Gido Hakvoort
email: gido.hakvoort@gmail.com

Hayrettin Gürkök
email: h.gurkok@utwente.nl

Danny Plass-Oude

Michel Bos

Mannes Obbink
email: mobbink@gmail.com

Poel
email: m.poel@utwente.nl

Measuring immersion and affect in a brain-computer interface game

Keywords: Brain-computer interfaces, affective computing, immersion, games

have widely been used in medical applications, to facilitate making selections. However, whether they are suitable for recreational applications is unclear as they have rarely been evaluated for user experience. As the scope of the BCI applications is expanding from medical to recreational use, the expectations of BCIs are also changing. Although the performance of BCIs is still important, finding suitable BCI modalities and investigating their influence on user experience demand more and more attention. In this study a BCI selection method and a comparable non-BCI selection method were integrated into a computer game to evaluate user experience in terms of immersion and affect. An experiment with seventeen participants showed that the BCI selection method was more immersive and positively affective than the non-BCI selection method. Participants also seemed to be more indulgent towards the BCI selection method.

Introduction

A brain-computer interface (BCI) can be described as a communication link between the brain and the machine. In a BCI system, signals from the brain are analyzed to determine the user's state of mind or intentions, which in turn can be translated into actions [START_REF] Van Gerven | The brain-computer interface cycle[END_REF]. BCI systems have been applied for medical use to help disabled users by giving back mobility [START_REF] Galán | An asynchronous and non-invasive brain-actuated wheelchair[END_REF] and breaking the isolation of people with physiological disorders [START_REF] Farwell | Talking off the top of your head: toward a mental prosthesis utilizing event-related brain potentials[END_REF][START_REF] Hoffmann | An efficient P300-based braincomputer interface for disabled subjects[END_REF].

As successful applications of BCIs become news and commercial BCI input devices become publicly available, BCIs are finding their way into recreational use. However, as the scope of BCI applications is expanding from medical to recreational use, the expectations for BCIs are also changing. Currently they are unable to meet the high performance and accuracy of existing input modalities such as mouse and keyboard, and are therefore unfit as replacement. Instead they should be seen as separate modalities which can be used beside, or in combination with, existing input modalities [START_REF] Nijholt | Brain-Computer Interfaces for HCI and Games[END_REF]. However, using BCI as input modality still comes with many challenges. Where increasing the performance of BCIs has always been an important goal for medical studies, the way they are applied as modalities and the influence they have on the user experience is becoming more and more important for recreational BCI applications.

Whether BCIs are suitable for recreational applications is as yet unclear as they have rarely been evaluated for user experience. They may turn out to be valuable additions for recreational applications such as games which are developed to be challenging and enjoyable. Moreover the inaccuracy of BCIs can become a challenging factor in games. As gamers love working with new technologies, are capable of adapting quickly to a new environment and are used to the concept that games have to be mastered [START_REF] Nijholt | Turning shortcomings into challenges: Brain-computer interfaces for games[END_REF], they may be more indulgent towards BCI modalities.

The purpose of this study was to evaluate a BCI system for user experience in the terms of affect and immersion. As making selections is an important aspect in many games and BCIs are frequently used to make selections, a BCI selection method was used in this study. One of the most frequently used brain signals in BCI systems to make selections is the steady-state visually evoked potential (SSVEP) [START_REF] Beverina | User adaptive BCIs: SSVEP and P300 based interfaces[END_REF]. In most cases SSVEPs are triggered by presenting a modulated visual stimulus with a periodic signal, usually at frequencies above 5 Hz, to a user. The periodic signal of the stimulus can then be traced back in the measured brain signals which are mostly recorded from the occipital region of the scalp [START_REF] Shan | Assessment of Steady-State Visual Evoked Potential for Brain Computer Communication[END_REF]. The power of an SSVEP only covers a narrow bandwidth matching that of the stimulus [START_REF] Lopez | Statistical characterization of steady-state visual evoked potentials and their use in brain-computer interfaces[END_REF]. This makes them relatively easy to detect, which is why the BCI selection method used in this study was based on SSVEP. The BCI selection method and a comparable non-BCI selection method were integrated into a computer game where both introduced a challenge factor. As the BCI selection method would be able to directly translate the user intentions into in-game actions, it was expected that it would enrich the user experience in terms of immersion and affect.

How immersion and affect can be influenced by input modalities will be explained in the background in section 2. The BCI and non-BCI selection methods and how they were integrated in a game will be described in section 3. In section 4 the experimental setup and how both selection methods were evaluated will be explained. After this, the results of the experiment will be reported, followed by the discussion and the conclusion.

Background

Immersion

Immersion has meaning in various contexts, such as while reading a book, watching a movie or playing games. Whether the term is used consistently in these contexts is unclear. However, for playing games there seems to be a shared concept of immersion among gamers [START_REF] Brown | A grounded investigation of game immersion[END_REF]. Immersion in games is often accompanied by high levels of concentration, losing track of time and empathy.

In a study by Brown et al. [START_REF] Brown | A grounded investigation of game immersion[END_REF] an attempt was made to define immersion within games. In their study they examined the concept of immersion experienced by gamers. Their results indicate that immersion is not just a static experience, but has different levels of involvement. They defined three levels of involvement: engagement, engrossment and total immersion. They also state that to reach a certain level of immersion, a number of barriers must be crossed. Some of these barriers are related to human characteristics, such as personal preferences, empathy and the will to invest time and attention. Others are related to the construction of the game such as the graphics, a plot and atmosphere. However, to reach a state of total immersion an important barrier to take is related to the controls. Through them gamers translate their intentions into in-game actions [START_REF] Pagulayan | User-centered design in games[END_REF] and virtually controls should become invisible to the gamer. As intentions originate from the brain, users first need to translate their intentions into real world actions to handle the controls. Even if these real world actions become virtually invisible for the user, they still need to be performed. Using a BCI to detect intentions may allow them to be translated directly into in-game actions, making the real world actions redundant.

In a study by Jennett et al. [START_REF] Jennett | Measuring and defining the experience of immersion in games[END_REF] immersion in games was further investigated. They identified five factors of immersion: cognitive involvement, real world dissociation, emotional involvement, challenge and control. As in the study of Brown et al., some factors were related to human characteristics (cognitive involvement, real world dissociation and emotional involvement) and others were related to the construction of the game (challenge and control). To measure these factors, as well as the total immersion, they developed a questionnaire which was also used in this study to measure the immersion while using the BCI and non-BCI selection methods.

Affect

Affect can be referred to as experiencing emotions and has some overlap with immersion [START_REF] Jennett | Measuring and defining the experience of immersion in games[END_REF]. It has a large impact on how well users are able to perform tasks and how they respond to possible usability problems. According to Norman [START_REF] Norman | Emotion & design: attractive things work better[END_REF], a more positive affect causes users to be more indulgent towards minor usability problems. Although there are many dimensions associated with affect, according to Picard [START_REF] Picard | Affective computing[END_REF] the three most commonly used dimensions of emotion are valence, arousal and dominance. Picard also notes that the valence and arousal dimensions are critical in recreational applications.

Bradley et al. [START_REF] Bradley | Measuring emotion: The self-assessment manikin and the semantic differential[END_REF] developed a questionnaire, the the self-assessment manikin (SAM), to measure emotional responses in these three dimensions. In Fig. 1 some emotions associated with valence and arousal can be seen. Integrating the selection methods into an enjoyable, challenging and task oriented environment, such as a game, should result in a more positive affect in terms of valence and arousal which will aid users to overcome the inaccuracy of the selection methods.

