Toni Robertson
email: toni.robertson@uts.edu.au

Jeannette Durick
email: jeannette.durick@uts.edu.au

Margot Brereton

Kate Vaisutis
email: kathleen.vaisutis@qut.edu.au

Frank Vetere
email: f.vetere@unimelb.edu.au

Bjorn Nansen
email: hansenb@unimelb.edu.au

Steve Howard
email: showard@unimelb.edu.au

Emerging Technologies and the Contextual and Contingent Experiences of Ageing Well

Keywords: Ageing population, ageing well, social technologies, tangible technologies, diversity

Based on a series of interviews of Australians between the ages of 55 and 75 this paper explores the relations between our participants' attitudes towards and use of communication, social and tangible technologies and three relevant themes from our data: staying active, friends and families, and cultural selves. While common across our participants' experiences of ageing, these themes were notable for the diverse ways they were experienced and expressed within individual lives and for the different roles technology was used for within each. A brief discussion of how the diversity of our ageing population implicates the design of emerging technologies ends the paper.

Introduction

We are engaged in a project that investigates sociophysical interaction conceptualised as the entanglement of tangible and social interaction. With commitments to phenomenological and participatory approaches, as well as the recognition that all human action is both embodied and situated, our project is grounded by the exploration of the roles that emerging social and tangible information and communication technologies can play in ageing well. This context provides the actual living bodies, objects and physical environments that such research depends on. It also responds to its pressing significance to many developed societies where governments and other agencies are seeking to evolve policies and strategies to provide appropriate, adequate and costeffective services to their ageing citizens within limited and tightening budgets. Design and use of new and emerging technologies can contribute to the alignment of the desires of ageing people to remain active and in control of their lives with the goals of governments to encourage healthy, active and financially independent senior citizens and so minimise their reliance on expensive government services (eg [START_REF] Andrews | National Strategy for an Ageing Australia[END_REF].

We have begun to explore this space where actual ageing bodies meet with new social and tangible technologies, as well as with still-developing social policies, through an initial series of scoping interviews with ageing people. This paper is not intended as a comprehensive discussion on the findings of those interviews (see [START_REF] Robertson | Knowing Our Users: Scoping Interviews in Design Research with Ageing Participants[END_REF] for a preliminary discussion of findings), nor is it an attempt to systematically challenge the myths and stereotypes that exist about older people. Instead, our interest is to explore the major issue that 'shouted' from our data: the diversity of our participants, which existed despite the limited demographic and the assumed homogeneity of ageing people that we encountered both in prevailing social attitudes and much of the research on ageing and gerontechnology (see Lindley, Harper & Sellen 2008 for a literature review of this topic).

We begin by briefly describing the series of interviews before teasing out the areas of diversity and related richness that were both shared and defining of the lives of our participants. From there we explore the highly contextual and contingent ways some common aspects of ageing were experienced and expressed in the day-to-day lives of our individual participants and the role new and emerging technologies were playing in these experiences. We end the paper with a brief discussion of the implications such diversity has on the design of emerging technologies.

The Interviews

Scoping interviews are designed as a small, open corpus of loosely-structured interviews that are used to evaluate, ground and refine the initial understandings, assumptions and concepts of a research team in projects such as this one where the development of ethnographic understandings of the domain of intended use are an important part of the process [START_REF] Robertson | Knowing Our Users: Scoping Interviews in Design Research with Ageing Participants[END_REF]). Both their design and analysis were driven by the needs of the project as design research [START_REF] Cross | Designerly Ways of Knowing[END_REF]. This means that our concerns are less about exhaustive analysis of what currently exists and more about checking our assumptions, focusing the research team with shared understandings of what ageing well meant to those who were actually doing the ageing and so developing an informed orientation to the aims of the research project. The interviews were intended to provide a ground from which to investigate what might be technologies of value in the future and how we might initiate their design and uptake. They were designed to solicit both demographic and experiential data including fitness and activity levels, community and social engagement, use of and attitudes to various kinds of information and communication technologies and applications, future work and retirement plans, and current practices around keeping in touch with friends and families. Each participant was also asked to describe what ageing well meant to them and to add anything else about ageing that they felt relevant to our project. Twenty interviews from four groups of ageing people have been completed, transcribed and analysed. We interviewed five members of each group. The groups were chosen to represent an aspect of ageing of particular relevance to the overall project: maintaining health and mobility, community engagement, and social and family relationships. We sought people aged between 55 and 75 who were still very active, in-cluding some still in full time employment, some working part time and some who were retired from paid employment but engaged in community activities of various kinds. Participant contexts included patients in a community rehabilitation hospital in Sydney who had joint replacement surgery 10-14 days prior to their interview; members of an ethnic community organisation in the Illawarra district of NSW; members of large national and voluntary community service organisations in Brisbane and a group who, for various reasons, were childless. Men and women participated equally in the interviews and the group included people from cities, regional and rural areas of Eastern Australia.

The interviews were completed and transcribed in batches with initial analysis of the first ten used to generate areas of attention that could be further addressed in the remainder. The analysis of the full series included combining and comparing different participants' contributions to each area of questioning as well as identifying both commonalities and areas of difference that might be more thoroughly explored by field study and iterative prototyping in the remainder of the project. In our analysis we were mindful of Star's recommendations to listen for the special language used by the participants and for anything that appeared 'strange, weird and anomalous' (Star 2010, p. 605). The first recommendation maps closely to the central HCI design principle expressed by variations of 'Know the user population', while the 'strange, weird and anomalous' can help us develop insights into the diversity of our participants, the richness of their experience and relationships, and how these might refine our focus on the roles social and tangible technologies might play in ageing well.

The Diverse Experiences of Ageing and Technology Use

Summarised very broadly, our participants' views of what ageing well meant to them were remarkably similar. Good health, with a particular emphasis on mobility and fitness; social agency in their interactions with family and friends; independenceincluding both physical and financial independence in their daily lives; and some kind of ongoing work and/or community involvement were repeatedly identified as central to the maintenance of current and future well-being. Our participants all expressed their desire to maintain for as long as possible, their capacities to actively experience the areas of their lives that defined their shared sense of ageing well. However, while our participants' views of ageing well were very consistent, their actual ageing bodies were not. Their bodies were the bodies of people who had led long lives. They were old enough for their various individual genetic, cultural and environmental influences to have expressed themselves, along with the inscriptions made on their bodies by their actual life experiences, such as the work they did, how well they had 'looked after themselves', their access to health care, good food and a safe environment, the communities in which they lived and the kinds of social activities, cultural mores and expectations these provided, as well as various random life events and accidents. So what it would mean and require for each participant to maintain good health, mobility and fitness varied enormously in practice. While the desire to remain active was also common, the activities our participants wanted to continue were similarly varied. And while all our participants wanted to maintain their social agency and ongoing relationships with families and friends, their social networks and how they were experienced and managed were very different.

Our participants were already using information and communication technologies and had learned to use them at work or when they had recognised a need or advantage to do so. The use of word processing, email and various web services, such as online banking was common. Given our focus on the roles that social and tangible technologies might play in ageing well, our participants' engagement with and attitudes towards new and emerging technologies were as contextually and contingently defined as other aspects of their ageing selves. In the remainder of this section we explore the relations between our participants' attitudes towards and use of communications, social and tangible technologies and three relevant themes from our data that, while common across our participants, were notable for the diversity of their experience and expression. These themes are: staying active, friends and families, and cultural selves.

Staying active

Maintaining an active lifestyle was cited by all participants as being central to ageing well and framed as being part of a cycle of habits and behaviours, including social activities and physical exercise that all impacted one another. Maintaining good health was considered central to keeping mobile and maintaining the social agency and physical independence that each of our participants valued so highly:

-"your body deteriorates a lot quicker if you don't keep moving" -"poor health stops you living well. It stops your quality of life". All our participants recognised that their bodies had changed with age in ways that had affected their mobility and the activities they enjoyed. Several were dealing with recent cancer scares and most had some kind of age-related health condition such as diabetes, arthritis, high blood pressure and general aches and pains. But the health effects of ageing were very specific to each individual; impacted each of them in distinct and diverse ways and each responded to them differently. One participant told of the shift from soccer playing and a life of physically demanding jobs to games of billiards and extensive volunteer work at his local community club. Another longed to enjoy gentle travel and gardening after a working life involving a great deal of hectic, work-related travel and active sports that had led to early joint degeneration. Another still played tennis regularly (but no longer in competition), watched cricket instead of playing it and walked a great deal, including daily walking a dog that was jointly owned with several other similarly-aged friends, who also regularly walked him.

At least half our participants were still working either full time or in various stages of reducing their work hours and moving into full retirement. Those who were fully retired were active in various kinds of community and volunteer work even holding leadership positions in their various community groups. The activities our participants engaged in varied widely and included (among just twenty people): gardening, sport (eg golf, tennis, pistol shooting and bowls); explicit exercise (eg cycling, dancing, hydrotherapy, aerobics, gym programmes, swimming, walking-alone, with others or with pet/s); playing chess, Scrabble, billiards and single-user computer games; actively contributing to community organisations and community projects; travelling (domestically and internationally)-individually, together or in larger organised groups (eg. cruises, bicycle and walking tours); taking a caravan around Australia; studying, both formally and informally; and engaging in a rich and varied range of social interactions with family and friends. The common element among all participants and their chosen activities was their desire to maintain their capacity to continue them.

