 2, and probability p = 0.35. (A) Shows the certain condition in which participants have complete information about all possible outcomes. (B) Shows the risky condition in which participants receive explicit probabilities of possible outcomes. (C) Shows the uncertain condition in which participants are not informed about the values of the probability p.

FIGURE 3 |

 3 FIGURE 3 | Final payoffs in each condition across 100 rounds. Initial endowment = 200 pts. The dotted lines represent the corresponding final payoff when the optimal solution is applied consistently.

  an effect of the attacker's strategy: the best final payoffs are obtained when playing against Random (N = 310, M = 156 pts, SD = 125), which are significantly better than when playing against Adaptive [N = 310, M = 132 pts, SD = 87; two sample t-test: t (552) = 2.8, p < 0.01, d = 0.22]. Playing against Adaptive is, however, still more significantly beneficial than playing against Minimax [N = 307, M = 67 pts, SD = 35; two sample t-test: t (408) = 12, p < 0.001, d = 0.98]. However, outcome uncertainty is also significant: playing in the Certain condition (N = 320, M = 129 pts, SD = 89) is significantly more profitable than playing in the Uncertain condition [N = 306, M = 105 pts, SD = 101; two sample t-test: t (606) = 3.1, p < 0.01, d = 0.25]. The interaction effects presented in Figure 3 suggest that uncertainty only has a significant effect on the overall payoff when playing against Adaptive strategy. Increasing uncertainty significantly decreases efficiency: final payoffs in the Adaptive-Certain condition (N = 110, M = 163 pts, SD = 68) are significantly better than Adaptive-Risky [N = 100, M = 124 pts, SD = 78; two sample t-test: t (198) = 3.8, p < 0.001, d = 0.53] and Adaptive-Uncertain [N = 100, M = 107 pts, SD =

FIGURE 4 |

 4 FIGURE 4 | Average initial behavior across information conditions.

FIGURE 5 |

 5 FIGURE 5 | Average selection of S action in each condition.

FIGURE 6 |

 6 FIGURE 6 | Average proportion of choice (S) over time. Each block is 10 rounds.

Figure 7 .

 7 Switching occurs more often when playing against Adaptive (N = 310, M = 36%, SD = 16) than when playing against Minimax [N = 307, M = 20%, SD = 15; t (614) = 13.06, p < 0.001, d = 1.03], which is also significantly more than when playing against Random [N = 310, M = 14%, SD = 15; t (615) = 5.38, p < 0.001, d = 1.42]. We also observe a main effect of uncertainty: switching in the Certain condition (N = 320, M = 26%, SD = 19) is higher than in the Risky condition [N = 301, M = 22%, SD = 17; t (613) = 2.64, p < 0.01, d = 0.22] and the Uncertain condition (N = 306, M = 22%, SD = 17; t (622) = 2.64, p = 0.02, d = 0.22]. These results suggest an interaction effect of the two variables (type of attacker strategy and outcome uncertainty). Indeed, when playing against Random, participants alternate significantly more (at the 5% level) under the Uncertain condition (N = 103, M = 17%, SD = 18) than under the Certain condition [N = 105, M = 12%, SD = 13; t (190.6) = 2.08, p = 0.039, d = 0.32]. On the other hand, when playing against Adaptive, participants alternate significantly less under the Uncertain condition (N = 100, M = 31%, SD = 15) than under the Certain condition [N = 110, M = 44%, SD = 14; t (201.3) = 6.12, p < 0.001, d = 0.90].

FIGURE 7 |

 7 FIGURE 7 | Average switching behavior in each condition.

FIGURE 8 |

 8 FIGURE 8 | Proportion of players not exhibiting i.i.d behavior across conditions in first and last 50 rounds (Wald-Wolfowitz runs tests, p < 0.05).

TABLE 1 |

 1 Factorial analysis of variance for final payoffs.

	Source		ANOVA tests
		Df	F	Eta-Squared
	(A) Attacker's strategy	2	82.39**	0.15
	(B) Outcome uncertainty	2	6.11*	0.01
	A × B (interaction)	4	3.44*	0.01
	Error (within groups)	918

**p < 0.001; *p < 0.01.

TABLE 2 |

 2 Factorial analysis of variance for average choice over blocks of 10 rounds.

	Source			ANOVA tests
			Df	Df error	F	Eta-Squared
	(A) Attacker's strategy	2	918	245.24**	0.21
	(B) Outcome uncertainty	2	918	0.89	< 0.01
	(C) Blocks of 10 rounds	7.43	6,820.28	9.45** †	< 0.01
	A × B (interaction)	4	918	0.93	< 0.01
	A × C (interaction)	14.86	6,820.28	14.04** †	0.01
	B × C (interaction)	18	8,262	1.42	< 0.01
	A × B × C (interaction)	36	8,262	1.00	< 0.01
	**p < 0.001;

† Greenhouse, Geisser corrected.

TABLE 3 |

 3 Factorial analysis of variance for switching behavior over blocks of 10 rounds.

	Source			ANOVA tests
			Df	Df error	F	Eta-Squared
	(A) Attacker's strategy	2	918	191.20**	0.17
	(B) Outcome uncertainty	2	918	5.06**	< 0.01
	(C) Blocks of 10 rounds	7.40	6,791.28	20.09** †	0.01
	A × B (interaction)	4	918	10.52**	0.02
	A × C (interaction)	14.80	6,791.28	16.96** †	0.02
	B × C (interaction)	18	8,262	0.76	< 0.01
	A × B × C (interaction)	29.59	6,791.28	2.01** †	< 0.01
	**p < 0.001;

† Greenhouse, Geisser corrected.

Frontiers in Psychology | www.frontiersin.org

June 2017 | Volume 8 | Article 982

FUNDING

This research is supported by the Army Research Laboratory under Cooperative Agreement Number W911NF-13-2-0045

AUTHOR CONTRIBUTIONS

FM contributed to the design of the study, the implementation of experimental protocols, data collection, data analyses, and write up of the manuscript. CG developed the idea of the study, contributed to the design and implementation of the study, and contributed to the writing of the manuscript.