Selection Methods

To measure the effects of the BCI and non-BCI selection methods on the user experience in terms of immersion and affect, the selection methods were integrated into a simple game. The game, called Mind the Sheep!, offered the players an enjoyable, challenging and task oriented environment.

Mind the Sheep!

Mind the Sheep! consists of a playground representing a meadow on which a few obstacles, such as fences, gates or trees are placed. There are three dogs in the playground which are controlled by the player. Depending on the objectives of a specific level, the playground can be populated with a number of sheep or collectibles. A screenshot of the game can be seen in Fig. 2 with ten white sheep and three black dogs. The goal of the game is to gather all sheep into a pen or gather all collectibles as quickly as possible using the three dogs. Players can use one of the selection methods to select one of the three dog.

To move a dog, players point at any location on the playground with the mouse and start the current selection method by pressing the left mouse button. As long as they hold down the mouse button the selection method continues to be operative thereby increasing the accuracy of the selection method. Releasing the mouse button stops the selection method and one of the dogs is moved to the location indicated by the player. When players indicate a position unreachable for the dogs, the instruction is ignored. As the accuracy of the selection methods increase over time, there is a trade-off between accuracy and speed. It also requires users to multi-task as they need to concentrate on a dog and keep an eye on the sheep at the same time. The dogs use a simple A* search based path finding algorithm to move to a specific location on the map. By default, sheep will walk around and graze randomly. However, when a dog approaches, they will tend to flock and move away from the dog allowing them to be herded in a desired direction. The flocking behavior is introduced by using the boids algorithm [START_REF] Reynolds | Flocks, herds and schools: A distributed behavioral model[END_REF]. By positioning the dogs at strategic locations on the map a flock of sheep can be directed into the pen.

BCI Selection

To use SSVEPs for making selections, stimuli emitting unique periodic signals should be presented to a user simultaneously. When a user focuses on one of the stimuli, the periodic signal of that stimulus can be traced back in the user's brain signals. As each stimulus represents a single target, the corresponding target can then be determined as the selected one. As users would not want to continuously make selections, they were able to start and stop this selection method thereby controlling the presence of the stimuli. The size of the stimuli and the frequency of their periodic signals have an influence on the how well they are reflected in user's brain signals. Therefore, these properties were determined in a pre-experiment study.

In the pre-experiment study a small white cross was placed at the center of an LCD monitor on a black background (Fig. 3). During the study participants were exposed to different types of trials, in which the presented stimulus varied in size and frequency. The detailed setup of the pre-experiment study was described in [START_REF] Hakvoort | Comparison of PSDA and CCA detection methods in a SSVEP-based BCI-system[END_REF]. Based on the work of Volosyak et al. [START_REF] Volosyak | Impact of Frequency Selection on LCD Screens for SSVEP Based Brain-Computer Interfaces[END_REF], 7 different frequencies (6 Hz, 6.67 Hz, 7.50 Hz, 8.57 Hz, 10.00 Hz, 12.00 Hz and 15.00 Hz) were used. Their study showed that frequencies which are integer factors of the refresh rate of an LCD monitor are more suitable for presenting stimuli. Using the factor of the refresh rate produces a more stable stimulus frequency because only whole frames are visible on the LCD screen. The diameters of the stimuli were set to 2 and 3 centimeters, which is consistent with the work in the literature [START_REF] Cheng | Design and implementation of a brain-computer interface with high transfer rates[END_REF][START_REF] Lin | Frequency Recognition Based on Canonical Correlation Analysis for SSVEP-Based BCIs[END_REF].

In each trial a simple stimulus, a blinking white circle, appeared at the location of the cross. The participant focussed for 4 seconds on the stimulus. Between trials, participants had 6 seconds rest to relax their vision. All trials were presented 25 times and were placed in a random order prior to the study, thus for each participant, 25 segments of 4 seconds of data were recorded for each different trial.

The results of the pre-experiment study with 7 participants indicated that a good set of frequencies is 10 Hz, 12 Hz and 15 Hz with a diameter of 3 centimeters. Without any training, the frequencies in this set were classified correctly with an average recall of 78.1 % (σ = 18.5) using a CCA-based detection method which will be further explained in section 4.2.

Non-BCI Selection

The BCI selection method introduces a challenge factor when a selection is being made as users need to concentrate on a stimulus to make an accurate selection. The main challenge is to gather enough data to be able to make a good detection, which is directly related to the time the selection method is operative. Although it would be much easier for users to make a selection by pointing and clicking with a mouse, this would offer little challenge and give the non-BCI selection method a great advantage when compared with the BCI selection method. To pose a similar challenge in the non-BCI selection method, it was modelled to be similar to the BCI selection method in terms of the time required for an accurate selection.

Similar to the BCI selection method users were able to start and stop the non-BCI selection method. When operative, the dogs were highlighted one at a time with an increasing highlight period. The diameter of the stimuli were kept the same as in the BCI selection method, 3 centimeters. When users stopped the selection method, the current highlighted dog was selected.

To make an accurate selection, users had to react in time when the dog they wanted to select was highlighted. With a highlight period of 250 ms users should have enough time to react as this is close to the average human reaction time [START_REF] Lansing | Reaction time and EEG activation under alerted and nonalerted conditions[END_REF]. The highlight period should reach 250 ms only by the time that is equal to the time needed to make a selection using the BCI selection method, which is around 2.5 seconds [START_REF] Lin | Frequency Recognition Based on Canonical Correlation Analysis for SSVEP-Based BCIs[END_REF]. Therefore, the highlight period started with 100 ms and was increased 5% after every highlight, with a maximum highlight period of 500 ms.

Methods

Experimental Setup

The experiment held in this study consisted of two different sessions. In each session a participant used one of the selection methods (BCI or non-BCI) while playing Mind the Sheep!. Each participant used both selection methods. However, a counterbalanced measures design was used to avoid confounding variables such as learning a strategy to play the game.

Each session was divided into three trials, a familiarity trial, an easy trial and a difficult trial. In the familiarity trial participants could get used to the selection method by selecting and moving the dogs. During this trial, participants had to collect 10 objects which were placed across the playground. Next, in the easy trial, participants had to pen a small flock of 5 sheep using the dogs. During this trial two pens were placed on the playground, one on the left and one on the right of the screen to make the task easier for the participants. Finally, in the difficult trial, participants had to gather 10 sheep, which were more scattered across the playground, into one pen that was placed in the center of the playground. Between the two sessions, participants were given a break of ten minutes.

The layout of the playgrounds across the trials were kept the same to ensure no playground was more difficult for one of the selection methods. However to ensure that participants did not create an optimal strategy for a specific trial, the positions of the dogs, collectible objects and sheep were altered for the different selection methods.

A timeout was set for each trial for the participants to finish the level by collecting all objects or gathering all sheep into a pen. Participants had 3 minutes, 5 minutes and 10 minutes for the familiarity, easy and difficult trials respectively. Since immersion in games is often accompanied by losing track of time, the time left was not visible for the participants. Otherwise it could have influenced their perception of the elapsed time.

The game ran on a PC which was connected to a projector 1 . The projector was mounted on the ceiling and projected the game on a screen approximately 3 meters away from a participant. The sizes of the stimuli were scaled proportionally with the increased distance to the screen. To make sure the frequencies for the SSVEP based BCI selection method were correctly presented by the projector they were checked with a light sensor.