Only one of our participants reported using any kind of technology as part of staying physically active -in this case a mobile app was used to record speed, distance, energy consumed etc during daily walks. Most participants had some knowledge, even positive experiences, of console games gained via interactions with their children and/or grandchildren. However, none were interested in acquiring a game console of their own. Most participants explained they were "too busy" for games. Several added they were not interested "I'm not a games person; not even of the board variety" while others indicated that if relevant they might be interested. For example, one had played online Scrabble with his adult child as an informal way to stay connected while another reflected that he would like "someone to play a game of chess with". But tangible technologies involving active bodily movement as input remained largely unfamiliar and unused among our participants at the time of the interviews.

Friends and Families

Our participants all had families and networks of friends that varied in their conventionality, size, geographic spread, frequency of interaction and emotional connectedness. Most participants had children and grandchildren; some had been divorced, others widowed and some had remarried and/or settled with new partners. Others still had never married yet maintained close, large and supportive networks of friends: "I've never been a family person. I've always been more into friends". Participants noted that it wasn't only their bodies that were affected by the changes ageing brings, but also their relationships with other people. Staying active was central to maintaining these relationships. One participant, a retired semi-professional golfer said: "Physical activity is my number one priority […] I know that grandchildren will be on the way. I want to be able to physically be with them. I don't want them looking at grandma sitting in a chair and who can't do anything, because I want to enjoy them." Another commented: "whilst we can still interact with the young ones we will. I like to get on the floor with them but I'm not as able as I was two years ago." Others were concerned about needing to be cared for by friends and families or noted the changing needs of their ageing friends: "old friends who really do decline or change or have to move or that sort of thing. Dealing with that is something that I was not prepared for".

Phones, both landline and mobiles were the usual means of keeping in touch with others. Only one participant did not have his own mobile phone but he used his wife's mobile when necessary. Another used his mobile very infrequently, mainly when travelling, but used email intensely for both work and social contact. For others, mobile phones were enmeshed in their everyday lives. SMS messages were popular es-pecially within close relationships: "I will SMS forever and a day, particularly to the kids". Email use was frequent and well-established. All participants had heard of Skype with around half of them using it to maintain contact with distant family and friends. One was using it very frequently to maintain contact with a close friend in another country who was very ill. Facebook and even LinkedIn were also used to maintain contact with distant relatives and friends. Another was following a blog written by an old school friend who was travelling around the country in a caravan.

Physical distance between our participants and their geographically dispersed friends and family was reflected in varying ways in the regularity of interaction and the types of technology used. Phones, SMS and email were the first choices for close and regular contact-both for organising social activities and/or for just keeping in touch that is, maintaining relationships-but these were complemented by the use of Skype and Facebook for maintaining contact with those further away and with larger social groups such as wide family relationships and old school friends: "for staying in touch with people. Even if it's just to see what they're doing, as opposed to actually communicating with them." We did not find any examples where our participants had used Facebook for forming new friendships or engaging with apps or marketing.

Cultural Selves

Ageing people, by definition, have long embodied histories; they have lived though many relationships and many changes over time, not just with people but with places and objects including a great variety of technologies. Their social identities have been produced and shaped by the lives they have led. All our participants had their own very specific histories that shaped how they defined and lived their social roles, their values and the priorities of their current lives. Among our participants there were still differences in how communication technologies were used, particularly among our older participants who had migrated to Australia as young adults. Aspects of the cultural self that we discuss here pertain to cultural origins, life histories, gender roles and generation.

All participants noted the importance of family and friends. Some of the participants, who had migrated from Europe, had large, extended families with many members still living overseas. The group from the Illawarra-based community club were skewed towards the older end of our demographic and shared a common ethnic and cultural identity. Traditional roles of husband and wife seemed stronger within this group though even here there were still some anomalies. For example, in one household, the husband used a variety of communication technologies regularly to keep in touch with family and organise get-togethers. This included using Facebook and videoing family events, editing these and then copying the final product to DVDs that he posted to relatives abroad. On the other hand his wife, who claimed to be uncomfortable with technology, used her mobile phone extensively for immediate and frequent social contact and organisation with close relatives and friends.

Well, we've both got a mobile phone, and of course I've got the Internet too. I keep in contact with SMS and emails. Most of our kids work. The way to get to them is to send them a message-SMS 25 cents. So even if they are working it doesn't matter. My wife doesn't use SMS. She rings. She's not a real tech . . ." But in another household within the same group, the female participant possessed the technical skills (aided by her granddaughter's guidance) and her husband, whose health was poor, relied on her to organise and maintain frequent contact with their extended family.

Differences in technology use and attitudes to it also reflected the type of work our participants did or had done. For example, one participant, a farmer who also ran a small earth moving business, explained: "<female partner> does most of my computer work for me. I sit there and dictate and she writes it out. It's a typing issue . . . I find it a bit frustrating to sit down at a computer". He had always done his paperwork manually but had learned to use internet banking, to search for information online and to read email. He understood and could manage the computers that were part of his earthmoving equipment and had learned to maintain home's Internet connection despite living in an area with frequent lightning strikes. It was his partner who did most of the emailing and used both Skype and Facebook: "<female partner> uses Facebook, but I would never go on Facebook; I reckon it's a waste of bloody time." Among the younger participants and the city-dwellers there were no obvious gender differences in either familiarity with or use of the different technologies.

Our participants readily acknowledged generational differences in technology usage within their own families and circles of friends-particularly the use of mobile phones and Facebook. While this was at times accompanied by dismissive comments about Facebook from some of the male participants, for most it was a simple acknowledgement of technological change and generational differences. One participant, after commenting on his grandchildren's addiction to Facebook, added "if they haven't got a telephone, it's like cutting one of their arms off or something. They're lost". But later in the interview, commenting on his current use of a mobile phone and his own youth, remarked: "I don't know how people used to get on then without phones and iPods or whatever they call them".

Discussion

The demographic for our interviews was a relatively narrow one: white, middle-class, between the ages of 55 and 75 and living in the eastern states of Australia. All participants shared a strong sense of what ageing well meant to them, that is, one that privileged maintaining health, mobility and independence, and active engagement with their families, friends and local communities. Yet within this group of peoplechosen because they fitted an 'ageing' demographic-some were still working, some were semi-retired and others fully retired; some were very computer literate while others were comfortable only with (mobile) phone use and basic email; all had very different physical and/or personal needs that were being managed in a wide range of ways and their reasons for engaging with technologies, the selection of which technologies to use and what they were actually used for varied widely.

Our participants made choices about the technologies they used based on specific needs, relevance and the availability of supporting infrastructure. They had already appropriated a number of communications technologies into their everyday lives and were in various stages of engaging with newer social technologies. There were different levels of familiarity with some of the newer tangible technologies but little interest, at this stage, in expanding their use of those currently available. Most of all, our interviews provided a snapshot of the ongoing appropriation by our participants of new technologies that were not specifically age-related but part of the general social, technological and physical infrastructure in which ageing people live. And they reminded us that our potential users' familiarity with ICTs is dynamic, diverse and unbounded. Most importantly our findings highlight the diversity of the ageing population and the need for technology compatible with both diverse use and diverse users.

Diversity within our chosen demographic was multi-dimensional and often unpredictable, confirming the need to continue to question common assumptions about both ageing and the use of new and emerging technologies by ageing people. It was clear that our participants lived their lives within the range of norms and expectations available within their culture, even as they insisted on negotiating their own pathways through ageing. In the process they were actively reinterpreting these same cultural norms and expectations. Importantly for our current context, the recognition of the specificity of ageing bodies and the activities that are available to them-including the appropriation of new and emerging technologies-foregrounds the further recognition that ageing people have always been and will always remain embedded within their ever-changing social and cultural worlds. Indeed it is that embeddedness that they are seeking to maintain as they continue to age.

Acknowledgements

This research is funded by the Australia Research Council Discovery Grants Program DP110101999. We are grateful to our participants for their contribution.


Masatomo Kobayashi

Tatsuya Ishihara
email: tisihara@jp.ibm.com

Akihiro Kosugi
email: a1kosugi@jp.ibm.com

Hironobu Takagi
email: takagih@jp.ibm.com

Chieko Asakawa

Question-Answer Cards for an Inclusive Micro-Tasking Framework for the Elderly

Keywords: Micro-Tasks, Gamification, Skill Assessment, Ageing, Elderly, Senior Workforce

has the potential to help "longtail" senior workers utilize their knowledge and experience to contribute to their communities. However, their limited ICT skills and their concerns about new technologies can prevent them from participating in emerging work scenarios. We have devised a question-answer card interface to allow the elderly to participate in micro-tasks with minimal ICT skills and learning efforts. Our survey identified a need for skill-based task recommendations, so we also added a probabilistic skill assessment model based on the results of the micro-tasks. We also discuss some scenarios to exploit the question-answer card framework to create new work opportunities for senior citizens. Our experiments showed that untrained seniors performed the micro-tasks effectively with our interface in both controlled and realistic conditions, and the differences in their skills were reliably assessed.