SUPPLEMENTARY MATERIAL

The Supplementary Material for this article can be found online at: http://journal.frontiersin.org/article/10.3389/fpsyg. 2017.00982/full#supplementary-material

Conflict of Interest Statement:

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2017 Moisan and Gonzalez. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.


Margherita Pagani

published or not. The documents may come   L'archive ouverte pluridisciplinaire


Sergio Dario

Véronique Ancey2

• Bernard

Dario Magnani
email: semagnani@gmail.com

Véronique Ancey
email: veronique.ancey@fao.org

Bernard Hubert
email: bernard.hubert@inra.fr

Dairy Policy in Senegal: the Need to Overcome a Technical Mindset

Keywords: Dairy policy, Public policy, Development Anthropology, Pastoralism, Intensification, Technical changes, Senegal, West Africa

Since the 1970s, the import of tax-free powdered milk has presented an easy solution to the growing demand for dairy products in West Africa. Recent increases in agricultural price volatility have since contributed to a renewed interest in local milk. However, while the present situation raises issues of food security, rural development and trade policy, public policy remains overly focused on the technical dimensions of dairy development. This article presents the dairy landscape of Senegal, a major regional importer of powdered milk, by considering development dynamics in light of the interactions between technical and organizational models and livestock systems, in terms of relationships with resources and environment, knowledge and social organization. Two implications are discussed: the need for effective sectoral policy to tip the balance in favour of local milk; the need to base public action on a better understanding of, and improved support for, livestock systems in all their diversity.

Introduction

Since the 1970s, the import of tax-free powdered milk has presented an easy solution to meet the growing urban demand for dairy products in Senegal. However, increasing agricultural commodity price volatility, which has been particularly strong over the last decade (OCDE/FAO, 2017), has shown the limits of this strategy. Faced with unstable powdered milk prices and the rapid growth of urban demand, national authorities and private dairy businesses have shown a renewed interest in local milk production. The primary concerns of the authorities are over macroeconomic imbalances, rural poverty and the urban population's access to dairy products. Private businesses have sought to position themselves in these promising markets through takeovers and partnerships [START_REF] Choplin | L'industrie laitière européenne lorgne sur l'Afrique de l'ouest[END_REF]CTA Agritrade, 2014;[START_REF] Hansel | Beyond the Milking Parlour: An Analysis of European Dairy Company Involvement and Strategies towards West African Dairy Sector Development. Project "Milky Way to development[END_REF][START_REF] Orasmaa | The end of EU Milk Quotas -Implications in West Africa. Project "Milky Way to Development[END_REF]. In the last ten years, several dairy businesses have included local milk in their production in order to promote a positive business image, diversify their supply sources and generate more value-added products [START_REF] Corniaux | L'industrie laitière en Afrique de l'Ouest : Histoire, Stratégies, Perspectives[END_REF].

In Senegal, this trend has reinforced a classical "technicist" approach which seeks to drive dairy development by using animal production science to intensify production systems, notably by promoting the systematic use of feeding inputs and a genetic improvement of cattle breeds. This model entails measures that reduce interactions between livestock systems and the environment, such as the settlement of herders, fodder crop development, the stabling of dairy cows and the adoption of specialized breeds. Far from being neutral, livestock production intensification has a long and controversial history in the Sahel, where it has been at the heart of a technoscientific paradigm that has shaped interventions in pastoral development since colonial times [START_REF] Behnke | Rethinking range ecology: implications for rangeland management in Africa[END_REF][START_REF] Ellis | Stability of African pastoral ecosystems: Alternate paradigms and implications for development[END_REF][START_REF] Homewood | Ecology of African Pastoralist Societies[END_REF]Scoones, 1994).

While the technical dimensions of dairy production take center stage in public policy, the broader political and economic context, as well as the historical trends of sectoral public action, are the subject of little debate. Dairy development in Senegal has been characterized by limited, discontinuous public interventions, a disconnect between local production systems and technical models and contradictions between trade and development policies.

This article discusses the limits of a dairy development policy centered on technical issues. What are the implications of focusing on technical issues and productivity? What other political, economic and social dimensions are overlooked in this process? In what respect does this "technicist" approach constitute an obstacle to the conception and implementation of a more integrated sectoral policy?

This article comprises two parts: firstly, a synthetic overview of the historical trends in dairy development in Senegal from independence to the present day, in the broader and evolving political and economic context.

Secondly, an analysis of three case studies reflecting different dairy development models and successive forms of public action in dairy production and collection. The first case study relates to intensive dairy farms operating in the peri-urban area of the capital Dakar. The second presents the dairy basin around the secondary city of Kolda in the southern region of Casamance, where a dozen mini-dairies collect the milk produced by agro-pastoralists. The third describes a new social business model set up by an industrial dairy in the Senegal River Valley in the north of the country, which relies on both powdered and fresh milk. The dairy processes local milk collected from hundreds of pastoralists within the area surrounding the city of Richard Toll.

Historical trends in dairy development public action in Senegal

The post-independence period : the failure of state intervention and the growth of powdered milk After independence, Senegal inherited a segmented market with, on one hand, powder-based or imported dairy products for the expatriate population and, on the other, local milk and derived products historically traded locally or through mid-and long-range trade channels (Vatin, 1996: 126-130).

The first attempts at dairy industrialization in Africa, at the end of the 1960s, sought to imitate the Indian Flood model. In order to accelerate industrial development and cooperative organization, donated powdered milk was to be sold in order to finance local milk value chains, which, it was hoped, would then have gradually replaced the imports. Whereas the model played a positive role in India, where it was supported by a political commitment to autonomy and dairy development, it was a relative failure in West Africa for both local and international reasons [START_REF] Vatin | Le lait et la raison marchande. Essais de sociologie économique[END_REF]. This was particularly true in Senegal, where a state-run dairy industry (UCOLAIT), set up in Saint-Louis, operated for only four years (1968)(1969)(1970)(1971)(1972). Though local milk collection had achieved promising results (200 000 liters in 1971), major production and marketing failures, combined with bad management, led the dairy to bankruptcy (Vatin, 1996: 142-146).