Participants sat on a chair behind a table and by using the mouse on the table they were able to start and stop the selection methods. The data acquisition ran on a separate PC and sent the raw electroencephalography (EEG) data to the game PC.

SSVEP Detection

Prior to the experiment, 32 electrodes were placed according to the international 10-20 system [START_REF] Reilly | EEG Recording and Operation of the Apparatus[END_REF]. For the EEG data acquisition a BioSemi ActiveTwo system2 was used. During each SSVEP selection EEG data was used from eight parietal-occipital electrodes (i.e. Pz, P3, P4, PO3, PO4, Oz, O1, O2). The EEG data was re-referenced to the common average reference (CAR) [START_REF] Cooper | EEG technology[END_REF] of all 32 electrodes, after which a detection method was used to determine which frequency the participant was focusing on.

There are various methods to detect the presence of SSVEP. One of the most popular and widely used detection methods is power spectral density analysis (PSDA) where a fast Fourier transform (FFT) is used to estimate the power spectral density (PSD) of a time window of the EEG signal. The magnitude of each stimulation frequency can then be used for classification. A relatively new approach is using canonical correlation analysis (CCA) where sets of reference signals are constructed for each one of the stimulation frequencies. Each set contains the sine and cosine for the first, second and third harmonic of the stimulation frequency. The re-referenced EEG data and each set with reference signals are used as input for the CCA. CCA tries to find pairs of linear transformations for the two sets such that when the transformations are applied the resulting sets have a maximal correlation. The stimulation frequency with the highest maximum correlation is classified as the frequency the participant was focusing on.

As CCA-based detection methods have some improvements and advantages compared to PSDA-based detection methods, such as better signal-to-noise ratio (SNR), lower inter-subject variability and the possibility of using harmonic frequencies [START_REF] Bin | ShangkaiGao: An online multi-channel SSVEP-based brain-computer interface using a canonical correlation analysis method[END_REF], a CCA-based detection method was used in this study.

Questionnaires and Data Acquisition

To measure the affective reaction of the participants while playing the game, they were requested to fill in a SAM [START_REF] Bradley | Measuring emotion: The self-assessment manikin and the semantic differential[END_REF] after each trial. It was expected that if participants became more frustrated by using a selection method, this would result in higher arousal and lower valence scores. The dominance would also be higher if participants had the feeling that a selection method was working properly and that they were in control.

After each session participants filled in a questionnaire on immersion. The questionnaire by Jennett et al. [START_REF] Jennett | Measuring and defining the experience of immersion in games[END_REF] was used for this. It contains 31 questions and is designed to measure the total immersion as well as five different factors of immersion (cognitive involvement, emotional involvement, real world dissociation, challenge and control). Although valence, arousal and dominance would probably differ between selection methods for which participants have an aversion, this does not necessarily mean participants would not become immersed in the game.

Furthermore some game statistics, such as the number of times a dog was selected, the total number of selections, the average selection duration and the time participants needed to finish a trial were collected while participants played the game. Ideally participants would use all the dogs as this would make it easier to gather the sheep. The number of times a particular dog was selected would be a good indication of how well the selection methods performed for the participants.

At the end of the experiment participants were asked which selection method they would like to use if they were given the opportunity to play the game again. This should have given a good indication of which selection method the participant preferred.

After the experiments, scores were obtained for the total immersion, the five immersion factors, the SAM questionnaire and the game statistics. The results from the SAM questionnaire were averaged over the three trials to get an average score for the valence, arousal and dominance scales. As each participant used both selection methods, the scores were compared using a Wilcoxon signed-rank test to determine if there was a significant difference between the two selection methods.

Participants

Seventeen participants (7 female and 10 male), aged between 17 and 37 (μ = 22.00, σ =4.74) participated in the experiment. All participants except for one had normal or corrected-to-normal vision and described themselves as daily computer users. Although eight participants had at least one-time experience with EEG, fourteen participants had no experience with BCIs. Before the experiment, all participants signed an informed consent form and they were paid according to institution's regulations.

Results

When the 17 participants were asked which selection method they would choose if they were given the opportunity to play the game again, 5 of them chose the non-BCI selection method and 12 of them chose the BCI selection method. This is a first indication that participants prefer the BCI selection method over the non-BCI selection method. A detailed insight might be provided by the scores for immersion, the SAM questionnaire and the game statistics, which are described below.

Immersion

Based on the immersion questionnaire the total immersion score was calculated for both selection methods. On average the participants rated the BCI selection method (μ = 160, σ = 14.55) higher than the non-BCI selection method (μ = 144, σ = 21.89). This difference was significant (Z = -2.155, p = 0.031).

The five immersion factors were also analyzed and the scores, averaged over participants, are shown in Table 1. The scores for all factors, except for the challenge factor, are higher for the BCI selection method. The five immersion factors were examined for significant differences between the BCI and non-BCI selection methods. There are significant differences for the cognitive involvement factor (Z = -2.219, p = 0.026), the real world dissociation factor (Z = -1.992, p = 0.046), the emotional involvement factor (Z = -2.013, p = 0.044) and the control factor (Z = -2.310, p = 0.021). For the challenge factor no significant difference (Z = -0.476, p = 0.634) was found.

Affect

Based on the SAM questionnaire the total SAM scores were calculated for both selection methods and the average results are shown in Table 2. For the valence scale the difference was significant (Z = -2.012, p = 0.044), however, no significant difference was found for the arousal (Z = -0.315, p = 0.752) or dominance (Z = -0.403, p = 0.687) scores.

Game Statistics

The game statistics which were collected during the experiments are shown in Tables 3 and4. They show the number of selections and the average selection time. For the number of selections (Table 3) there are significant differences for the easy task trial (Z -2.202, p = 0.028) and the difficult task trial (Z = -2.107, p = 0.035). However, no significant difference was found for the familiarity trial (Z = -1.866, p = 0.062). Although no significant differences were found for the average selection time (Table 4) between the BCI and non-BCI selection methods for any of the three trials, it can be seen that for the familiarity and easy task trials the average selection times for the BCI selection were around 0.5 seconds higher. However, for the difficult task trial the average selection time was lower.

Discussion

Most participants indicated that they preferred playing the game with the BCI selection method. This seems to be supported by the results of the immersion questionnaire. The total immersion score was significantly higher for the BCI selection method, indicating that participants were more immersed than when using the non-BCI selection method. For the BCI selection method participants only had to make their intentions clear to the BCI system by concentrating on the dog they wished to selected. Besides starting and stopping the selection method, there were no other actions required. However, for the non-BCI selection method, participants still had to translate their intentions into an action, stopping the selection method at the correct time. As participants were able to translate their intentions directly into in-game actions while using the BCI selection method, they might have become more easily immersed.

Further inspection of the five immersion factors showed that all factors, except for the challenge factor, were significantly higher for the BCI selection method. The questions related to the challenge factor were about the game itself. As the averages of the challenge factor were almost equal for the two selection methods, they indicate that participants did not find the game more challenging using one of the two selection methods. For using the selection methods, the control factor might be a better indicator. As the control factor was significantly lower for the non-BCI selection method, it indicates that participants had more trouble using the non-BCI selection.

The results of the SAM questionnaire indicate that participants were more content using the BCI selection method. The results of the cognitive involvement and real world dissociation factors were also significantly higher for the BCI selection method. This could have been caused by the fact that participants had to concentrate on a dog while using the BCI selection method and did not have to translate their intentions into real world actions.