Introduction

In many developed societies, increases in the elderly population and declines in the working-age population are serious social issues. For example, in Japan, which has the oldest population in the world, 24.6% of the population is over 65 as of March 2013 [ 1]. The retirement of baby-boomers is expected to reduce productivity while increasing the demand for healthcare and economic support. To address these trends, the senior workforce could be more utilized and their participation in work can help them maintain their independent lives. It is known that work benefits people in many ways, for example by reducing the risk of death while improving their well-being [START_REF]Gerontology -Overview and Perspectives, 3rd Ed[END_REF]. However, the age-related loss of physical, sensory, and cognitive abilities and declining health may prevent senior citizens from participating in full-time jobs. Only a few exceptional seniors are highly active, even though many senior citizens have a desire to work and contribute to their society [START_REF]Active Ageing[END_REF]. As a result, a considerable fraction of the "long-tail" elderly workforce and their valuable knowledge and experience remain unutilized. They need more flexible work opportunities, so they can participate in part-time jobs whenever they want to and at their preferred locations [START_REF] Leibold | Managing the Aging Workforce[END_REF]. The key to success is how to exploit their abilities that have not declined with age (e.g., linguistic knowledge [START_REF]Gerontology -Overview and Perspectives, 3rd Ed[END_REF]) while avoiding any risks related to declining abilities.

The information-communication technology (ICT) is a key to such flexible work. Online communication tools allow distant collaborations and outsourcing to remote freelancers. Internet-connected mobile devices remove restrictions on workplaces. Among such ICT capabilities, this study particularly focuses on micro-tasking as used in crowdsourcing. It is one of the most suitable ways to work with a long-tail workforce, allowing occasional participation in small tasks at home without requirements for continuous commitment. The examples of micro-tasking range from simple, labor-intensive tasks to complicated, intellectual tasks as sampled in Section 2. Statistics show that the number of crowdsourcing workers has grown by more than 100% each year, reaching 6.3 million as of 2011 [START_REF] Loten | Small firms, Start-ups Drive Crowdsourcing Growth[END_REF].

However, most senior citizens are currently excluded from micro-tasking. For example, the participants in the Amazon Mechanical Turk (MTurk) are mainly younger workers [START_REF] Ross | Who are the Crowdworkers? Shifting Demographics in Mechanical Turk[END_REF]. A small study we conducted with local senior citizens in conjunction with [START_REF] Hiyama | Question First: Passive Interaction Model for Gathering Experience and Knowledge from the Elderly[END_REF] found that none of them had ever participated in micro-tasking, such as contributing to MTurk, Wikipedia, or Q&A services, even when they had Internet connections. The literature suggests two reasons: limited ICT skills and concerns about new technologies. Although Internet-connected personal computers (PCs) and mobile devices have become increasingly popular even among senior populations, the elderly are often regarded as passive users of ICT, whose uses of technologies tend to be limited and to favor existing functions [START_REF]Use of ICT at Home[END_REF][ 9] [START_REF] Leung | How Older Adults Learn to Use Mobile Devices: Survey and Field Investigations[END_REF].

Our work aims to create an encouraging framework to accelerate elderly participation in micro-tasking. The primary target users involve senior citizens who have ICT devices such as smartphones or PCs but who do not actively use such technologies, who appear to be the majority of the senior population, at least over the next decade. First, we conducted a questionnaire-based survey to identify the elderly's requirements for the framework and to investigate their current usage of ICT. Next, based on the survey results, we introduce two technical foci of the framework: an interface design that minimizes the effort in learning; and a skill assessment mechanism that allows skill-based task recommendation. The interface uses the metaphor of stacked question-answer cards to allow senior workers to participate in micro-tasks with guided, simple, and consistent interactions (Fig. 1). The skill assessment uses a probabilistic model to calculate the skill level based on the results of micro-tasks.

Here is the structure of this paper. In the next section, we discuss related work. We then describe the concept of our inclusive micro-tasking framework, followed by a summary of the questionnaires, descriptions of our interface design and skill assessment mechanism, and some practical scenarios for our framework. Next we describe the prototype implementation. In the first experiment that involved senior and young participants, we tested the usability of our interface and the feasibility of skill assessment with touchscreen tablets. The second experiment examined the framework with home PCs. We conclude by discussing the implications of the experiments.

Related Work

Micro-Tasking. Crowdsourcing, where workers perform small pieces of work called micro-tasks via the Internet, has been used in many ways such as image recognition to help people who are blind [START_REF] Bigham | VizWiz: Nearly Real-Time Answers to Visual Questions[END_REF], character recognition [START_REF] Von Ahn | reCAPTCHA: Humanbased Character Recognition via Web Security Measures[END_REF], translation [START_REF] Callison-Burch | Fast, Cheap, and Creative: Evaluating Translation Quality Using Amazon's Mechanical Turk[END_REF], and even user studies [START_REF] Kittur | Crowdsourcing User Studies with Mechanical Turk[END_REF]. Crowdsourcing is typically regarded as a means to easily access inexpensive labor, but some approaches such as VizWiz [START_REF] Bigham | VizWiz: Nearly Real-Time Answers to Visual Questions[END_REF] have been proposed to exploit social networks for more sophisticated participation. Also, crowdsourcing is useful for enriching the social network information itself. Guy et al. showed crowdsourcing can be used to gather tags for people and social networks [START_REF] Guy | Guess Who? Enriching the Social Graph through a Crowdsourcing Game[END_REF]. They showed that micro-tasks that ask about social networks can help update obsolete information in social applications.

Crowdsourcing was originally used for solving simple tasks but has expanded into more complex tasks. Kulkarni et al. proposed a framework to decompose complex tasks into micro-tasks [START_REF] Kulkarni | Collaboratively Crowdsourcing Workflows with Turkomatic[END_REF]. They showed that even the work of decomposing the complex tasks into simple tasks could be crowd-sourced. Soylent decomposes crowdsourced text-editing into three steps: find, fix, and verify [START_REF] Bernstein | Soylent: A Word Processor with a Crowd Inside[END_REF]. Noronha et al. showed that nutritional analyses can be crowdsourced by decomposing the tasks into several sub-tasks [START_REF] Noronha | PlateMate: Crowdsourcing Nutritional Analysis from Food Photographs[END_REF]. We assume that some of decomposed micro-tasks may require simpler ICT skills while still benefiting from the wisdom of age, and are thus especially suitable for senior workers.

Senior-Friendly Systems. What assists and hinders the use of ICT by the elderly?

The user interface is a critical factor when designing a system for senior citizens. Leonardi et al. found that seniors preferred intuitive touchscreen interfaces over keyboards [START_REF] Leonardi | An Exploratory Study of a Touchbased Gestural Interface for Elderly[END_REF]. Kobayashi et al. reported that mobile touchscreen interactions are "enjoyable" for seniors and their skills with such interfaces improve rapidly [START_REF] Kobayashi | Elderly User Evaluation of Mobile Touchscreen Interactions[END_REF]. Those studies motivated us to include touchscreen devices in the primary targets of It seems acceptable.

(a) (b) (c)
Could you revise this sentence?

Done

It seems to b acceptable.

It seems acceptable.

Fig. 1.

Examples of micro-task cards, which ask (a) for a product's name (to help a person who is blind), (b) to revise a sentence, and (c) to choose the better sentence.

our framework. The user interface needs of senior citizens have also been discussed in Web accessibility research [START_REF]Web Accessibility and Older People: Meeting the Needs of Ageing Web Users[END_REF]. There are no standard accessibility guidelines specific to the elderly. However, it is known that seniors have requirements that in many ways are similar to those of people with disabilities, since their physical, sensory, and cognitive abilities tend to decline as they age.

The Office for National Statistics in the U.K. reported that typical senior citizens use their mobile phones only for phone calls and text messaging and avoid using Web browsers and other applications [START_REF]Use of ICT at Home[END_REF]. Kurniawan concluded that senior citizens tend to be fearful of unfamiliar technologies [START_REF] Kurniawan | Older People and Mobile Phones: A Multi-Method Investigation[END_REF]. She also found that seniors are passive users of mobile phones, which means they mostly receive phone calls and text messages rather than originating them. Leung et al. reported that the preference to use trial-anderror decreases with age and senior citizens prefer to have instructions [START_REF] Leung | How Older Adults Learn to Use Mobile Devices: Survey and Field Investigations[END_REF]. Hiyama et al. used question-answer interactions through phone calls and text messages as an alternative means for the elderly to participate in social media [START_REF] Hiyama | Question First: Passive Interaction Model for Gathering Experience and Knowledge from the Elderly[END_REF]. Those studies led us to exploit passive interaction styles that can be used without trial-and-error.

Handling Worker Skills.