In the 1970s, powdered milk imports increased sharply (from less than 50 000 t in 1973 to over 100 000 t in 1977; Duteurtre and Corniaux, 2013: 35), mainly because of demographic growth, urbanization and trade policy. In reaction to this trend, the Senegalese government implemented a seven-year dairy development project, Projet de Développement de la Production Laitière intensive et semi-intensive dans la région des Niayes (Project for intensive and semi-intensive dairy development in the Niayes region, 1982Niayes region, -1989)), in the countryside around the capital Dakar. The project, run by the Institut Sénégalais de Recherches Agricoles (Senegalese Agricultural Research Institute, ISRA), aimed to popularize new feed techniques and imported dairy breeds in order to create more intensive and specialized livestock systems. An experimental farm provided livestock feed and dairy cows, as well as zootechnical and veterinary supervision, while a cooperative was created to market milk in Dakar. The large majority of the new dairy farms did not survive after the project ended [START_REF] Mbaye | Analyse du projet de développement de la production laitière bovine intensive et semi-intensive des Niayes[END_REF], but the intensive dairy production model persisted at a small scale.

Structural adjustment and liberalization (1985-2000): the development of small-scale dairy processing

During this period of progressive state withdrawal, several innovative initiatives were launched in dairy production, collection and processing. At the beginning of the 1990s, Nestlé developed a network to collect local milk in the pastoral areas surrounding the city of Dahra, a major national livestock market. Collected milk was dried and mixed with imported powdered milk in the Nestlé plant in Dakar. The operation's model of drying expensive collected milk made little economic sense, confirming suspicions that Nestlé's main goal was to promote a positive image of the company. It set up a network of collection centers to buy milk from hundreds of pastoralists. However, the quantities collected were generally low (82 000 liters in 1991 and 17 000 liters in 1992, which was a drier year) and accounted for only 1 per cent of the factory's annual supply (Vatin, 1996: 168-169). Several factors explain the problems that Nestlé faced in collecting local milk: prices were higher in local informal markets, milk is a major source of nutrition for the calves, and the women controlling milk management sought to valorize both curdled milk and butter. The project ended in 2002 when Nestlé moved its factory abroad.

In the mid-1990s, an alternative dairy processing pattern gained prominence in West Africa. With the support of the Food and Agriculture Organization of the United Nations (FAO) and non-governmental organizations, the number of mini-dairies processing local milk increased sharply (21 mini-dairies were operating in Senegal in 2000, 56 in 2010; Duteurtre and Corniaux, 2013: 33). Generally established in secondary cities, mini-dairies use basic equipment to collect and process small quantities of milk (from several tens to several hundreds of liters per day) to meet an urban demand for artisanal dairy products. [START_REF] Corniaux | Les minilaiteries comme modèle d'organisation des filières laitières en Afrique de l'Ouest : succès et limites. [Mini-dairies as a Model of Organization of Dairy Value-chains in West Africa: Successes and Limits[END_REF] identify the strengths but also the limits of such structures. Among their strong points, the authors mention local contracting with herders, and the provision of feed and veterinary inputs, sometimes on credit. Weaknesses include rapid saturation of local markets, supply difficulties during the dry season, and a minimal impact on national economies. In Senegal, the development of mini-dairies began with an innovative experiment in Casamance around the city of Kolda. From the middle of the 1980s, a public cotton company, Société de Développement des Fibres Textiles (Society for the Development of Textile Fibers, SODEFITEX), partnered with the ISRA to set up an incentive scheme for dairy production. This included the provision of subsidized livestock feed (cottonseed) on credit, as well as technical and veterinary support. From the beginning of the 1990s, the partnership was extended to include a French non-governmental organization Vétérinaires Sans Frontières (Veterinarians without Borders, VSF) which provided grants and technical assistance for the creation of a network of mini-dairies.

Depicted as a success story in the 1990s, this initiative faced a crisis in the mid-2000s because of radical changes to the incentive scheme. Nevertheless, the dairy basin survived and a good dozen mini-dairies still collect local milk today.

At the end of the 1990s, the liberalization of trade between the West African Economic and Monetary Union (UEMOA) and external markets was implemented through a common tariff system for imports, enforced since 2000. This agreement established four tax rate thresholds: 0, 5, 10 and 20 per cent. Powdered milk was classed with raw materials and essential items and placed in the second threshold (5 per cent). As [START_REF] Duteurtre | Lait des pauvres, lait des riches : réflexion sur l'inégalité des règles du commerce international[END_REF] points out, common external tariffs were established before a common agricultural policy was developed. The extremely low tariffs for powdered milk imports reflected a political commitment in favour of the growing industrial processing sector and urban access to cheap products, at the expense of the coherence of sectoral development policies.

Recent trends (2000-): a growing dynamic of "technicization" in dairy development public policy

In 2000, the election of the liberal Abdoulaye Wade marked the beginning of a new phase in agricultural development policies. While the president claimed to use his strong executive power as a major driver of change, he promoted a liberal approach characterized by weak public intervention and delegation to the private sector.

Between 2000 and 2005, Senegalese dairy imports grew from 23 to 42 billion CFA francs 2 [START_REF] Duteurtre | Lait des pauvres, lait des riches : réflexion sur l'inégalité des règles du commerce international[END_REF]. In 2007/2008 an agricultural commodity price crisis demonstrated the dangers of this trend. Dairy prices increased sharply (imports grew to 83 billion CFA francs in 2013; [START_REF] Duteurtre | Etude relative à la formulation d'un Plan d'actions détaillé de développement de la filière lait au sein de l'UEMOA[END_REF], raising concerns about macroeconomic imbalances and urban consumers' access to dairy products. Rather than use this as an opportunity to reexamine patterns of dairy development, the government remained ambivalent. On one hand, a set of contingency measures were taken including tax exemptions for powdered milk imports and price controls. On the other, a program to improve national dairy production was devised by the government in 2008, which combined classical technical elements (fodder crops, imports of dairy breeds, artificial insemination) with trade-related measures such as tax exemptions for production factors and the processing of local milk, as well as controls over the export of agricultural byproducts. However, the program was not funded and the more political propositions were not enacted. Only artificial insemination was effectively financed, and from 2008 to 2013 ran as an autonomous program of genetic improvement (Programme Spécial d'Insémination Artificielle - Special Program of Artificial Insemination). The government presented this technical option as the best way to rapidly increase national milk production and reduce imports. The program also became a showcase for the presidential commitment to modernity and it clearly testifies to a growing "technicist" attitude in dairy development (Magnani, 2016: 143-158).