Some participants developed a strategy to deal with the trade-off between accuracy and speed. When they wanted to be accurate in their selections, they waited long enough to make an accurate selection. However, when they wanted to be quick, they moved all three dogs as one by pressing rapidly at a location on the playground. Although this behavior was observed for both selection methods, for the BCI selection method participants appeared to switch between precise and quick whenever they wished. However, for the non-BCI selection method they appeared to prefer only making quick selections, explaining the significantly higher number of selection for the non-BCI selection method.

For the BCI selection method the number of selections was lower and, although not significant, the average selection time was higher. Participants were also more immersed and content. Apparently, participants accepted that for a good SSVEP detection they had to wait a couple of seconds. However, for the non-BCI selection method they understood that it was related to their own reaction speed and suddenly they appeared to be in a hurry. Although the non-BCI selection method was modeled to be similar to the BCI selection method, it might have had an effect on the preference of the participants, as they did not want to wait to make a selection. The non-BCI selection method did introduce the same challenge and required participants to multi-task similarly to the BCI selection method. However, participants seemed to be more indulgent towards the BCI selection method than towards the non-BCI selection method. This could be caused by the curiosity of participants for the BCI selection method or the self overestimation by participants while using the non-BCI selection method.

Conclusion

In this study a BCI system was compared to a non-BCI system to evaluate the user experience in terms of immersion and affect. For the BCI system a selection method based on SSVEP was integrated into a game, introducing a challenge factor. A comparable non-BCI selection method based on time was also implemented into the game, introducing an equal challenge. Seventeen participants played the game with both selection methods in three trials. They rated each selection method on immersion and affect.

The results show that the BCI selection method was found to be more immersive and positively affective than the non-BCI selection method. While using the BCI selection method participants were able to directly translate their intentions into ingame actions, which made it easier for them to become more immersed. In this case, the user experience in terms of immersion and affect seemed to be improved while using the BCI selection method. Furthermore, participants appeared to have more patience when using the BCI selection method than when using the non-BCI selection method, which could have been caused by the curiosity of participants for the BCI selection method or the self overestimation by participants while using the non-BCI selection method.

For future studies it would be interesting to look at long term effects on immersion and affect. Is the BCI selection method still significantly more immersive and affective when participants are used to it? Another question is whether the indulgence towards the BCI selection method is permanent or only temporary. It would also be interesting to add a selection method based on pointing and clicking which was left out of this research. Thereby testing for the cognitive load as the selection methods used in this study required participants to multi-task. Given the intended purpose of this research, it would also be interesting to use commercial BCI input devices (e.g. Emotiv's EPOC). This would also require a proper study comparing the equipment used in this research and commercial BCIs to determine the differences and if they are feasible to use within the setup of this experiment. Other (non-)BCI selection methods, such as speech and gestures could also prove to increase immersion and affect.

Fig. 1 .

 1 Fig. 1. Emotions in the valance and arousal space

Fig. 2 .

 2 Fig. 2. Screenshot of Mind the Sheep! with three black dogs and ten white sheep. The pen is located in the center.

Fig. 3 .

 3 Fig. 3. Screen layout of the monitor during the pre-experiment study.

Table 1 .

 1 Scores of the five immersion factors, averaged over participants. Values are represented as μ(σ) with * indicating a significant difference with p < 0.05.

		non-BCI	BCI
	Cognitive *	53.12 (9.01)	58.47 (5.36)
	Dissociation *	25.18 (5.64)	28.06 (4.79)
	Emotional *	54.35 (8.54)	59.88 (5.95)
	Challenge	20.88 (2.89)	20.71 (2.34)
	Control *	32.06 (5.77)	37.06 (5.08)

Table 2 .

 2 Average SAM scores, the values are represented as μ(σ) with * indicating a significant difference of p < 0.05.

		non-BCI	BCI
	Valence *	6.37 (1.55)	7.08 (1.31)
	Arousal	4.82 (2.31)	4.53 (2.37)
	Dominance	5.65 (2.46)	6.08 (1.64)

Table 3 .

 3 Average number of selections for each trial, presented as μ(σ) with * indicating a significant difference of p < 0.05.

		non-BCI	BCI
	Familiarity	12.53 (4.87) 10.47 (2.67)
	Easy *	43.00 (26.27) 27.88 (7.86)
	Difficult *	98.88 (65.90) 74.12 (30.28)

Table 4 .

 4 Average selection time (in seconds) for each trial, presented as μ(σ).

		non-BCI	BCI
	Familiarity	1.92 (0.86)	2.49 (1.71)
	Easy	1.96 (1.04)	2.64 (2.63)
	Difficult	1.95 (1.31)	1.71 (0.85)

Mitsubishi WD510U, 93.3", 60Hz, 1360x768

BioSemi, Amsterdam, The Netherlands

Acknowledgments. The authors gratefully acknowledge the support of the BrainGain Smart Mix Programme of the Netherlands Ministry of Economic Affairs and the Netherlands Ministry of Education, Culture and Science. The authors would also like to thank Michiel Hakvoort for his technical support on the game and Lynn Packwood for improving the language of this paper.


Moushumi Sharmin
email: sharmin2@illinois.edu

Brian P Bailey
email: bpbailey@illinois.edu

Making Sense of Communication Associated with Artifacts during Early Design Activity

Keywords: Design, Artifacts, Communication, Ideation, User Study. 11]

Communication associated with artifacts serves a critical role in the creation, refinement, and selection of conceptual ideas. Despite the close relationship between ideas and surrounding communication, effective integration of these two types of design materials are not well-supported by exiting design tools -resulting in ad-hoc and ineffective strategies for managing communication during the design process. In this paper, we report the results of a contextual inquiry (N=15) aimed at understanding communication practices, its role in the design process, and strategies utilized by designers to manage and utilize communication outcomes in relation to artifacts. Our findings show that more than 50% of early design activity consists of three categories of communication (information seeking, brainstorming, and feedback) and communication practice varies as a function of expertise, organizational and social factors. Additionally, novice and freelance designers exhibit greater reliance on online forums to find suitable communication partners to generate and refine ideas whereas experts communicate with other experts or team members for information collection and sharing.

Introduction

Communication is a central part of the ideation process, especially for creative, nonroutine design activity [START_REF] Eckert | Sources of inspiration: a language of design[END_REF][START_REF] Sonnenwald | Communication roles that support collaboration during the design process[END_REF]. Many types of communication (e.g., client correspondence, brainstorm discussions, and feedback on initial ideas) influence the ideation process. Research shows that discussion associated with artifacts promotes design thinking [START_REF] Eckert | Sources of inspiration: a language of design[END_REF], enables generation and refinement of alternatives [START_REF] Sutton | Brainstorming Groups in Context: Effectiveness in a Product Design Firm[END_REF], and contextualizes the design process [START_REF] Bonnardel | Creativity in Design Activities: The Role of Analogies in a Constrained Cognitive Environment[END_REF]. In this paper, we use the term ideation process to refer to activities associated with the generation and evaluation of design artifacts during the early design phases. In addition, we use the term design communication to refer to any type of exchange, verbal (face-to-face, over phone) or written (e-mail, IM, etc.), synchronous (phone) or asynchronous (e-mail) related to ideation activities.