A major problem of crowdsourcing is the difficulty of assuring the quality of the results. Since the tasks are distributed to many people, there are wide variations in workers' skills and risks of vandalism. There are several ways to remove low quality results. CrowdFlower [ 22], one of the major crowdsourcing services, provides a function to filter noisy workers by distributing some tasks whose ground truths are known. By checking the results of these tasks, the workers who do not have skills can be filtered from the results. Another approach to assure the quality is aggregating multiple workers' output while assessing the skill of each worker and the difficulty of each task at the same time [START_REF] Whitehill | Whose Vote should Count More? Optimal Integration of Labels from Labelers of Unknown Expertise[END_REF]. This approach assumes a correct answer exists for each task and the more skilled workers will agree on the correct answer.

Heimerl et al. showed micro-tasks requiring expertise could be efficiently done by distributing tasks to skilled workers [START_REF] Heimerl | CommunitySourcing: Engaging Local Crowds to Perform Expert Work via Physical Kiosks[END_REF]. How to search for the experts is an active area in information retrieval research. For example, Macdonald et al. proposed a method that finds experts by using multiple sources (such as resumes and webpages) to build skill profiles [START_REF] Macdonald | Voting for Candidates: Adapting Data Fusion Techniques for an Expert Search Task[END_REF]. Guy et al. showed that the content in social applications could help find people related to specific keywords [START_REF] Guy | Harvesting with SONAR: The Value of Aggregating Social Network Information[END_REF]. These projects assumed that the candidates actively used social tools in their daily lives, an assumption that is often strained for senior citizens. As already noted, the elderly tend to be passive users of these technologies. Also, they tend to hesitate in sharing their personal information due to privacy concerns [START_REF] Pfeil | Age Differences in Online Social Networking -A Study of User Profiles and the Social Capital Divide among Teenagers and Older Users in MySpace[END_REF]. Thus we decided to devise a new approach to obtain the skill profiles, an approach based on analyzing the results of the microtasks.

Inclusive Micro-Tasking Framework

This section describes our approach for elderly micro-tasking. As noted in Section 2, various types of tasks can be decomposed into micro-tasks and many of them are expected to be suitable for senior workers. For example, among the three steps (find, fix, and verify) in crowdsourced text-editing [START_REF] Bernstein | Soylent: A Word Processor with a Crowd Inside[END_REF], "verify" seems to be the most suitable task for the elderly. It requires less ICT skills (i.e., simply vote to approve work), but benefits from the wisdom of age (i.e., linguistic knowledge). In many workplaces it is known that older and younger workers have complementary knowledge, skills, and abilities [START_REF]Staffing Mature Worker Survey[END_REF], so younger workers can assist older workers with their ICT skills while the older workers may assist the younger workers with their vocational knowledge. If this type of collaboration is supported in micro-tasking, then elderly participation would be encouraged. Since the people with ICT skills can already use standard desktop interfaces, what we need is an easier gateway for senior citizens who are excluded from micro-tasking opportunities.

User Requirements Survey

A survey using a paper questionnaire was conducted to identify the elderly's requirements for micro-tasking framework. We gave the questionnaire to 179 senior citizens in a suburban city and 170 of them responded (for a response rate of 95%). The respondents consisted of 99 males and 71 females, ranging in age from 54 to 84 (mean=67.7, SD=5.3). This survey was conducted as a part of a larger survey regarding ICT and work.

For the usage of ICT, 78% were PC users, with 60% using a PC every day and 88% were mobile phone users, with 61% every-day users. Although most respondents were frequent users of PCs and mobile phones, their usage was limited. The tools they frequently used included word processers, spreadsheets, e-mail, and Web search engines. Meanwhile, they rarely used modern ICT tools such as video chat or a social networking service (SNS). These results indicate they are using specific applications similar to those they used before they retired from work, confirming previous findings that senior citizens tend to avoid active use of new technologies [START_REF] Kurniawan | Older People and Mobile Phones: A Multi-Method Investigation[END_REF]. This suggests that, although the majority of senior citizens now use ICT, we cannot optimistically assume that they will start participating in micro-tasking without additional mechanisms to increase the elderly's easy access to micro-tasking opportunities.

As for requirements for micro-tasking, the majority of the respondents specified: detailed instructions prior to participation (72%) and task recommendations based on their skills and interests (63%). This also confirms previous findings regarding the preference for instructions and the passive usage of ICT [START_REF] Leung | How Older Adults Learn to Use Mobile Devices: Survey and Field Investigations[END_REF]. Based on the results, we defined two technical requirements for an inclusive micro-tasking framework. First, the interface should be simple and versatile. The simplicity makes it easy to learn, while the versatility provides consistent interactions for various types of tasks. Second, the system should have skill profiles for task recommendations. As mentioned in Section 2, although skill profiles can be extracted from resumes, webpages, and social tools, these approaches tend not to work well for senior workers. We need a mechanism to assess workers' skills without explicit skill-related sources.

Finally, regarding their interests in micro-tasks, the respondents were particularly interested in the tasks that require linguistic abilities in their native language and tasks that help people with disabilities.

Question-Answer Cards

To make the interface simple and versatile, we use the metaphor of stacked cards. Each card shows a question that represents a micro-task. Workers perform the task by answering the question. As shown in Fig. 1, the question can be textual or graphical. The answer may be input as free-form text or from multiple choices. Once a task was completed, the card slides out of the screen and the next card appears. This allows the worker to perform multiple tasks in a passive manner without actively searching the task pool for questions to answer. Since a typical micro-task naturally consists of a simple request and response, this fits well with the question-answer interface.

For example, Fig. 1-a shows a micro-task that asks about the name of a product shown in a picture, which simulates a task to help people who are blind [START_REF] Bigham | VizWiz: Nearly Real-Time Answers to Visual Questions[END_REF]. The worker is asked to choose the correct answer by selecting from buttons below the image, where the candidates were generated by a package recognition engine such as used in Yeh et al. [START_REF] Yeh | A Hierarchical Approach to Practical Beverage Package Recognition[END_REF].

The support of multiple choices is important to allow performing micro-tasks without text entry. It is known that senior people have trouble in using the keypad on mobile phones, particularly on a touchscreen [START_REF] Kobayashi | Elderly User Evaluation of Mobile Touchscreen Interactions[END_REF]. The problem is more serious in East Asia, where frequent mode-switching is required to access thousands of characters. For tasks involving a question that is by its nature open, the candidate answers need to be generated in advance, so that senior workers can contribute to final decisions based on their deep knowledge in a particular domain. The candidates may be generated by programs (such as the recognition engine in the example above), or by other (possibly less reliable) workers who use a free-form text interface.

Skill Assessment

To obtain workers' skill profiles without explicit sources, we use a mechanism to estimate the skills from the micro-task results based on a probabilistic model introduced by Whitehill et al. [START_REF] Whitehill | Whose Vote should Count More? Optimal Integration of Labels from Labelers of Unknown Expertise[END_REF]. This mechanism measures a worker's skill by aggregating the results of multiple-choice tasks. The probabilistic approach is needed because, in realistic micro-tasks, the correct answer is often unknown and it is impractical to provide all of the workers with the same sets of tasks to compare their skills. We extended the model in [START_REF] Whitehill | Whose Vote should Count More? Optimal Integration of Labels from Labelers of Unknown Expertise[END_REF], which considers only the completed tasks, to use both completed and uncompleted tasks. This extension is needed because we aim to assess the skills for each worker, whereas the original work aimed to assess the ground truth for each task. Once the skill level is estimated for each task type, the system can recommend appropriate tasks for each worker. The probability of worker i giving a correct answer for task j is represented as: where α c i is the skill of worker i in task type c, β c j is the difficulty of task j in c, L c ij is the answer by i for j in c,σ is a logistic function, and z c j represents the true label that cannot be known directly. The probability is always set to 0 when i has not yet completed j. The values of α c i and β c j are estimated by an Expectation-Maximization (EM) approach. A larger α c i means the worker has a higher skill while a larger β c j means the task is easier. If a worker has a higher probability of giving correct answers in a task type, then that worker is believed to have a higher skill for that type.

p(L c ij = k | z c j = k, α c i , β c j ) = σ(α c i •β c j ),

Elderly Micro-Tasking Scenarios

In addition to micro-tasks such as those sampled in Section 2, there are other types of promising scenarios where our framework could be used for elderly micro-tasking.

Since the knowledge of the elderly will be most effective in various types of advisory tasks, we believe that the question-answer metaphor is particularly suitable for the senior workforce.

• Decision Making: Based on their extensive experience, senior citizens could give advice on difficult topics such as careers and business options. Our card-style interface can be used both for collecting candidate answers and for voting to choose the best answers. • Authoring Support: Senior citizens could contribute to the creation of educational material by using their expert knowledge and linguistic skills. The types of contributions may include translation, proofreading, and other supportive roles as well as writing new material.

• Crowd Accessibility: People with disabilities could benefit from working with remote senior workers in many ways. In addition to real-time assistance such as VizWiz [START_REF] Bigham | VizWiz: Nearly Real-Time Answers to Visual Questions[END_REF], examples include captions and audio descriptions for videos, and making accessible books and websites.

• Product Evaluation: It is difficult for product designers to meet the usability and accessibility requirements of senior consumers. For example, text information such as menus and instructions must be easy to understand. Cards can show prototype interfaces for products and senior citizens can evaluate them.