Since the 2000s, the dairy industry has experienced growth in the West African Sahel, where several dairy companies have started to collect local milk 3 [START_REF] Duteurtre | Commerce et développement de l'élevage laitier en Afrique de l'Ouest -une synthèse. [Trade and Development of Dairy Farming in West Africa -An Overview[END_REF]. A common trend towards mixing locally collected fresh milk and imported powdered milk emerged, which can be analysed as a new syncretic industrial 2 The common currency in the UEMOA, 656 CFA francs = 1 Euro.

3 Eight companies are collecting local milk today: Eurolait and Mali-Lait (Mali), Kirène and Laiterie du Berger (Senegal), Tiviski (Mauritania), Solani and Niger-Lait (Niger), Fada N'Gourma (Burkina Faso).

model [START_REF] Corniaux | Lait en poudre importé versus production locale en Afrique de l'Ouest: vers un nouveau modèle industriel? [Powdered milk Versus Local Dairy Production in West Africa: Towards a New Industrial Model?[END_REF]. This allowed dairies to diversify their output and introduce higher value products (cream, cheese), and to more successfully manage the strong seasonal variability of local milk production. In Senegal, Laiterie du Berger (Shepherd's Dairy) opened its dairy plant in 2006 in Richard Toll and started to process milk collected from hundreds of pastoralists living in the hinterland of the Senegal River valley. In 2009, the dairy partnered with danone.communities, the foundation established by Danone multinational group, and started operating as a social business project.

The dairy landscape in Senegal shows signs of dynamism. Between 2000 and 2016 national production grew from 119 to 226 million liters, with 61% of output coming from pastoral and agropastoral systems, compared to an estimated demand of 457.5 million liters (Goudiaby and Broutin, 2018: 17-19). About thirty intensive dairy farms still operate around Dakar along with many others around the country's secondary cities. While the small-scale processing sector seems to be stable and even growing slightly in some regions (e.g. around Dahra and Linguère) (Seck and al. 2016: 9), dairy industrial processing has grown to include about fifteen companies. Among them, only two include local milk in their production: Laiterie du Berger and Siagro (Goudiaby and Broutin, 2018: 32). This dynamism reflects the significant gap between supply and demand which makes Senegal the fourth largest importer in Sub-Saharan Africa, excluding Sudan (Seck and al. 2016: 5).

While particularly evident in Senegal, this trend more broadly reflects the growing interest of multinational dairy groups in West African markets. While some companies have been present for decades (e.g. Nestlé, Lactalis), since the 2000s and in particular the 2010s, several other major dairy groups (Glanbia, Sodiaal, Danone, Friesland-Campina, Arla) have started joint ventures and made investments in West Africa [START_REF] Choplin | L'industrie laitière européenne lorgne sur l'Afrique de l'ouest[END_REF][START_REF] Hansel | Beyond the Milking Parlour: An Analysis of European Dairy Company Involvement and Strategies towards West African Dairy Sector Development. Project "Milky Way to development[END_REF][START_REF] Orasmaa | The end of EU Milk Quotas -Implications in West Africa. Project "Milky Way to Development[END_REF]. A number of key factors explain this tendency, including the regional gap between increasing dairy consumption and a stagnating supply, and the end of the European Union milk quota (2015),4 which saw dairy groups renew their search for new markets (CTA Agritrade, 2013[START_REF] Binet | Le rôle des entreprises et des fondations privées dans la gouvernance mondiale agricole et alimentaire. [The Role of Private Businesses and Foundations in the Global Governance of Agriculture and Food[END_REF]. While the large majority of these initiatives rely on the processing or repackaging of imported powdered milk, many dairies have shown a willingness to include local milk in their supply chains, often as part of a social businesses or their corporate social responsibility [START_REF] Corniaux | L'industrie laitière en Afrique de l'Ouest : Histoire, Stratégies, Perspectives[END_REF]. Several reasons can explain this trend: a desire to promote a positive image of the role that business plays in agricultural development [START_REF] Binet | Le rôle des entreprises et des fondations privées dans la gouvernance mondiale agricole et alimentaire. [The Role of Private Businesses and Foundations in the Global Governance of Agriculture and Food[END_REF], the diversification of supply sources, a move to more value-added products, and responses to governmental directives, as in the case of Friesland-Campina investments in Nigeria. In this sense, the current situation seems ambiguous with, on one hand, more opportunities for the industrial collection of local milk and, on the other, a trend of growing powdered milk imports fostered by a favorable tax system and increasing urban demand. While there is significant scope to expand local milk collection (60 dairies could potentially start processing local milk; Orasmaa et al., 2016: 29), a new boom in powdered milk imports risks not only discouraging local milk collection as well as national and regional dairy policy implementation, but also increasing competition with local dairy products, notably in secondary cities (Broutin and al. 2018;[START_REF] Hansel | Beyond the Milking Parlour: An Analysis of European Dairy Company Involvement and Strategies towards West African Dairy Sector Development. Project "Milky Way to development[END_REF][START_REF] Orasmaa | The end of EU Milk Quotas -Implications in West Africa. Project "Milky Way to Development[END_REF].

Within this context, national and regional dairy policy frameworks have a decisive role to play. However, the trajectory of dairy policy in Senegal reveals the extent of the challenge. As noted by Seck et al. (2016: 24), there has never been a structured dairy policy in the country. At present, dairy development appears to be a secondary goal in the livestock policy framework, namely the National Program for Livestock Development, which has a strong technical focus on animal health and genetics and aims to create 'modern' livestock farms with stabling of dairy cows. In the following section, we will show why acting only along technical lines is a reductive response to the challenges faced.