Research on design has underscored the importance of communication in the design process [START_REF] Tang | A Framework for understanding the workspace activity of design teams[END_REF], examining it in specific situations such as studying communication roles [START_REF] Regenbrecht | Carpeno: interfacing remote collaborative virtual environments with table-top interaction[END_REF] and negotiation strategies [START_REF] Sonnenwald | Communication roles that support collaboration during the design process[END_REF][START_REF] Regenbrecht | Carpeno: interfacing remote collaborative virtual environments with table-top interaction[END_REF] within co-located teams [START_REF] Stewart | Single display groupware: A model for co-present collaboration[END_REF][START_REF] Tang | A Framework for understanding the workspace activity of design teams[END_REF] or specific types of communication such as rationale related to design choices [10, 2 Related Work

Studies of Design Communication

The role of communication is well researched in the realm of collaborative and distributed work [START_REF] Chiu | An organizational view of design communication in design collaboration[END_REF][START_REF] Kraut | Informal communication in organizations: Form, function, and technology[END_REF][START_REF] Nardi | The Place of Face-to-Face Communication in Distributed Work[END_REF]. Kraut et al. studied informal communication as a means for improving collaboration and coordination in an organizational setting [START_REF] Kraut | Informal communication in organizations: Form, function, and technology[END_REF], while Chiu examined the effect of team organization on communication [START_REF] Chiu | An organizational view of design communication in design collaboration[END_REF]. Sonnenwald examined communication as a collaboration tool for multi-disciplinary teams [START_REF] Sonnenwald | Communication roles that support collaboration during the design process[END_REF]. This thread of research focused on communication as a means for improving collaboration efficiency. During the ideation process, the role of communication transcends collaboration efficiency, as it allows designers to learn about the design space and guides the generation, selection, and refinement of artifacts. Communication during ideation often includes artifacts such as sketches, drawings, prototypes, and other visuals [START_REF] Eckert | Sources of inspiration: a language of design[END_REF]. Studies focusing on communication therefore offer only a partial picture of the ideation process, ignoring the influence of communication outcomes in the generation and refinement of artifacts. One consequence is that existing tools do not provide adequate support for integration of communication and related artifacts; making it difficult to utilize them during ideation. We aim to fill this gap.

Design researchers have attended to formal and organized communication (e.g., brainstorming sessions) [START_REF] Eckert | Dimensions of Communication in Design[END_REF][START_REF] Stempfle | Thinking in design teams -an analysis of team communication[END_REF]. Eckert and Stacey conducted several studies investigating communication in collaborative design tasks and offered six broad dimensions of communication, including form of communication, task, subject and tool expertise, and objectives for communication [START_REF] Eckert | Dimensions of Communication in Design[END_REF]. Stempfle and Badke-Schaub focused on design thinking as a team process and viewed communication as a representation of individual and team thinking [START_REF] Stempfle | Thinking in design teams -an analysis of team communication[END_REF]. Our research extends prior work by probing the various underlying reasons that motivate and influence communication associated with artifacts in practice.

Studies of Early Stages of Creative Design Practice

Research on early phases of creative design has focused on different types of artifacts and how these artifacts (e.g., sketches and prototypes) impact ideation process [START_REF] Herring | Getting inspired!: understanding how and why examples are used in creative design practice[END_REF][START_REF] Kolodner | Improving Human Decision Making Through Case-based Decision Aiding[END_REF]. Bonnardel studied the influence of information availability on the idea generation process [START_REF] Bonnardel | Creativity in Design Activities: The Role of Analogies in a Constrained Cognitive Environment[END_REF]. Researchers also studied the impact of capturing, accessing, and reusing artifacts in the ideation process [START_REF] Sharmin | Understanding knowledge management practices for early design activity and its implications for reuse[END_REF]. A separate thread of research centered on the creation and utilization of sketches and early prototypes to externalize ideas [START_REF] Landay | Interactive Sketching for the Early Stages of User Interface Design[END_REF][START_REF] Klemmer | The designers' outpost: a tangible interface for collaborative web site[END_REF]. Researchers also focused on facilitating ideation process by capturing the history of the progression of artifacts [START_REF] Klemmer | Where Do Web Sites Come From? Capturing and Interacting With Design History[END_REF]. Additionally, researchers have focused on the influence of workspace activities within design teams during the artifact generation process [START_REF] Tang | A Framework for understanding the workspace activity of design teams[END_REF].

Prior research on early stages of creative design has emphasized the construction of artifacts, especially through sketching, without regard for the rich communication that influenced and was prompted by those artifacts. Researchers consider communication to be an inseparable part of the ideation process [START_REF] Tang | A Framework for understanding the workspace activity of design teams[END_REF] as it not only guides the design process, but also allows designers to represent and support their design decisions [START_REF] Eckert | Sources of inspiration: a language of design[END_REF]. Studying artifacts provides only a partial understanding of the early design process, as it fails to portray thought processes, discussions that prompted changes in artifacts, and decisions that led to the evolution of the ideas. We aim to offer better understanding of the relationship between artifacts and related communication by studying designers' communication practices.

Systems Supporting Design Communication

Most communication support systems focus on capturing decisions and deliberations related to design problems and are aimed to support redesign and maintenance issues [START_REF] Conklin | A Process-Oriented Approach to Design Rationale[END_REF][START_REF] Conklin | gIBIS: A Hypertext Tool for Team Design Deliberation[END_REF][START_REF] Reeves | Supporting Communication between Designers with Artifact-Centered Evolving Information Spaces[END_REF]. Another related class of system supports communication among stakeholders largely by capturing decisions surrounding artifact design [START_REF] Arias | Enhancing communication, facilitating shared understanding, and creating better artifacts by integrating physical and computational media for design[END_REF][START_REF] Atwood | Facilitating Communication in Software Development[END_REF]. Mood boards and similar systems often capture design scenarios, explored alternatives, and early design activity to convey ideas and design choices to clients [START_REF] Garner | Problem Interpretation and Resolution via Visual Stimuli: The Use of 'Mood Boards' in Design Education[END_REF][START_REF] Lucero | Funky Wall: Presenting Mood Boards Using Gesture, Speech and Visuals[END_REF]. These systems try to provide awareness of ongoing design activity by capturing and representing artifacts or specific types of communication (e.g. rationale), but ignore the relationship between artifacts and other types of communication (e.g., discussions, feedback, and client preferences) that shapes the ideation process. The resulting systems thus fail to represent the design process, making it difficult for designers to utilize and understand the process in which the artifacts were created [START_REF] Sharmin | Understanding knowledge management practices for early design activity and its implications for reuse[END_REF]. We believe research aimed at understanding designers' communication practice in relation to artifacts can provide valued insight and guide the design of tools that would provide more effective management of the design process.

Methodology

The goal of our study was to understand communication practices during ideation activities holistically, investigate designers' motivations and strategies for initiating, managing, and utilizing communication outcomes, and examine organizational and social factors that influence their communication behavior. Our study consisted of semi-structured interviews with professional designers with varying levels of expertise and coming from different creative design domains. We used self-report data to classify designers as expert and novice. For example, one designer has a total of three years of professional experience and rated his expertise level as "novice." Another designer has more than 10 years of professional design experience and rated herself as an "expert." We also considered two types of work setting, designers who work in an organizational setting (design firms, N=8) and designers who work independently (freelance, N=7). See table 1 for background of the study participants.

The interview had 19 questions guided by our prior research on reuse of existing design knowledge during the early stages of creative design domains [START_REF] Sharmin | Understanding knowledge management practices for early design activity and its implications for reuse[END_REF]. Table 2 lists sample questions asked during the interview. We began the interview by asking the designer to briefly describe a recent or ongoing project and encouraged her to share stories about communication practices during their ideation process to ground the discussion. For example, one designer was working on the design of a social networking site for a corporate setting. During the interview, the designer focused on how communication with clients helped to accumulate various types of information needed for designing the site and how discussion with other designers helped to refine his early ideas. Interviews lasted no more than two hours and interviewees received $20 for their participation. Ten of these interviews were conducted in the designers' workspace and the remaining via phone due to distance. While phone interviews limited our ability to directly examine the workspace, we requested the interviewees to share additional materials such as photos of the workspace, screen-captures of the artifact and communication management systems, and records of captured communication with us to gain better understanding of their communication practice.