• Marketing Research: Because of the rapid growth of the senior market, consumer products and service companies are reaching out to the senior population. In the process of developing products and services, enterprises need to research market acceptance and the card-style interface can be a mechanism for such surveys.

In many of these scenarios, the collaboration between the people who create candidate answers and those who make final decisions is a focus. Our framework provides interfaces for those who have weaker ICT skills or who use mobile devices, thus allowing senior citizens to participate in appropriate roles, whenever they want to and at their preferred locations.

Prototype Implementation

We implemented a prototype based on this framework as a Web application with support for various types of devices. The user interface written in JavaScript works on the client side while the skill assessment engine written in Java runs on the server side. The Web-based model allows using a standard server-side program for multiple types of micro-tasks, while sharing much of the client-side code for multiple devices.

We currently have two variations of the implementation: one for mobile touchscreens and one for desktop browsers. Fig. 2-a shows a card on a mobile touchscreen device. The card is asking for the name of the object in the picture, which represents a micro-task similar to [START_REF] Bigham | VizWiz: Nearly Real-Time Answers to Visual Questions[END_REF]. The card can be completed by tapping an answer from several options. Once an answer is selected, the next card will appear on the screen with an animation. The worker can also skip cards or go back to previous cards by dragging across the card to the left or right, respectively. Fig. 2-b shows a card in a desktop Web browser. The card is embedded in an SNS interface as a widget, asking to revise a sentence which represents a micro-task similar to the "fix" task in crowdsourced text-editing [START_REF] Bernstein | Soylent: A Word Processor with a Crowd Inside[END_REF]. The card can be completed by editing the text and clicking on the submit button. The basic design is to the same for the mobile and desktop, except that the desktop interface has "skip" and "back" buttons on top of the card.

The two targets, mobile touchscreens and desktop widgets, were chosen to increase the exposure of senior citizens to micro-tasks. The mobile touchscreen device is known to be easy to use and preferred by the elderly [START_REF] Kobayashi | Elderly User Evaluation of Mobile Touchscreen Interactions[END_REF]. Although smartphone users are still a minority in the elderly population at this time, it is expected to be an increasingly common device in the next decade. This kind of devices is usually kept switched on and carried on all the day, so it will effectively increase their exposure. The desktop widget can be embedded in any existing interfaces that support HTMLbased widgets. The exposure will increase by putting the widget in an interface the users frequently access, such as SNS websites. Although SNS websites are still unfamiliar to most senior citizens, they are becoming popular with them.

Fig. 2-c shows a view that visualizes the estimated skill levels, which we developed to motivate the workers. The skill values for each task type are normalized from 0 to 100 and presented in a radar chart. The average values of all of the workers are also displayed in the chart.

Experiment 1: Controlled Study

Our first experiment sought to test the usability of the card-style interface on a touchscreen device and the feasibility of skill assessment, tested in a laboratory setting with simple micro-tasks.

Settings

Participants. A total of 15 seniors in their 60s to 80s (mean=70.1, SD=6.8) participated in the experiment. We also involved 16 younger people in their 20s to 40s (mean=33.5, SD=3.6) as a baseline. A total of 8 of 15 seniors and 14 of 16 younger people had experience with mobile touchscreen devices before the experiment. The senior participants were recruited locally while the younger participants were employees in a global technology company. All of the participants were native Japanese speakers, and the experiment was conducted in Japanese.

Apparatus. The participants used an iPad. As senior citizens rarely have their own tablet devices at this time, the devices were issued by the experimenters and the experiment was conducted in a laboratory. We used the touchscreen interface presented in Fig. 2-a.

Target Micro-Tasks. We tested four types of micro-tasks asking about domainspecific knowledge: Fish, Flowers, Kanji, and English. Fish and Flowers asked for the name of a pictured fish or flower, which simulated crowdsourced image recognition [START_REF] Bigham | VizWiz: Nearly Real-Time Answers to Visual Questions[END_REF]. Kanji asked for the readings of Chinese characters, simulating part of crowdsourced proofreading of digital books [START_REF] Kobayashi | Age-based Task Specialization for Crowdsourced Proofreading[END_REF]. English asked for the meanings of English words, simulating part of crowdsourced translation [START_REF] Callison-Burch | Fast, Cheap, and Creative: Evaluating Translation Quality Using Amazon's Mechanical Turk[END_REF]. We hypothesized that the senior participants would be better at Fish, Flowers, and Kanji since they have deep knowledge about natural things and their native language from their long experience. We also hypothesized that the younger participants would be better at English since they were working at a global company. The Fish and Flowers types used visual questions while the Kanji and English types used text questions. For all of the four types, we tested multiple-choice answers in the kind of interface shown in Fig. 1-a, where the candidate answers were provided in advance by software or other people. The free-form text input was omitted in this experiment because it is known that text entry on a mobile device is troublesome for the elderly as described in Section 3.2, and our skill assessment model is suitable for multiple-choice tasks as described in Section 3.3. For each of the questions, the experimenters knew the correct answer.

Procedure. Each participant saw 20 different cards for each task type. Thus they each processed (completed or skipped) a total of 80 cards. The presentation order of the cards was balanced. Prior to the tasks, the participants were given a few minutes of instructions on how to perform the tasks. After the participants completed all of the micro-tasks, they then answered several multiple-choice questions that asked for feedback on our framework. Each experimental session took less than 30 minutes for most of the participants.

Results

Task Completion Times. Fig. 3-a shows the average time to complete one task for each task type (skipped cards were excluded from these calculations). We used this measurement to examine whether untrained users could use the card-style interface without confusion. For the senior participants, the overall average values were 10.2, 8.1, 9.3, and 17.7 seconds for Fish, Flowers, Kanji, and English, respectively. For the young participants, the values were 7.2, 7.7, 5.2, and 5.2 seconds. Analysis of variance showed significant main effects for the age (F 1,30.54 =9.59, p<.005) and task type (F 3,2162 =2.96, p<.05). There are also significant interaction effects between the age and task type (F 3,2162 =5.96, p<.001). A post-hoc analysis found that the senior participants were significantly slower than the young participants for Kanji (p<.05) and English (p<.001). There were no significant differences for Fish and Flowers. This indicates that seniors tend to take longer to process text questions, but they are as fast as younger people at visual questions.

Correct Answer Rates. Fig. 3-b shows the percentages of questions answered correctly for each task type. We used this measurement to assess the actual skill levels, which were calculated using knowledge of the correct answers, as a baseline to test the accuracy of our skill estimation mechanism. For the senior participants, the values were 52%, 77%, 61%, and 55% for Fish, Flowers, Kanji, and English, respectively. For the young participants, the values were 48%, 53%, 60%, and 90%. Analysis of variance showed a significant main effect for the task type (F 3,87 =10.64, p<.001). It also showed a significant interaction effect between the age and the task type (F 3,87 =17.77, p<.001). A post-hoc analysis found that the senior participants were significantly better at Flowers than the young participants (p<.001). For English, the young participants significantly outperformed the senior participants (p<.001). The age did not significantly affect the results for Fish and Kanji. Estimated Skill Levels. To confirm that the skill estimation mechanism works, we compared the participants' estimated skills with their actual correct answer rates. Note that the actual rates are often unknown in realistic micro-tasking situations because the ground truths for the micro-tasks might also be unknown.

Fig. 4-a compares the average estimated skill levels for each task type, which were calculated without using knowledge of the correct answers, as described in Section 3.3. For the senior participants, the values were 2.0 × 10 -4 , 4.7 × 10 -1 , 1.2 × 10 -3 , and 1.5 × 10 -1 for Fish, Flowers, Kanji, and English, respectively. For the young participants, the values were 3.4 × 10 -2 , 1.5 × 10 -3 , 3.8 × 10 -4 , and 4.8 × 10 -1 . Analysis of variance showed there was a significant main effect of the task type (F 3,87 =3.94, p<.05). There was also a significant interaction effect between the age and task type (F 3,87 =4.29, p<.01). A post-hoc analysis found that the senior participants had significantly higher skills in Flowers (p<.005) while the young participants had significantly higher skills in English (p<.05). For Fish and Kanji, no significant differences were found. This result matches up well with the actual correct answer rates. This confirms that the differences in skills, at least between the senior and young groups, were correctly detected from the results of the micro-tasks. This indicates that the same mechanism could effectively assess the individual workers. Note that, since the skill levels produced by the probabilistic model are relative values compared to other workers, the absolute values of the skill levels are not known.

The probabilistic model estimates the correct answer by aggregating the answers while considering the estimated skills of the workers. The correct answer rates of the aggregated answers are much higher than the average rates of the individual workers for all of the task types (English: 95.0%, Flowers: 85.0%, Kanji: 85.0%, Fish: 80.0%). This also indicates that the skill levels are estimated successfully. As explained in the Section 3.3, we extended the probabilistic model proposed by Whitehill et al. [START_REF] Whitehill | Whose Vote should Count More? Optimal Integration of Labels from Labelers of Unknown Expertise[END_REF] to support the cases in which workers did not complete, e.g., skipped, some cards. To confirm this extension works, we compared the estimated skills in English for four participants. They completed 20, 11, 9, and 0 English cards, respectively (the first participant skipped no English card while the last one skipped all of the English cards). They did not produce any incorrect answers for the cards they completed. Their estimated English skills were 1.8, 1.9 × 10 -4 , 1.2 × 10 -4 , -2.5 × 10 -4 . The more cards skipped, the lower the estimated skill, as expected.