Case studies analysis: patterns of dairy development and public action at work in Senegal

Dairy farming around Dakar: the failure of an industrial model disconnected from the processing sector

Beginning in the mid-1970s, Senegalese public research on livestock development identified intensification and specialization of livestock systems in dairy production as ways to meet growing urban demand for dairy products [START_REF] Denis | Promotion laitière chez les Paysans du Cap-Vert. [Dairy Promotion among the Farmers of Cape Verde[END_REF]. Two main drivers of intensification were highlighted: bovine genetics and livestock feed. A set of experiments were carried out to test exotic breeds' adaptation and performance, with encouraging results [START_REF] Ba Diao | Les systèmes d'élevage dans la Région des Niayes du Sénégal. II L'élevage laitier intensif[END_REF]. A balanced food ration using local resources was developed in the Sangalkam experimental farm and tested in the countryside. After this exploratory phase (1977)(1978)(1979)(1980)(1981)(1982), a seven-year development project (Project for intensive and semi-intensive dairy development in the Niayes region) was implemented in the peri-urban area of Dakar (1982Dakar ( -1989)). Several hundred imported Montbéliarde and Pakistani cows were delivered to 55 herders who also benefited from a range of services: subsidized animal feeds, technical and veterinary support, and artificial insemination. Despite these facilities, the project was a failure: due to the cows' mortality rate and the high production costs, 45 out of 55 farms collapsed within ten years. Researchers acknowledged that the model was ill-adapted to local livestock systems and economically unsustainable (Ba Diao, 2005: 98-105). Although the results were not positive, they could have been drawn on to devise new directions and long-term strategies. Instead, the project's failure put a definite end to public interventions in dairy development in the peri-urban area of Dakar.

Nevertheless, since the beginning of the 1990s, a few local businessmen have adopted the intensive livestock model (cow housing, imported specialized breeds fed with ensiled corn and industrial feeds) to build up largescale dairy farms. Three structures of this kind were still operating during our fieldwork. The socio-economic status and the origin of the owners had a strong impact on the trajectory of the farms. One owner was an important businessman operating in the oil trade. The other two were big import traders who had grown up in rural areas. These owners were largely motivated by the prestige of running a modern dairy business on a large scale (from 200 to 800 hundred cows) with exotic breeds (Holstein, Jersey, Normande and Girolando). But these features also contributed to the economic unsustainability of the projects. Significant investments in infrastructure were required because of the farms' size, while the management of large herds presented difficulties in terms of animal feeding, health and reproduction. A lack of access to land and available water limited the production of forage crops, encouraging the use of expensive concentrated feeds 5 . Exotic breeds were sensitive to diseases and poor habitat conditions, particularly during the wet season. As a result of these difficulties, at best only a third of the "productive" herds were lactating dairy cows. Production costs of milk (approximately 350 CFA francs on average per liter) were thus high, discouraging industrial processors from including it in their supply6 . Raw and curdled milk were sold through a network of hundreds of independent sellers who bought only a few tens of liters each and were therefore unable to absorb the total daily production of a farm (from 700 min. to 3000 liters max. per day depending on the season and the farm). In order to valorize their surplus output, farmers had to invest in expensive infrastructure to cool and process milk for sale on the formal urban market, where farm fresh curdled milk and yogurts were in direct competition with the cheaper powdered milk products. As a result, the processing experiment was a major failure that reinforced the farms' dependence on the unconditional economic support of their wealthy owners.

In the 2000s, a pool of smaller farms (10 to 50 dairy cows) emerged in the countryside around Dakar. During our fieldwork we monitored six of these structures to compare their performance, technical models and social organization. The social profiles of owners were diverse (three traders, a veterinarian, an army colonel) but only one, a French herder, had relevant experience in dairy farming. They were generally cautious towards investment compared to the owners of the large farms. Small farms needed less capital for infrastructure and their low quantities of milk (from 100 min. to 500 liters max. per day depending on the season and the farm) were easier to sell directly on farms or in local shops. However, these small farms faced the same challenges in terms of high production costs and a lack of access to land and water. As a result, only two of the six farms were able to make a profit (Magnani, 2016: 191). These two farms shared several characteristics. Firstly, they had good access to profitable niche markets: one was selling dairy products on demand to a network of expatriate clients, the other commercialized different products (fruit, eggs, chicken, fresh and curdled milk) in a grocery in Dakar. Secondly, they opted for small herds of around fifteen Holstein cows acclimated over generations. Thirdly, the owners were working full-time on the farm and brought knowledge and pragmatism.

Cows were allowed to graze on small pastures in order to keep the stables clean and improve habitat conditions. The cows' health was closely monitored.

In conclusion, the dairy livestock systems studied around Dakar were 'intensive' in inputs, capital and workload but most of them seemed to lack a sustainable economic model, partly because of the social origins of the investors. But the economic climate was also particularly difficult: a lack of integration with the processing sector; high input prices; limited access to land in the face of uncontrolled urbanization; strong competition from powdered milk. In such conditions, intensive systems needed a high level of technical support and connections to niche markets to survive.

The dairy basin of Kolda: the successes and crises of a development model based on agriculturelivestock integration

The dairy basin around the city of Kolda in southern Senegal was created at the beginning of the 1990s, through a partnership between a public cotton industry (SODEFITEX) and the Senegalese Agricultural Research (ISRA). SODEFITEX saw dairy development as a way to increase farmers' incomes and encourage them to grow cotton. The technical reference was the integration of agriculture and cattle herding, in a region with one of Senegal's largest cattle populations (599 000 head as of 2007) 7 . This model relied on the local breed Ndama, a poor dairy but trypanotolerant breed, well adapted to the local sub-humid climate. Grants were allocated to Fulani agro-pastoralists 8 to build cattle barns to house milking cows during the dry season. A range of attractive services were also provided to sustain dairy production: subsidized cottonseed 9 as supplementary feed and credit from SODEFITEX; technical and veterinarian support from research and development public services.

With the support of these measures, the number of dairy barns grew quickly to 1 000 in 1992 (Fall and Faye, 1992: 7). In order to process the increasing volume of milk produced, a non-governmental organization, Veterinarians without borders (VSF), funded the creation of a mini-dairy processing sector (five mini-dairies were operating in 2000). Progressively, the dairy sector grew to include producers, processors, private collectors and service providers working within a radius of 25 km around Kolda.

