Research suggests smartphone users face "application overload", but literature lacks an in-depth investigation of how users manage their time on smartphones. In a 3-week study we collected smartphone application usage patterns from 21 participants to study how they manage their time interacting with the device. We identified events we term application micro-usage: brief bursts of interaction with applications. While this practice has been reported before, it has not been investigated in terms of the context in which it occurs (e.g., location, time, trigger and social context). In a 2-week follow-up study with 15 participants, we captured participants' context while micro-using, with a mobile experience sampling method (ESM) and weekly interviews.Our results show that about approximately 40% of application launches last less than 15 seconds and happen most frequently when the user is at home and alone. We further discuss the context, taxonomy and implications of application micro-usage in our field. We conclude with a brief reflection on the relevance of short-term interaction observations for other domains beyond mobile phones.

Social conformity occurs when an individual changes their behaviour in line with the majority's expectations. Although social conformity has been investigated in small group settings, the effect of gender -of both the individual and the majority/minority -is not well understood in online settings. Here we systematically investigate the impact of groups' gender composition on social conformity in online settings. We use an online quiz in which participants submit their answers and confidence scores, both prior to and following the presentation of peer answers that are dynamically fabricated. Our results show an overall conformity rate of 39%, and a significant effect of gender that manifests in a number of ways: gender composition of the majority, the perceived nature of the question, participant gender, visual cues of the system, and final answer correctness. We conclude with a discussion on the implications of our findings in designing online group settings, accounting for the effects of gender on conformity.CCS Concepts: • Human-centered computing → Empirical studies in collaborative and social computing; Empirical studies in HCI .

Substantial ongoing research now uses smartphones as a research platform for various studies and interventions. With the ageing population becoming a frequent focus of needed research, an increasing number of studies and projects attempt to develop technological interventions for the elderly population. Yet, it is not clear exactly how widespread is the adoption and use of smartphones amongst seniors. Many studies acknowledge that today's elders are not particularly keen on using smartphones, but in the near future we can expect this trend to change. In this paper we present an in-depth survey of statistics on smartphone adoption within the elder population, and describe both the popularity and type of use that smartphones enjoy amongst elders. We show that far from being ubiquitous, smartphones are still overshadowed by traditional feature phones today, and substantial geographical differences also do exist between countries. Furthermore, those seniors who do adopt smartphones tend to use them as feature phones, and do not adopt services that are popular amongst younger users. Our survey provides an assessment on the ubiquity of smartphones amongst seniors, that can be used to inform the assumptions of our research community.

Research is increasingly highlighting the potential for situated crowdsourcing to overcome some crucial limitations of online crowdsourcing. However, it remains unclear whether a situated crowdsourcing market can be sustained, and whether worker supply responds to pricesetting in such a market. Our work is the first to systematically investigate workers' behaviour and response to economic incentives in a situated crowdsourcing market. We show that the market-based model is a sustainable approach to recruiting workers and obtaining situated crowdsourcing contributions. We also show that the price mechanism is a very effective tool for adjusting the supply of labour in a situated crowdsourcing market. Our work advances the body of work investigating situated crowdsourcing.

Researchers who analyse smartphone usage logs often make the assumption that users who lock and unlock their phone for brief periods of time (e.g., less than a minute) are continuing the same "session" of interaction. However, this assumption is not empirically validated, and in fact different studies apply different arbitrary thresholds in their analysis. To validate this assumption, we conducted a field study where we collected user-labelled activity data through ESM and sensor logging. Our results indicate that for the majority of instances where users return to their smartphone, i.e., unlock their device, they in fact begin a new session as opposed to continuing a previous one. Our findings suggest that the commonly used approach of ignoring brief standby periods is not reliable, but optimisation is possible. We therefore propose various metrics related to usage sessions and evaluate various machine learning approaches to classify gaps in usage.