All of the interviews were audio-recorded and later transcribed. Each of the transcripts were coded separately and later analyzed for recurring themes across interviews. We also collected relevant artifacts such as stored e-mails, IMs, and files containing traces of communication utilized during the ideation process and analyzed these to verify opinions expressed during the interviews and designers' actual practices. Though the study was qualitative in nature, numbers were reported to highlight the relative significance of an observed behavior.

Study Results

We report the results from our study of communication surrounding artifacts during ideation activities. We discuss why, with whom and when communication occurs, discuss communication categories, channels utilized, and strategies adopted by the designers for managing communication during ideation.

Role of Communication in Ideation Process

Communication Accounts for more than 50% of Ideation Activity: Designers deem communication as a core design activity and reported that on an average more than 50% of early design activity involves communication related to artifacts. Designers communicate to learn about existing artifacts, generate ideas, compare alternatives, and refine and select ideas for further consideration. They engage in communication Table 2. Sample of the questions asked during an interview.

Types of Communication

What are the different types of communication that occur throughout the design process?

Frequency and Motivation

How often do you communicate with other designers during the early design phase? What motivates you to do so? Capture and Access Why and how do you capture and access communications for an ongoing or a prior project, if at all? What motivates you to do so?

Medium of Communication

Which is your preferred method for communication during early design (face-to-face, email, etc.)? Why do you prefer this method over the other methods? about the artifacts and utilize the outcomes of communication to guide the design process. Designers leverage artifacts and associated communication to capture the underlying design process and believe that artifacts or communication alone fails to adequately represent their process. As a result, designers want to capture artifacts and related communication together as it facilitates reuse, in line with findings reported in [START_REF] Sharmin | Understanding knowledge management practices for early design activity and its implications for reuse[END_REF]. Existing technology do not support capturing and management of artifacts and communication in one space, resulting in disassociation between these two design components. This forces designers to come up with ad-hoc strategies to link artifacts and communication for effective utilization.

Though designers mentioned engaging in communication throughout the design process; they believed the impact of communication is most significant during the early phases when they are striving to come up with conceptual ideas. We observed designers' workspaces showcasing different types of early design materials, where communication is captured and highlighted in terms of feedback on post-its, annotation on sketches, list of requirements, etc. Figure 1 presents one such workspace where artifacts and related communication are displayed in the idea space to guide the design process. Idea spaces showcasing artifacts and associated communication is typical in all the designers' physical workspaces, indicating a need for better integration of these two design components in the design support tools.

Communication Helps

Resolve "Designer's Block": Fourteen out of fifteen designers interviewed mentioned engaging in communication as a method of getting past "designer's block." Designers consider communication not only necessary but also as a fail-safe method for removing the block. To quote two designers: "There's a point when you reach your road block in the design process and you need fresh perspective, you need someone to ask "hey, what do you think?" That happens a lot." [P4] "Everyone gets stuck no matter how creative or how good you are. And that's when other designers will come out and they might be mean about it, but I like to think that everyone won't be blunt about it. I'll post (in Web forums) to get help." [P10]

Communication in Different Phases of Early Design Activity Information Seeking -Personal Communication is Preferable to Web Search:

The first step during ideation is to collect information for problem formulation. Designers communicate with other designers, clients, and end users to better situate the design problem, to collect information on the product and similar projects, and to collect requirements from clients. Designers also collect information from office repository, the Web, books and magazines. While Web and other sources allow quick access to information, opportunity to learn from other designers' experience makes personal communication the most preferred method for collecting information. Designers search technical information on the Web, but communicate with other designers for collecting subjective information (e.g., feedback, rationale). See figure 2 for most utilized sources of information during ideation activities. Designers also communicate with other designers whom they believe to be invaluable sources of design knowledge, which can't be attained from any other sources. This preference is exemplified by the following two quotes: "There is so much knowledge on gaming culture and you can't find it in Google or you can read so many books, but still not find the answer. You have 100~200 people who have these small pockets of knowledge and together it's pretty formidable." [P7]

Generation and Selection of Ideas -Integration of Artifacts and Related

Communication is Imperative: During ideation, designers mentioned engaging in frequent communication with others designers, especially when they get stuck and need fresh perspectives. After initial research, designers engage in brainstorming sessions to share information, to narrow down the problem space, and to generate, refine, and select ideas for refinement. Research on early design also highlighted the importance of team meetings and brainstorming on the innovation process [START_REF] Sutton | Brainstorming Groups in Context: Effectiveness in a Product Design Firm[END_REF]. Figure 3 depicts one such session where members of a group are engaged in ideation. While these sessions indicate close relationship between artifacts and communication, existing tools support capturing either artifacts or communication. As a result, relationships between artifacts and communications are lost. However, we observed designers making an effort to preserve these relationships by capturing the outcomes of communications using notes and e-mails to themselves and storing these along with related artifacts. When asked, designers mentioned that artifacts and communications separately fail to capture the process and rationale for generating and selecting ideas, and the value lies in capturing these two components together. Eleven out of the fifteen designers mentioned creating notes and/or taking pictures of the white boards filled with discussion points to preserve outcomes of the communication with the other design materials. This indicates a need for tools that would better connect communication outcomes with the other design materials.

Refinement and Evaluation through Feedback: Another type of communication prevalent in early design is feedback, which allows designers to refine, improve and validate their ideas. A significant part of early design communication is targeted to receive and provide feedback. Designers also utilize feedback to learn about potential weakness and strength of their ideas and to examine and enhance the quality of ideas. The most cited reason for feedback request is to receive a fresh and alternative perspective on an idea. One designer summarized this behavior nicely: All of the designers participating in our study mentioned requesting feedback on their ideas, two of the fifteen mentioned refining the ideas before requesting any feedback, and four mentioned requesting feedback throughout the ideation process.

Medium of Communication -A Shift towards Digital Channels

Communication occurs throughout the ideation process; it begins even before designers start generating ideas. Designers utilize different communication channels (face-to-face conversations, over phone, via e-mail and IM) based on the underlying design activity and the phase of the design. Figure 4 presents a distribution of utilized and preferred communication channel -indicating a shift towards the digital channels. While face-to-face communication is considered imperative, digital channels, especially e-mail is the most utilized channel to initiate, manage, and create a record of communication outcomes. Interestingly, 60% of the designers mentioned following up with e-mails after face-to-face or phone conversations. The capability of including images of artifacts along with the discussion and ease of sharing and access make email their preferred choice for communication. One designer stated: "When somebody comes and you show them your final product, and they just think that you put those things together somehow magically but actually there were lot of iteration, there's lot of thinking that went behind it, and it's kind of a way to show -"here's actually what I was thinking.

" [P4]

Designers also try to capture communication outcomes to select the best idea from a number of possible candidates. To some designers selecting the best direction is often as challenging as coming up with numerous ideas [START_REF] Sharmin | Understanding knowledge management practices for early design activity and its implications for reuse[END_REF]. Designers tend to capture early ideas and associated feedback on post-its and use these to analyze alternate directions. Figure 5 shows idea space for a designer where she accumulated her ideas along with feedback received and rationale behind her design choices. She utilized this space not only for selecting a direction but also for showing the client and others her process. Spaces such as this are common in the design workspaces, illustrating the need for better integration of artifacts and relevant communication.