At the end of the 1990s, the public action scheme for dairy development was fundamentally reorganized.

SODEFITEX gave up its role as financial backer and was replaced by the Swiss Cooperation, which created a Service Center in partnership with the ISRA in research and innovation, and with SODEFITEX and VSF in 7 Source: Senegalese National Agency of Statistical and Demographic Data. 8 In the region most of the rural population engage in crop and livestock farming, though practices vary depending on their socio-cultural identity and the history of their social groups, which influence land tenure dynamics and economic activities. 9 Cottonseed was initially given free of charge. A price was fixed at 15 CFA francs per kilo in 1992 and increased to 50 CFA francs in 1996.

offering support to livestock farmers and dairy processors. The aim was to provide services on demand to herders and to the dairy processors, who would progressively assume the costs. Researchers attested to the profitability of dairy production at this time [START_REF] Dieye | La production laitière périurbaine au sud du Sénégal. Saisonnalité de l'offre et performances économiques[END_REF] and eight mini-dairies processed 208 105 liters of local milk, a record quantity, in 2004 [START_REF] Faye | Développer des synergies entre les services agricoles pour promouvoir la transformation des agricultures familiales : L'expérience du Pôle de Services au Sud-Est du Sénégal[END_REF]. Up to 2005, the Kolda dairy basin was considered a successful experiment based on the improvement of cattle feed through a combination of protein supplements (cottonseed) and local agricultural residues and natural pastures. However the following years saw radical change that led to the Service Center being closed and the dairy basin facing a major crisis. The main factor was the privatization of the cotton company in 2003, following which the interest-free loan scheme for cottonseed was abolished in 2005, leading to milk shortages in the dairy basin. At the same time, SODEFITEX unilaterally started to collect milk in more distant areas and to sell it to Kolda mini-dairies to make up for shortfalls in supply. This produced tensions both between herders and mini-dairies, and between SODEFITEX and its partners in the service center. The partnership was thus ended in 2006 and Swiss development funds were cut. The subsequent phase of the project, which should have seen the transfer of the incentive scheme to local professional organizations, was never implemented. Finally, in 2007, SODEFITEX sharply increased cottonseed prices from 50 to 122 CFA francs per kilo. As a result of all these factors, milk became extremely scarce during the dry season between 2006 and 2010 and mini-dairies were forced to process powdered milk.

From 2011 onwards, the situation began to improve because of the intervention of several non-governmental organizations, as well as decentralized foreign cooperation that replicated the technical scheme developed by SODEFITEX and the ISRA on a gift basis with little or no coordination. This sustained dairy production and supply to mini-diaries (12 operating in 2013) but was not designed to solve the structural constraints of the dairy basin. Rather, interventions exacerbated problems for several reasons. Firstly, gifts of cottonseed stocks encouraged neither durable solutions to supply problems nor the development of local institutions to obtain feed regularly on credit. Secondly, poor coordination among developers exacerbated both opportunistic strategies (little incentive to repay loans and mutualize funds) and dynamics of competition and patronage between outsiders (non-governmental organizations, decentralized cooperation) and local actors (professional organizations, decentralized public institutions). Local actors depended on outsiders for access to international aid, while the same outside groups needed clients to raise funds from donors. In short, the "logic of gift" met the short-term performance requirements of the projects and maintained dependency relationships but was a major obstacle to promoting real autonomy for local actors. Despite all this, local herders successfully adopted protein supplementary feeds as a means to develop complementarity between agriculture and cattle-herding and so produce milk throughout the year. During our fieldwork, milk production with the Ndama breed was still considered an attractive option in the peri-urban area, despite high cottonseed prices (150 CFA francs/kg in 2013). In fact, an increase in cattle fertility and the improved health of both cows and calves were cited as the principal benefits of supplementing feed for milking cows during the dry season, rather than the income generated by milk sales (Magnani, 2016: 217-224).

The dairy basin of Richard Toll: a classical intensification scheme to improve production in pastoral systems

In 2006, a dairy factory, Laiterie du Berger (Shepherd's Dairy, LdB), was set up in Richard Toll, in the Senegal River valley. The city is home to Senegal's most important agro-industry, namely growing and processing sugar cane. The dairy factory was supplied with milk collected from hundreds of pastoralists living in the close hinterland of the valley (35 km around the city).

Between 2006 and 2008, the dairy factory exclusively processed local milk and targeted a niche market of upper class urban and expatriate consumers. During this period, the dairy faced severe economic difficulties due to the low volumes collected 10 . In 2008, thanks to the innovative character of the initiative, the dairy was able to form an alliance with danone.communities, which provided LdB with expertise in strategic areas such as manufacturing, marketing and distribution of dairy products. The partnership attracted private and public backers that invested in the dairy and in its collection basin 11 . Powdered milk was included in the supply, particularly during the dry season, to ensure that factory production met consumer demand throughout the year.

10 In 2007, the dairy collected on average 1 066 liters/day, compared to the plant's processing capacity of 10 000 liters/day. The creation of a successful brand led to a significant increase in the volume of sales12 . Following this commercial success, new directives were issued regarding the milk collection service.

From 2011, management stressed the need to stabilize milk collection, which was strongly affected by seasonality and pastoral mobility in the arid environment. In order to reduce collection costs, LdB officials tried to convince pastoralists to settle their milking cows during the dry season. They set up a credit scheme to promote the systematic use of industrial feeds and sugar cane residues, with the support of the sugar cane industry (Compagnie Sucrière Sénégalaise -Senegalese Sugar Company), a strategic ally of LdB, which has historically had tense relations with pastoralists because of land expropriation. As shown by our research, the dairy failed to significantly reduce the variability, both seasonal and annual, of pastoral milk production, which was dependent on the highly variable quality and quantity of natural pastures. In fact, the change envisioned by the industrialists was in several ways inconsistent with the practices of the pastoralists, who sought to take advantage of new commercial opportunities during the rainy season, when selling milk to the factory was extremely advantageous. At such times, dairy production was abundant because of fresh pastures and inputs were not required. In contrast, during the dry season, milk sales were less profitable or indeed unprofitable for pastoralists. The speed at which pastures were consumed depended on the quality of the previous rainy season, and once they were exhausted milk sale revenues failed to cover the cost of the input needed to feed dairy cows. Some herders kept some milking cows at their camps for dairy collection, while moving the rest of the herd in search of water and pastures, for a number of different strategic reasons. Firstly, those herders facilitated the mobility of the herd by stabilizing the elderly people and children, while ensuring their access to milk.