Subjective Feedback. First we asked "How much would you want to be paid for each card if you were doing this work as a job?" The answers were clearly different between the senior and young groups. More people in the senior group said they were willing to do this work even for free. At the same time, more of the seniors answered they would not work on cards regardless of compensation. This result suggests that seniors were less concerned about the rewards for the micro-tasks.

We then asked "How many cards would you work on in one day?" For this question, about half of the participants answered they could do about 100 cards in one day regardless of age. Finally we asked "Was the system enjoyable?" The majority of participants said that they enjoyed it. In informal post-experiment interviews, several participants commented that they felt the stacked card interface was enjoyable and game-like. The results for the first two questions are shown in Fig. 4-b.

Experiment 2: Live Study

The second experiment sought to test the card-style interface and the skill estimation mechanism in a realistic Web-based setting that involved more practical micro-tasks that would benefit more from the wisdom of age.

Settings

Participants. A total of 28 senior citizens participated in at least one task, with 9 answering the post-experiment questionnaires. For reference, 13 younger people performed at least one task, with 8 answering the questionnaires. The senior participants were members of an experimental local SNS for senior citizens, with no overlap with the participants in the first experiment, but there may have been some overlap with the respondents from the anonymous preliminary survey described in Section 3.1. The younger participants were employees in a global technology company, including four of the earlier participants. None of the participants who answered the questionnaires had prior experience with crowdsourcing, except for one member of the young group. The experiment was conducted in Japanese.

Apparatus. The participants used their own desktop or laptop PC at home or in their workplaces. We used the widget interface shown in Fig. 2-b. For the senior group, the widget was embedded in the portal of the local SNS. For the young group, the widget was embedded in an enterprise SNS for the employees.

Target Micro-Tasks. We tested two types of micro-tasks for proofreading, which is similar to the "fix" and "verify" tasks in Soylent [START_REF] Bernstein | Soylent: A Word Processor with a Crowd Inside[END_REF]. We chose these tasks since linguistic knowledge is known to be an advantage of the elderly [START_REF]Gerontology -Overview and Perspectives, 3rd Ed[END_REF]. Also, our preliminary survey (Section 3.1) suggested that senior citizens are motivated to use their native language skills. The Fix task asked participants to revise a sentence to make it more polite and correct. It first asked whether or not the sentence required any revision, and if the participant answered "yes", then the system asked for a free-form text answer via a card similar to Fig. 1-b. The Verify task asked the participant to choose the more polite and correct sentence from two candidates. It asked for a multiple-choice answer via a card similar to Fig. 1-c. For both types of task, a brief context (e.g., the person who will use the sentence) was included on the card as a note. The scenario assumed that at first some participants would create candidate revisions through the Fix interface, and then other people would make the final decisions through the Verify interface. This experiment is intended to test realistic micro-tasks and the sentences to be proofread were prepared based on actual problems and the correct answers were unknown for each task.

Procedure. Each participant was presented up to 45 and 20 different cards for Fix and Verify tasks, respectively. Thus they completed up to 65 cards at their own pace. The presentation order of the cards was randomized. Prior to the tasks, the senior participants were given a brief explanation of the purpose of this study and instructions on how to perform the tasks. The young participants received an introductory announcement via email or a blog post. After the experiment, they were asked for feedback as in the first experiment. The second experiment ran for approximately one week.

Results

Participation Status. During the experimental period, a total of 42 senior users were shown one or more cards (counted based on the user ID), and 28 of them completed 906 cards in total (mean=32.4, SD=27.4). A total of 387 young users were shown cards (counted based on their IP addresses), and 13 of them completed 104 cards (mean=8.0, SD=11.0). Since 12 of the seniors completed all of the cards for at least in one task type, it seems likely they would have performed more tasks if they were available. None of the young group completed all of the tasks. This might suggest that the card-style interface motivated senior people more than young people, but the relevant experimental conditions were not the same for each group.

Task Completion Times. Fig. 5-a shows the average time to complete one task for each task type (skipped cards and neglected cards, which we defined as cards that took more than 5 minutes to respond to, were excluded from the calculations). For the senior participants, the overall average values were 82.4, 27.5, and 22.1 seconds for Fix-Yes, where they actually fixed the sentence with the free-form text entry card, Fix-No, where they stated that the sentence did not require any revision, and Verify, respectively. For the young participants, the values were 77.9, 45.3, and 29.3 seconds. Note that the value for each trial may be affected by the network delay. Analysis of variance showed significant main effect for the task type (F 2,949 =57.93, p<.001). The age had no significant effect. A post-hoc analysis found that Fix-Yes tasks took significantly longer time than Fix-No and Verify tasks (p<.001).

Estimated Skill Levels.

For the senior participants, the average values of the estimated skill levels were 0.11 and 0.23 for Fix and Verify, respectively. For the young participants, the values were 0.29 and 0.58. Note that the skill levels for Fix were calculated based on the results of the yes-no questions that asked the necessity for revisions. The actual content of revised sentences was ignored in this calculation due to a limitation of our skill assessment model, which cannot work well with open questions.

Analysis of variance showed significant main effect for the age (F 1,44.77 =5.19, p<.05) and task type (F 1,31 =5.18, p<.05). Despite the assumption that senior people would be better at linguistic skills, the young group showed higher skills in this experiment, perhaps because all of the young participants were highly educated and can be expected to have better-than-average linguistic skills. Meanwhile, the effect of the task type seems to be caused by the difference in the percentage of the "skipped" trials (17.1% for Fix, 9.3% for Verify). As confirmed in Section 5.2, skipped trials make the estimated skill lower in our skill assessment model. Fig. 5-b shows the distribution of estimated correct answer rates, calculated by assuming that the aggregated answers are always correct. This indicates that the skill for Fix is not always positively correlated with the skill for Verify (R 2 =.18) and the values are vary widely depending on the worker (SD=.28 for Fix, SD=.18 for Verify). This result suggests that we have to carefully choose skilled workers for each task to insure high-quality results. Subjective Feedback. We asked similar questions as in the first experiment.

Although only some of the participants answered the questions (since this experiment was conducted in a real-world setting), the results seemed to generally confirm the previous results. For the question asking about the compensation, the majority of the senior participants were less concerned about the rewards. The young participants tended to want 5 to 10 yen per card. To the question asking for a number, the participants generally responded that they could do around 100 cards per day. In contrast to the first experiment, many of the participants stated that they would not work on Fix and Verify cards regardless of compensation (50% for seniors, 38% for youths). This might indicate that realistic micro-tasks can involve some unenjoyable work, and thus some additional motivational mechanism would be needed.

Discussion

Based on the experimental results, we discuss the challenges and future work to invite senior citizens to do micro-tasks.

Interface Usability and Acceptability

Overall the results indicated that our approach was adequately usable for and accepted by the target users. The senior participants could understand how to perform all of the types of tasks and complete them with only brief instructions. We also confirmed that the proposed framework worked even in a live situation that involves realistic tasks. However the experimental results also indicated that the performance largely depends on the users and the task types. Since we did not control for the participants' ICT experiences or age-related losses of abilities, further research is needed to discuss the realistic usability and accessibility of our interface for specific users and tasks. We also need to address the range of applications, since the card-style interface basically supports only simple question-answer interactions. Task-decomposition strategies such as discussed by Bernstein et al. [START_REF] Bernstein | Soylent: A Word Processor with a Crowd Inside[END_REF] are promising ways to handle more complex tasks. They tried to assure the quality of their results by using a voting mechanism. As indicated in our second experiment, the mixed use of free-form text and multiple choice cards can support such an answer-vote strategy. Once the task is split into micro-tasks, the question-answer interactions will work well because each micro-task is typically represented as a pair with a simple request and its response. In such cases, multiple choice cards may be preferred and more effective than free-form text cards, i.e., with fewer skips and quicker responses. Some participants suggested that it would be helpful if voice input is available. As we used Web-based implementations, the voice input functions supported by modern Web standards are available.

Skill-based Task Recommendations

Since the elderly are regarded as passive users of ICT, they will not actively explore a pool of tasks to find tasks they like, so our system should offer to the senior workers tasks that fit their skills. The experimental results confirmed that our skill assessment model could assess the differences in skills. This means that once a worker answered several cards for one type of task, the system could assess whether or not the task type is good for that worker. For example, if Alice is better at "fix" and Bob is better at "verify", then the system would provide Alice and Bob with more "fix" and "verify" tasks, respectively. The second experiment indicated that the skills of the elderly vary widely. Even if a worker is better at a type of tasks, it does not necessarily mean the worker is also better at a related, but different type of tasks (e.g., "fix" and "verify" tasks). As the probabilistic approach can estimate workers' skills with a small number of samples, it would allow quickly determining the skills for each specific domain.