Communication Management: Existing technology poses challenges in the way designers try to manage communication surrounding artifacts. Designers want to record these communications not only for using in the ongoing project, but also as a reference for future projects. Especially, communication with clients in terms of requirements, feedback, and their preferences are stored for potential future projects. Figure 6 presents one such text file that one designer (P9) created to record all the feedback received for an ongoing project. This file is used to keep track of the suggestions from other designers and his reaction to these suggestions. However, the designer expressed frustration as these communications are disconnected from each other and from the artifacts and he has to invest a great deal of effort to create a single space to combine the outcomes of communication and resulting artifacts. Artifacts are typically stored in directory-based file management systems while communication is stored as e-mail archives, chat logs, voice mails, etc. The separation of these two types of design materials forces designers to adopt ad-hoc strategies to connect them together. For example, we observed designers investing lots of effort to record all the communication related to an artifact by creating files that combine summaries of communications received from all different channels. Another popular strategy was to mimic the directory structure in e-mail clients to reduce the burden of management (see figure 7). Similar finding has been reported in [START_REF] Atwood | Facilitating Communication in Software Development[END_REF] for organizing materials in the area of software design.

Influence of Work Setting: Access, Culture, Ownership and Criticism

Work setting influences designers' strategies and motivations for communication. Culture of organization, ownership of ideas, fear of criticism, and access to design resources greatly impact designers' experience surrounding communication. Access to Communication Partners: Designers working in design firms tend to communicate more during the ideation process as they have access to team members and other designers working in the organization. Freelance designers only have access to clients as most of them work alone. Lack of access to other designers and intellectual property issues force them to limit their communication within a selected and trusted group of designers and with clients. Freelance designers often mentioned relying on close friends and family members to bounce ideas off of due to a lack of access to other experienced designers. One freelance designer mentioned consulting his spouse (a non-designer) when faced with challenge during the ideation process. Freelance designers try to utilize online design forums to gain access to other designers who may eventually become trusted communication partners. Every freelance designer mentioned this lack of connection with other designers as one of the key challenges faced during early design phases.

Figure 8 reflects designers' preference for feedback request. For designers working in organizations, team members are the most preferred source (63%), while freelancers mentioned clients (57%) as their primary source for feedback. This difference is due to the accessibility to other designers, clearly indicated by the fact that designers working in organizations never mentioned clients as a potential source for feedback on early artifacts. However, a fairly large number of designers (43% and 50% respectively) prefer to communicate with friends or peers (who are not involved in the project) about artifacts. A significant percentage of freelance designers (29%, mostly novice) preferred online forums, while none of the designers working in firms considered online forums as useful source for feedback.

Organizational Culture: Organizational culture has been regarded as the primary factor that hinders or promotes communication. Team boundary often discourages communication within an organizational setting as designers feel "less comfortable" communicating and providing feedback to other designers who belong to other design teams. One designer shared his experience with different organizational culture and how it impacted his communication behavior: "Many places are hyper competitive and success mattered on how often you won, and mostly jobs will be competitive among a number of people and it was important that you won, and in some places the culture is such that in a way it rewards that behavior. So people stole ideas and it became a territorial thing, in that case you wouldn't share because you couldn't count on the goodwill and good faith...But here the culture is not like that at all as they don't reward behaviors like that. We are all quite comfortable to walk in our buddy's office and share ideas and ask feedback.

" [P14]

Ownership of Ideas and Fear of Criticism: A large number of designers refrain from communicating early ideas within the organization as they fear that negative or blunt criticism may diminish their enthusiasm for the idea. Competition among team members is also mentioned as one of the reasons why designers feel discouraged to communicate. Even designers working as part of a team tend to delay communication until they feel comfortable with the quality of generated artifacts. This behavior is exemplified by the following two quotes:

"Typically you don't communicate as much when you haven't got your idea yet. You don't want to sense that you are stealing from someone else's ideas. You don't want to talk to somebody so that they come up with the idea that you yourself don't feel like it's truly yours. These are the times that I am hesitant to get feedback." [P14]

"I feel that people might criticize things that I am already aware of that need to be changed, so Majority of the freelance designers use online forums for communicating ideas and expressed that lack of control over the audience and the likelihood of receiving negative feedback are their biggest concerns. One designer went as far as boycotting a forum as he considered the feedback posted as negative and discouraging. This behavior is quite common among freelance designers and can be better exemplified by a comment made by P6: "A place like site2 (pseudonym) forum will discourage me to share information, I think there are some fantastic designers there but between site2 and site1,it is a very separate group of people when it comes to personalities. (In site2) They do not hesitate to say that you are an idiot or stupid while in site1 its little bit more laid back, little bit softer, and it's not that harsh." [P6]

Influence of Expertise: Communication Categories, Partners and Motive

Level of expertise influences how and why designers communicate, with whom they communicate, and how do they capture and utilize communication in their design. Communication Categories: While both expert and novice designers mentioned information collection as one of the primary reasons for initiating communication, the types of information that designers request vary depending on designers' level of expertise. Expert designers rarely request technical information from other designers while novices mentioned other designers as the best resource for finding technical information. Expert designers feel socio-psychological pressure of "not knowing enough" and are reluctant to ask for help on technical issues but novice designers consider themselves as learners and feel that they are expected to ask. Expert designers, contrarily, request more for client and product related information to learn more about the design space and from the experience of other designers. Expert designers mentioned that more than 80% of their communication consists of feedback and discussion about design decisions. On the contrary, a significant part of early communication for novice designers is aimed for generating, comparing, and refining ideas along with reputation building. Figure 9

Discussion and Design Implications

In this section we discuss implications derived from lessons from this study. The implications presented are not exhaustive, but they offer guidance for better connecting communication and relevant artifacts and removing barriers for engaging in communication for ideation.

Integrating Communication Traces with Artifacts

Artifacts and surrounding communications are the two main components of ideation process. Communication traces help designers recall their design choices and convey their process and rationale to others. However, the disassociation of artifacts from communication makes it challenging to effectively utilize communication outcomes during the ideation process. Lack of suitable mechanisms for connecting communication and artifacts for long term management makes it extremely difficult to access, retrieve and utilize communication outcomes from ongoing or past projects. Every designer studied expressed frustration as this disconnection forces them to develop ad-hoc strategies and discourages them to revisit existing design knowledge. Linking communication channels, such as, e-mail and IM, with project spaces will allow better integration of artifacts and related communication. When designers communicate through these channels, options should be provided to link the artifacts with the communications. Similarly, designers should be able to access relevant communication from their artifact spaces. Integrating plug-ins in the e-mail clients (e.g., Outlook) to create a bidirectional channel between the communication space and artifact space would allow designers to make this connection. Linking communications with artifacts would require some effort from the designer, but we believe that designers would be willing to invest this effort if it allows better retrievability.

Categorizing and Organizing Communication

Different types of communication influence the design process differently. While some communication allows the designer to select the best direction, others assist to improve the quality of artifacts. Some types of communication have value that extends well beyond the lifetime of a project, while others are only important during an ongoing design. Designers want to categorize and organize communication in a manner that facilitates effective access, retrieval and utilization. However, categorization of various types of communication introduces overhead in the design process, for which designers want to (and can) invest little effort.