Secondly, they secured access to animal feeds on a credit basis, which was particularly important in case of drought. Thirdly, they acted to ensure rainy season milk sales, as the dairy factory prioritized the herders who supplied milk on a continuous basis. In fact, while the industrialists tried to induce a relative specialization in dairy production and to encourage the use of animal feeds, pastoralists promoted the multi-functionality of their systems and tried to limit the use of the expensive inputs (Magnani, 2016: 258-274).

From a broader perspective, a focus on livestock system intensification ignored patterns of change in local natural resource management. Historically, Fulani pastoralists enjoyed seasonal access to the Senegal River valley. They spent the rainy season in the hinterland, watering livestock in ponds and feeding them with fresh grass. At the beginning of the dry season they moved to the river valley, following the flood-recession agriculture techniques practiced by peasants and using pastures available in the depressions flooded by the river [START_REF] Touré | Fulani of the Ferlo[END_REF]. This system, which relied on complementarity between both agriculture and pastoralism, and dry and flooded areas, gave pastoralists access to valuable feeding pastures for cattle during both the dry and rainy seasons. From the 1950s, development interventions brought major changes in agricultural and pastoral systems. The first driver of change was the construction of a dense network of boreholes in the hinterland, which made water available throughout the year and encouraged pastoralists to settle around them. This compromised the rules governing access to grasslands in the hinterland [START_REF] Barral | Le Ferlo des forages. Gestion actuelle et ancienne de l'espace pastoral[END_REF].

The second major driver of change was the development of the Senegal River valley as an exclusive space for irrigated agriculture. Between the 1980s and the 1990s, pastoralists were progressively excluded from the resources of the humid zone [START_REF] Santoir | Décadence et résistance du pastoralisme. Les Peuls de la vallée du fleuve Sénégal. [The Decline and Resistance of Pastoralism. The Fulani of the Senegal River Valley][END_REF] and became more dependent on the highly variable pastures of the dry hinterland in which they were settled. Transhumance in the valley during the dry season was replaced by scattered movements following the progressive depletion of pastures around the boreholes. As a consequence, pastoralists started to use expensive animal feeds to compensate for the decline in the quality of pastures and their highly variable availability from year to year. These changes in access to resources and pastoral practices are crucial to understanding why producing milk during the dry season is now difficult and costly for pastoralists. But the main contradiction underlying LdB's social business is that its major partner in the dairy intensification scheme, CSS Sugar Company, has been, and still remains, a central actor in development interventions and natural resource management patterns in the area.

Since the mid-1970s, CSS has grown sugar cane on around 10 000 ha of irrigated land between Richard Toll and Lake Guiers. Since 2010, in order to increase sugar production, the company has appropriated several thousand more hectares of pastoral land, this time directly in the hinterland of Richard Toll.

In any case, with the support of its partners, LdB grew quickly and within a few years became Senegal's second largest dairy company, with commercialized volumes reaching 2 200 t in 2013. Though the social business image of the company was built on the collection of milk among pastoralists, the record sales and strong increase in production were mostly due to imported powdered milk. The latter accounted for at least half of LdB's production between 2012 and 2014 13 .

Discussion: looking beyond technical dimensions

The analysis of these case studies shows the urgent need to overcome a technical approach in public policy on dairy development. In fact, our research shows that political, economic and social dimensions play an overwhelming role in all the situations under analysis.

Around Dakar, an industrial dairy production model was directly transferred from Western countries without any integration envisaged with local livestock systems, breeds, skills or resources. It was hoped that the model would spread as more businesses sought to imitate it and became willing to invest. But dairy farms were disconnected from the industrial processing sector and their product was in direct competition with imported tax-free powdered milk. Moreover, the artificialization of production systems failed: animals were suffering because of badly adapted installations and feed rations; their milk production was variable and costly. In the absence of a solid professional culture and a coherent, incentivized, long-term policy framework, the hope that an intensive dairy production model would become widespread remained unrealistic. All in all, public research was undertaken for fifteen years, mainly in experimental stations, and supportive public initiatives were implemented only for seven years. In fact, technicizing the challenges of dairy development in this context ignores the centrality of social organization, production and marketing constraints, as well as the absence of incentives for local dairy production and processing. Indeed, a professional organization representing dairy farmers has unsuccessfully called on the government for measures including the preservation of agricultural land around Dakar, tax incentives for investments in local milk processing and production, the inclusion of local dairy products in school canteens and support for setting up farms.

The Kolda case study illustrates how policy frameworks can be a double-edged sword that leads to the emergence of a dairy basin as well as to its progressive disruption. A holistic public support framework was successfully implemented in the dairy basin of Kolda for around two decades, thanks to the partnership between 13 Source: LdB, 2014.

two public institutions with a development mandate. Its temporary success depended on the provision of essential services: access to feeds under preferential terms, coordination among stakeholders, and technical assistance. This ended with the privatization of the cotton company and the dismantling of public development services as a result of the liberalization of the agricultural sector, creating an institutionalized dependency on international aid. The attempt to replace public interventions with a service center financed by a foreign cooperation agency failed because of the conflicting and opportunistic behavior of the institutions involved. In fact, cooperation among partners was impossible in the absence of a policy framework supervising and organizing private aid interventions. The scaling down of public support to non-governmental organizations from the middle of the 2000s saw the dairy sector destructured. Competition among development actors, a short-termist approach to projects and performance requirements, clientelistic relations and the co-optation of local organizations discouraged collective action and organization in the dairy basin. As a consequence, it is now regarded by national authorities and development organizations as a problematic example of dependency and a lack of local expertise. Nevertheless, the dairy basin still exists and seems to be an appropriate response to the needs of a landlocked city like Kolda as well as to herders' constraints.