A collaborative filtering approach [START_REF] Herlocker | Evaluating Collaborative Filtering Recommender Systems[END_REF] can help recommend task types even when a new worker has never tried those tasks. Our skill estimation mechanism produces a skill profile matrix that can be used for this purpose, where the value of each element represents the skill level of a worker for a task type. We can use a similar approach to Yuen et al.'s work [START_REF] Yuen | TaskRec: Probabilistic Matrix Factorization in Task Recommendation in Crowdsourcing Systems[END_REF], which used a task preference matrix to recommend tasks based on a collaborative filtering mechanism.

Motivation Management

Our experimental results show that seniors did not care much about the monetary rewards. This indicates that we need special care in the design of the incentive mechanism for senior workers. For example, some participants commented that the skill visualization (Fig. 2-c) allowed them to discover that they had greater knowledge in a particular domain, and that motivated them. The motivation may also be affected by the enjoyability. It is worth noting that many of the participants found that the card-style interface was enjoyable and like a game even though we did not intend to include any gamification mechanisms in our framework. However, we also have to note that, in the second experiment, the participants gave less positive feedback than in the first experiment. At this time we cannot conclude whether this resulted from the differences in the participants' communities, in the interfaces (touchscreen vs. desktop widget), or in the task conditions (laboratory vs. realistic), which means further investigation is needed.

Another key to success would be increasing the exposure of senior citizens to micro-tasking opportunities. We believe that the mobile interface and widget interface will be effective for this purpose, as described in Section 4. Also, the card-style interface could be applied to other situations. Some candidate situations include smart TVs, kiosk terminals, vehicle navigation displays, in-flight entertainment systems, and even when waiting in front of a microwave [START_REF] Watanabe | CastOven: A Microwave Oven with Just-in-Time Video Clips[END_REF].

Conclusion

This paper described a framework that aims to increase the participation of senior citizens in various types of micro-tasks with a simple and versatile card-style interface. It uses a probabilistic model to assess their skill profiles, which is necessary for task recommendations and for quality assessments and improvements. The experimental results showed that even untrained seniors could handle micro-tasks by using the card-style interface in both controlled and real-world settings. We also confirmed that the differences in skills can be assessed by analyzing the results of the micro-tasks. We still have challenges to deploy the framework as a platform for senior citizens who want to work. The scope of tasks should be broadened, but more importantly, enjoyment and motivational factors should be evaluated and improved as well as the economic efficiency. We hope that the proposed framework will help senior citizens participate in the workforce and fully utilize their broad experience and knowledge in the society.

Fig. 2 .

 2 Fig. 2. (a) A card on a mobile touchscreen device, (b) A card seen as a widget in a desktop browser, and (c) Estimated skill visualization.

Fig. 3 .

 3 Fig. 3. (a) Task completion times, (b) Actual correct answer rates, by task type with 95% CIs.

Fig. 4 .

 4 Fig. 4. (a) Estimated skills for each task type with 95% CIs, (b) Results of post-experiment questionnaires (100 yen ≈ 1 USD).

Fig. 5 .

 5 Fig. 5. (a) Task completion times for each task type with 95% CIs, (b) Distribution of estimated correct answer rates for each task type.

Acknowledgments. This research was partially supported by the Japan Science and Technology Agency (JST) under the Strategic Promotion of Innovative Research and Development Program.


Danielle Pilcer
email: dpilcer@gmail.com

Andrew Thatcher
email: andrew.thatcher@wits.ac.za

Perceptions of Facebook Privacy and Career Impression Management

Keywords: Facebook, privacy, impression management, employability, social capital theory

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction and Background

Facebook is a platform that has the potential to synthesise all facets of a person"s life in one space [START_REF] Ellison | The benefits of Facebook "friends": Social Capital and college students" use of online social network sites[END_REF]. It allows users to present an overall picture of who they are rather than present a compartmentalised image based on the audience. The content and amount of information users share are within their discretion, however Facebook"s influence, reach and domination of web-based experiences has implications for user"s that are unaware of the exposure they receive on Facebook, especially within the context of their work life. The onus thus lies with the user to be cognisant of their exposure online, the level of accessibility of the content shared, and the potential effects of this shared information on their work image. Facebook has already reared its tentacles in the world of work as a recruitment tool [START_REF] Smith | You"ve been tagged! (Then again, maybe not): Employers and Facebook[END_REF]. Yet in the instance of already employed individuals Facebook can be used by employers, either consciously or unconsciously, to monitor their employee"s activities outside of the office, or screen content that has the potential to place the company or the employee in a negative light [START_REF] Rosenfeld | Responses on computer surveys: Impression management, social desirability, Big Brother Syndrome[END_REF].

Thus, this paper"s line of enquiry is as follows: Is the image one presents of oneself on Facebook fitting for the work context and does one perceive importance and value in presenting self-worth as an employable person. The research questions were as follows: Is there a relationship between how one uses Facebook and how one manages one"s work impressions on Facebook? Is the way in which one uses Facebook and one"s view of Facebook privacy related? Does one"s view of Facebook privacy relate to one"s work impression management on Facebook?

Related Work and Theory

The Social Capital Theory Social Capital Theory reveals that Facebook"s appeal is inherent in its social capital value, that is, the value that is derived from ones" social network [START_REF] Ellison | The benefits of Facebook "friends": Social Capital and college students" use of online social network sites[END_REF]. This social capital is related to indices of psychological wellbeing including self-esteem [START_REF] Ellison | The benefits of Facebook "friends": Social Capital and college students" use of online social network sites[END_REF]. Selfesteem, as a person"s overall self-evaluation of their worth, assumes that all individuals have a vital need to maintain or raise their self-esteem and strive for positive selfpresentations [START_REF] Buys | The impact of privacy on social capital[END_REF]. Translated into Facebook terms, it is expected that the value acquired from Facebook influences a person"s self-esteem positively, which is then emulated in the way the person presents themselves online. That is, the value derived from using Facebook results in a specific image presentation aligned with ones" appraisal of self-worth. Thus, the social value drawn from Facebook will influence the image presented, but both the value and the image will be duly influenced by what Facebook is used for and who makes up one"s audience: who are one"s friends, how many different areas of one"s life make up this group of friends, and how many watching eyes are within this network of friends [START_REF] Mehdizadeh | Self-presentation 2.0: Narcissism and self-esteem on Facebook[END_REF]. Essentially the audience is vital as it supplies the platform from which social value is drawn. In this sense, Facebook architecture is an extension on [START_REF] Foucault | Discipline and Punish[END_REF] imagery of the Panopticon (within a society the effect of constant observation is constant behaviour monitoring by the observed [START_REF] Foucault | Discipline and Punish[END_REF]). Facebook constitutes a society where one is constantly being observed yet in turn constantly observing others too [START_REF] Dunn | Facebook and other social networking sites: Candy-coating surveillance[END_REF]. Thus, there are different categories of users: those that use Facebook to share content, and those who use it to observe. Either grouping of users is subject to the same reality, which sees Facebook allowing large and diverse friend networks requiring monitoring of one"s self-presentation on the basis of the convergence of social contexts (social convergence) [1;8]. However, what constitutes a positive image will not be the same across all social groups.

Facebook Career Impression Management and Privacy

A "socially converged" audience challenges the ability to consciously control selected activities for a desired impression on a particular audience [START_REF] Rosenberg | Online impression management: Personality traits and concerns for secondary goals as predictors of self-presentation tactics on Facebook[END_REF]. That is, selfrepresenting in the Facebook context is not the same as traditional impression management contexts [START_REF] Barash | Faceplant: Impression (Mis)management in Facebook Status Updates[END_REF]. Thus, by drawing from existing theory this paper explores the degree to which the particular audience of the represented self is work-centred. Behaviour monitoring at work is directed at increasing the likelihood of fulfilling financial and social goals, and avoiding possible negative consequences [START_REF] Goffman | The Presentation of Self in Everyday Life[END_REF]. Thus creating and sustaining a desirable image on Facebook suitable for work, assumes that users will monitor their image and activities on Facebook to maintain favourable relations at work, to present the image of an employable person or suitable candidate that is promotion worthy with career advancement prospects, and to avoid possible negative workplace consequences (such as dismissal or disciplinary proceedings).

Behaviour monitoring for a specific audience brings to focus a user"s friend strategy [START_REF] Rosenberg | Online impression management: Personality traits and concerns for secondary goals as predictors of self-presentation tactics on Facebook[END_REF]. A friend strategy is the approach employed when selecting who to add, accept, or reject as a friend. It is concerned with who a person selects to be a part of their network and the selection criteria thereof [START_REF] Debatin | Facebook and Online Privacy: Attitudes, behaviours, and unintended consequences[END_REF]. Strategies range from accepting everybody requesting to accepting only people known personally or face-to-face. The chosen strategy influences what and how much a user presents [START_REF] Boyd | Social network sites: Definition, history and scholarship[END_REF]. Furthermore, "privacy control" as a component of one"s friend strategy sees users determining which parts of their network can access specific information. Users can select different settings, "everybody, friends of friends, friends only", in terms of every wall post, photo tag and status update [START_REF] Liu | Analysing Facebook privacy settings: User expectations vs[END_REF]. Having the ability to select friends and what they can see, facilitates a sense of trust in Facebook and in one"s friend network, thus encouraging and stimulating information disclosure [START_REF] Dwyer | Trust and privacy concern within social networking sites: A comparison of Facebook and MySpace[END_REF].