Creating a vocabulary for capturing and categorizing different types of communication with related artifacts (e.g., requirement, user preference, design decision, and feedback) would allow effective access and retrieval. Incorporating default spaces (folders for client communication, feedback, rationale) for different categories of communication in the artifact space could reduce the burden of organization on the designer. Alternatively, tags could be utilized to associate different types of design communication with appropriate categories. These tags could be integrated in the e-mail and IM clients and designers could attach one or more tags to link the communication (and relevant artifacts) to the appropriate category. Selecting a specific tag would provide access to all materials linked to that category.

Aggregate Communication from Multiple Channels

Designers engage in communication throughout the ideation process and obtain valuable information from various channels, such as face-to-face and phone conversations, e-mail, IM, online forums, etc. Lack of support for aggregation of communications obtained from various channels makes it difficult and timedemanding for designers to effectively utilize communication in the design process.

While it may not be possible to capture verbal conversations without any effort from the designer, communication that occurs through digital channels can be aggregated automatically. To facilitate lightweight capture of verbal communication, artifact spaces should incorporate free-form text entry spaces such as notes, which will allow designers to add communication outcomes with the artifacts. Allowing aggregation of communication obtained from various digital channels (e-mail, IM, forum) along with relevant design artifacts through lightweight linking could provide a solution to this problem. Add-ons in the e-mail and IM interfaces could be used to link pertinent communication to an artifact. Add-ons could be integrated in the online forums to allow designers to connect selected communications to the artifact space. Ideally, the artifact space should be connected to all communication channels and should provide support for linking communications received from various channels.

Support Finding Communication Partners by Integrating Interaction, Preference, and Availability Information

Designers almost always prefer to communicate with designers who can offer them valuable insight to improve the quality of their design. Expert designers often have access to suitable communication partners (other designers whom they deem fit), but it is difficult for novice and freelance designers to find appropriate communication partners. On the other hand, it can also become demanding for known experts in an area to accept communication (feedback) request from many designers.

A possible solution can be allowing designers to include communication preference and availability in their organization and/or online profile (in intranetworks, wikis). A visual history of projects they have worked on, clients they have worked for, their area of expertise and interest can be attached to their profile and also can be utilized for suggesting communication partner against a designers' query. For an online public setting, past communication can be analyzed including posts they have initiated and responded to. Designers' search for communication partners could be used along with their profile and interaction history to recommend a list of potential communication partners. Designers could select other designers from the suggested list or by analyzing the profiles that best meet their communication needs.

Conclusion

Communication surrounding artifacts is one of the key activities during the ideation process. Though designers utilize communication and design artifacts simultaneously throughout the ideation process, existing research on design focus on these components separately; resulting in tools which make effective utilization of artifacts and related communication challenging. Better technology can assist to integrate artifacts with communication; however, in-depth understanding of communication practices in relation to artifacts is critical before building such systems.

This paper has contributed deeper understanding of communication practices in relation to artifacts during the ideation process. Our findings indicate communication outcomes greatly influence the generation, refinement, and selection of ideas during the early design stages. We also identify organizational and social parameters that influence designers' communication practice. We observed designers making genuine efforts, but struggling to capture communication outcomes with relevant artifacts, indicating a need for better design support tools. We offer guidelines that can be utilized to design new systems or to extend existing tools to better support the interconnection of communication with relevant design artifacts.

Fig. 1 .

 1 Fig. 1. Different types of early design materials: (a) ideas on post-its; (b) feedback on ideas; (c) materials collected from the Web; (d) prototype sketches; (e) product images; (f) physical products; and (g) notes from brainstorming sessions; displayed in a designers' workspace. Artifacts and communication are captured in close physical proximity to assist in ideation.

"

  Usually I'll gravitate towards who I know first. I'll start from my old colleagues, I'll ask my whole group, and then do a search on the Internet. If I am looking for some technical information, I'll first search in the Internet, but if I get really stuck, I'll ask people more about it." [P8]

Fig. 2 .

 2 Fig. 2. Information sources utilized during ideation activities. Sources are listed in order of preference (client is preferred than end-users for information seeking).

Fig. 3 .

 3 Fig. 3. Group communication session targeted to share information and generate ideas.Early ideas are posted on a white board for discussion and selection.

"Fig. 4 .

 4 Fig. 4. Distribution of communication channel use. X-axis represents channels and Y-axis represents number of designers. All but one participant reported utilizing multiple channels.

  communication for a number of reasons. Communication in terms of design decisions, feedback, and thoughts on ideas allows designers to present their rationale to the clients and others. Designers consider capturing and presenting feedback on an idea and rationale for selecting a direction as a way of validating their design. To quote a designer:

Fig. 5 .

 5 Fig. 5. An idea space of one designer. Post-its contain annotated sketches displaying comments, feedback, and rationale for each design choice.

Fig. 6 .

 6 Fig. 6. Combining summaries of feedback received from various communication channels in a single text file.

Fig. 8 .

 8 Fig. 8. Designers' preferred group for requesting feedback. Y-axis represents designers' preference (%). Empty bars indicate there was no preference for the group.

Fig. 7 .

 7 Fig. 7. Managing artifact space and communication space by creating similar structure in the hard drive and e-mail client.

  I want to get to a state where I feel like I have done most of, I have contributed most of what I want to do, and then see what other people think about it as opposed to starting something and ask other people before I am done." [P9]

Fig. 9 .

 9 Fig. 9. (Expert vs. Novice) Designers' motivation for engaging in communication. X-axis represents reasons and Y-axis represents the percent of designers who prefer them.

Table 1 .

 1 Background of study participants.

	Domain	Number of	Work Setting	Level of Expertise
		Participant	Design	Freelance Expert	Novice
			Organization
	Graphic	7 (3 female) 5	2	4	3
	Web	4	1	3	2	2
	Industrial 4 (2 female) 2	2	2	2

  Finding appropriate communication partners often poses a problem for novice designers. Trust plays a significant role in selecting designers for communication about early ideas, often due to fear of negative criticism and threat of exposing unfinished ideas. While expert designers utilize prior experience to find trusted partners, novice designers often struggle in this process. Novice designers go as far as to study the history of communication of designers (collecting information from colleagues or reviewing past communication) to select the best candidates for communication. Novice designers try to build relationships by posting on design forums and by contacting designers personally. However, these approaches help little as designers rarely afford to invest time to analyze communication history of individual designers to find a proper fit. Automated recommender systems can greatly help in the process of finding suitable communication partners. Experience plays a role (in how you utilize it). If you are young, you ask feedback differently and receive it differently, and you would accept even challenging or disappointing feedback. And you also don't have the confidence to say that I hear you, but I don't buy it. The younger you are the more likely you are to do everything anybody tells you. And having more experience, you learn to understand what is important and what might be ok but not certainly important."[P14]

	100 "designer's block." Novice designers also show more openness towards harsh Expert Novice feedback as they view it as learning process. To quote a designer:
		80
	"	60
		40
		20
		0
		shows designers' motivations for
	communication. While both expert and novice designers mentioned communication
	as a means of collecting information, receiving feedback and reciprocity, novice
	designers communicate more to receive creative input on ideas than expert designers.
	Communication Partners: Utilization of Communication Outcomes: Expert and novice designers' tend to
	communicate their ideas at different times within the ideation process. Novice
	designers tend to communicate throughout the ideation process and use the feedback
	to refine ideas. Expert designers rarely share their initial ideas, waiting till it reaches a
	certain point where they are either satisfied with the idea or are suffering from