The third case study, examining the LdB dairy basin, is often referred to as a success story in the regional academic and institutional literature on poverty-focused rural development [START_REF] Wane | Food security and nutrition as basic indicators of socioeconomic sustainability in a context of innovation[END_REF]. Its high-risk approach to the challenges of fresh milk supply in drylands gained support and interest from several donors and partners in the name of social business. This type of operation is part of a new two-way development model. On one hand, partners' statements are consistent with the notions of inclusive growth and markets, promising increased profit through a business meeting the needs of the poor [START_REF] Arnani | Mirage at the Bottom of the Pyramid. How the private sector can help alleviate poverty[END_REF][START_REF] Binet | Le rôle des entreprises et des fondations privées dans la gouvernance mondiale agricole et alimentaire. [The Role of Private Businesses and Foundations in the Global Governance of Agriculture and Food[END_REF][START_REF] Gradl | Understanding the markets of the poor: A market system approach to inclusive business models[END_REF]. On the other, LdB dairy consortium is archetypical of a modern intervention in development, whereby public funds are used to directly support private investments [START_REF] Gabas | Nouveaux regards sur la coopération pour le développement et ses transformations[END_REF]. Though presented as part of the social business movement, the technical intensification pattern promoted by LdB ignores fundamental changes in local economy and society generated by a set of development interventions. Pastoralists have shown that they have valid economic and ecological reasons to resist a further intensification of their systems. Through its alliance with a major actor of the local agribusiness, the dairy project, while appearing to be an innovative and socially oriented initiative, legitimizes contemporary and historical trends of land grabbing in grassland areas.

Thus, it would be unwise to base dairy policy on the expected generalization of this specific case, even though this model of local milk collection offers several opportunities for pastoralists. Whatever the future of the LdB dairy project, it challenges the political framework in which a private-foundation-aid system is responsible for providing support for local livestock development and the supply of dairy products to the urban market. If such fragmented and poorly coordinated interventions were to become standard in Senegal, as in other sub-Saharan countries heavily dependent on aid, it would increase uncertainty about the state's capacity to regulate food policy and to deliver basic goods and services to their population.

Conclusion

The article demonstrates that focusing and acting mainly on technical issues of dairy development has two main implications. Firstly, it overlooks the political choices and economic conditions that hinder the development of local dairy production in West Africa, namely the competition of powdered milk which remains tax-free, and the lack of a framework of public policies to support the production and processing of milk. Secondly, it ignores the relationships between the herders, their environment, markets, livestock and social dynamics.

The case studies offer different examples of how local livestock production systems are either plainly ignored or required to change with limited regard for their own constraints and strategies. At present, Senegal is still lacking a comprehensive and coherent dairy policy. Within the current policy framework, the artificialization of livestock systems, a central goal of the dominant technical paradigm, has little or no chance of working.

Intensive dairy systems, developed without regard to their environment, need easy access not only to feeding inputs, but also to the equipment and technical knowledge necessary to run a specialized dairy system. This would require price controls and protective tariffs, negotiated in a regional economic space where West African states should be able to stimulate global production by promoting regional complementarities. Given the high level of risk involved in working with local milk, the investment it demands and the large availability of powdered milk, achieving a balance more favorable to local dairy development will require the political commitment of national governments and regional institutions to implement coherent dairy, livestock and commercial policies. This policy framework should include measures for the improvement of local milk production (incentives, assistance, adapted territorial development schemes), collection and processing (infrastructure facilities, fiscal incentives) as well as progressive regulations discouraging the simple repackaging of powdered milk, improving transparency around powder qualities, introducing local sourcing requirements for dairy processors and increasing tariffs for powdered milk imports. Most serious actors in the Senegalese and regional dairy sector, including the main regional professional organisation networks and a number of NGOs and research organisations, actively campaign for a more comprehensive policy framework such as this, but still receive little attention from public authorities. Some initiatives look promising in this regard, such as the 'regional offensive for the promotion of local milk in West Africa' currently being drafted within the Economic Community of West African States (ECOWAS), or the announcement by the Senegalese government that it will consider tax exemptions for the processing of local milk. Nevertheless, the outcome of such processes remains unclear: ECOWAS is having difficulty in finding funds and the proposed tax exemptions have not yet been scheduled. Furthermore, the Economic Partnership Agreements being negotiated between the European Union and ECOWAS could be a major obstacle to the implementation of any sectoral regulation in the future. This regional free trade agreement provides for the complete liberalisation of the import of powdered milk (in 25 kg bags) within five years of its implementation and requires EU approval of any future revision of custom tariffs.

In any case, a more realistic dairy policy should be based on a better understanding of, and improved support for, local livestock systems in all their diversity. A policy building on local knowledge, practices and social organization to encourage productive interactions between livestock systems and environment could help to develop and support alternative production systems. This could be a more effective answer to the challenges of rural and livestock development and urban consumption, as well as a coherent way to promote food sovereignty in Senegal and West Africa.

  11 Partners were: Danone and danone.communities, CSS Senegalese Sugar Company, Crédit Agricole Grameen Bank, public donor agencies (Coopération de Monaco -Monaco Cooperation, Agence Française de Développement -French Aid Agency -(AFD)) and a French non-governmental organization (GRET). Research institutions monitor its dynamics: International Livestock Research Institute (ILRI), French Agricultural Research for Development -(CIRAD), International Food Policy Research Institute (IFPRI).

Mouve, funded by the French National Research Agency (ANR).

The EU milk quotas were introduced in 1984 to avoid overproduction and price volatility. They were abolished in 2015 with the purpose of increasing European production and exports.

In 2014, 40 kg of industrial feed for dairy cows cost 7

CFA francs.

In 2013, only one industrial dairy was buying 6 000 liters of milk per week, from a big farm at 400 CFA francs/liter.

1 140 t in 2011, compared with 430 t in 2007.

Acknowledgements

This article has stemmed from a paper presented at the « 2015 World Food Policy Conference, The Future Faces of Food and Farming » (17 th -18 th of December 2015, Bangkok, Thailand). We express our gratitude to

the French National Research Agency (ANR) and French Agricultural Research and International Cooperation Organization (CIRAD) for their financial support.

Conflict of interest statement

On behalf of all authors, the corresponding author states that there is no conflict of interest.