Facebook"s inherent privacy controversies centre on information exposure to the wrong audience. One"s view of Facebook privacy directs the classification of the wrong audience and the amount of information at this audiences" disposal. How one views Facebook privacy will influence the degree to which privacy is managed, that will in turn affect the quantity and nature of the content shared, the friend strategy employed, and what Facebook is used for.

Instrumentation, Methodology and Results

Within the frame of the Social Capital Theory, a survey was conducted measuring Facebook users" experience, perceptions of privacy and career impression management. This section presents the sample, methods, and measuring instruments.

Participants

The

Procedure and Instruments

An electronic survey link was posted on the researchers" Facebook wall (with a network of 800+ friends) consistently over the 4-week collection period and the link was sent through private inbox messaging. It was posted on different group forums on LinkedIn as well as on the researcher"s profile, and it was tweeted on the researchers" Twitter profile. The link was emailed to all of the researchers" contacts. Lastly, the link was distributed by the Director of the Human Resource Department across the corporate body of a South African based IT company. Ethics Clearance was obtained from the University"s Ethics Committee. The first point of the snowball sample was the researchers" own networks which raises possible biases in sampling. This was addressed by drawing participants from various sources including Facebook, LinkedIn, Twitter, email as well as within a company. Although the data is largely South African and raises possible generalizability concerns.

The survey comprised of a Facebook experience scale, perceptions of Facebook privacy scales (privacy awareness, work privacy, trust) and perceptions of Facebook career impression management scales (self-monitoring, work relations, workplace outcomes). It allowed both users and non-users to participate in the research by framing items in the active and passive form. Non-users scored zero (0) for the Facebook experience scale. This was done to ensure that the whole range of use/non-use was included.

The Facebook experience scale was made up of six items (exemplar: "On average, how many times a day do you use Facebook?"). The perceptions of Facebook privacy scales comprised of three privacy awareness items ("My privacy settings on Facebook are important"); three work privacy items ("It is acceptable for my superior to be my friend on Facebook"); and three trust items ("I trust that my privacy is secure on Facebook"). Facebook career impression management scales were made up of six selfmonitoring items ("I monitor what I post on my Facebook profile"); three work relations items, ("I use my Facebook profile as a work tool, post my current employment, work achievements etc."); and six workplace outcomes items ("I manage my impression on Facebook because I am concerned that it may have negative consequences on my employability"). All the items were scored on a 5-point Likert type scale.

Analysis and Results

An initial pilot study (N=34; age 19-41) validated the developed scales. Cronbach Alphas for the scales were as follows: Facebook experience scale α= 0.91; privacy awareness α=0.72, work privacy α=0.71, trust α=0.78; self-monitoring α= 0.79, work relations α=0.67 and workplace outcomes α=0.83 [START_REF] Cronbach | Essential s of psychological testing[END_REF]. One-way frequencies, Wards Cluster Analysis and Pearson"s Correlation Coefficients were used to explore the nature of the relationships.

 Trends in Usage:

Within the Facebook user sample, 67.37% reported that they had the Facebook application installed on their cell-phone; 65.75% of users reported that they instantly check their notifications; and the period between 12:00-18:00 was reportedly the time of the day Facebook was most used. This period corre-sponds to traditional work hours indicating that Facebook has penetrated and is prevalent in peoples work life by virtue of its reach.  Facebook Friend Strategy: The sample majority reported having less than 400 friends (65.89%), with the most commonly employed strategy (79.37%) being "knowing someone personally" to accept them as a Facebook friend. Furthermore, 84.13% of the sample did not accept friends on the basis of being friends with their friends; 96.3% reported that they will not accept everybody who requests; and 17.46% of participants would accept friends they have heard of through others. Furthermore in terms of privacy controls, 80.63% of participants reported that they were familiar with privacy settings on Facebook; 82.98% reported that they have adjusted their privacy settings with 64.47% adjusting them to friends-of-friends; 55.15% of participants adjusted their settings on the basis of being generally private people, yet 61.05% reported that they did not adjust their settings on initial profile set-up; 14.98% reported that they customized their privacy settings; and only 13.33% of respondents reported that they had adjusted their settings for work related reasons. It is interesting to note that a mere 6.38% had their settings adjusted to "friends only" even though the majority reported that they accepted someone on the basis of knowing someone personally. Furthermore, participant"s network size was correlated negatively with their level of perceived Facebook trust. Results (r= -0.18; p=0.0084) indicated that as network size increased, the level of trust decreased. Although a weak effect size, this finding suggests that a smaller network size has the ability to facilitate trust.  Perceived Social Gains: 67.03% of users reported that Facebook facilitated social interaction.  User Clusters: The cluster analyses conducted identified five groupings of users based on Facebook activities and level of usage. Table 1 presents the clusters and depicts advanced, high, intermediate, low and non-users based on their overall usage. This table illustrates that advanced users were most engaged across the spectrum of Facebook activities. Advanced and high users would be categorized as active users with intermediate and low users being described as passive users.  Correlations Analyses: Pearson"s Correlation Coefficients were conducted to explore the relationships amongst the constructs. All of the relevant conditions for these parametric analyses were met. The results are reported in Table 2.  Users vs. Non-Users: T-tests were conducted to assess the difference between users and non-users in terms of their level of trust. Results (t=4.36; p<0.0001) indicated that non-users (m=10.76) perceive higher Facebook trust than users (m=8.81). This corresponds to the finding that increased Facebook experience is related to decreased Facebook trust. The trends in usage point to Facebook"s position in users" lives and its prevalence in the work context. In terms of friend strategy, the sample majority reported that they had adjusted their privacy settings and had a friend network of less than 400. Correlations indicated that there is increased trust in smaller networks and as network size increased, trust decreased. Non-users have greater trust in Facebook than users, corresponding to the finding that as Facebook experience increases trust decreases. The perceived social gains indicated that participants recognized the social value of Facebook, aligning with the premise of the social capital theory. Users were clustered into five groups indicating that there are varied levels of usage. The correlation analyses, although weak, indicated that there are associations between how one uses Facebook, views privacy, and manages their work impression.

Findings and Discussion

Table 2 shows that although significant relationships found were weak, how one uses Facebook and ones" perceived value in presenting an image of an employable person is influenced by how ones views their Facebook privacy. With greater Facebook experience being related to higher perceptions of self-monitoring and work relation, it is deduced that the more active one is on Facebook the more likely one is to perceive value in monitoring the image of an employable person and using Facebook to manage impressions within existing work relationships. A user will only present an image of themselves that they consider favourable as it facilitates and stimulates the feelings of self-worth [START_REF] Mehdizadeh | Self-presentation 2.0: Narcissism and self-esteem on Facebook[END_REF]. This favourable image aligns with that of a desirable employee. Furthermore greater Facebook experience was related to higher perceptions of trust such that the more active the user the less trusting. Trust can be viewed as the currency of social capital, which is acquired through mutual exchanges and interactions between people [START_REF] Mehdizadeh | Self-presentation 2.0: Narcissism and self-esteem on Facebook[END_REF]. With Facebook stimulating interaction by way of mutual exchanges the way in which Facebook is used and the level of usage influences one"s level of trust. The fostering of trust may also be influenced by one"s friend strategy. "Knowing someone personally" as a pre-requisite for addition to a network allows for a select and limited group of friends, stimulates greater trust within this network. Perceiving greater trust could also be influenced by one"s network size, such that smaller networks facilitate a more trusting environment as exposure is more limited (majority of respondents friend networks were less than 400). Even though the majority of users did not limit their settings to friends only, having the ability to select who can access shared content builds trust.

One"s perceptions of self-monitoring and workplace outcomes were related to low levels of privacy awareness (Table 2). That is, monitoring activities to present the image of an employable person and believing that Facebook can have real workplace outcomes are related to decreased levels of privacy protection and information disclosure. In this way, impression management is related to decreased disclosure of information as shared content is selected and managed on the basis of presenting the specified image. This shows that how one views their privacy online ultimately affects how much information is shared and how impressions are managed.

High levels of work privacy were related to low levels of perceived work relations. Believing that work-associated people should not form part of one"s friend network as employers monitor activities is related to low levels of using Facebook as a work tool. Thus having a network that is free from work-associated people means that profiles do not have to be managed in line with work. Furthermore, high levels of work privacy were associated with high levels of perceptions of workplace outcomes. The belief that employers utilise Facebook to monitor employees is aligned with perceiving that Facebook can affect ones potential for promotion, career developments and possible dismissal or disciplinary action. Viewing privacy in this way will affect what information is shared and how it is managed in order to emulate the image of an employable person. In conclusion, the focus and findings of this paper explored the nature of relationships that have a direct effect on work practices and people"s lives. Facebook users who recognise the link between their work and Facebook lives derive social value from Facebook and simultaneously appreciate the value in presenting a favourable work image online.

Table 1 .

 1 User Cluster Proportions

	Users (%)

Table 2 .

 2 Pearson"s R Correlation Matrix (* Significant at ρ<0.05)