Ber Boris de Ruyter

Adaptive Persuasive Systems: A Study of Tailored Persuasive Text Messages to Reduce Snacking

This article describes the use of personalized short text messages (SMS) to reduce snacking. First, we describe the development and validation (Nu2009=u2009215) of a questionnaire to measure individual susceptibility to different social influence strategies. To evaluate the external validity of this Susceptibility to Persuasion Scale (STPS) we set up a two week text-messaging intervention that used text messages implementing social influence strategies as prompts to reduce snacking behavior. In this experiment (Nu2009=u200973) we show that messages that are personalized (tailored) to the individual based on their scores on the STPS, lead to a higher decrease in snacking consumption than randomized messages or messages that are not tailored (contra-tailored) to the individual. We discuss the importance of this finding for the design of persuasive systems and detail how designers can use tailoring at the level of social influence strategies to increase the effects of their persuasive technologies.

Can You Be Persuaded? Individual Differences in Susceptibility to Persuasion

Persuasive technologies are growing in popularity and many designers create systems which intentionally change users attitudes or behaviors. This study shows that peoples individual differences in susceptibility to persuasion, as implemented using the six persuasion principles proposed by Cialdini 2, relates to their compliance to a persuasive request which is accompanied by a persuasive cue. This result is a starting point for designers to start incorporating individual differences in susceptibility to persuasive cues in their adaptive persuasive systems.

Investigating Privacy Attitudes and Behavior in Relation to Personalization

This article presents an experimental study of privacy-related attitudes and behaviors regarding a music recommender service based on two types of user modeling: personality traits and musical preferences. Contrary to prior expectations and attitudes reported by participants, personality traits are frequently disclosed to the system and other users, indicating that embedded modeling of user personality does not represent an acceptance barrier. Discrepancies between privacy attitudes and behaviors have been reported before in the context of e-commerce applications, but the corresponding studies could not exclude several conflicting hypotheses, such as participants expressing attitudes outside the context of specific privacy dilemmas and contact with researchers, which may have mitigated perceived privacy risks. Arguably, these are fundamental problems in empirical investigations into privacy that apply to most published works relating to privacy and user modeling. Measures to control these factors in this study are discussed, and methodological suggestions for future research are presented.

Reconexp: a way to reduce the data loss of the experiencing sampling method

This paper presents Reconexp, a diary method supported by a distributed application, which partly runs on a mobile device and partly on a website, enabling us to survey user attitudes, experiences and requirements in field studies. Reconexp combines aspects of the Experience Sampling Method and the Day Reconstruction Method aiming to reduce data loss, improve data quality and reduce burden put upon participants. We discuss our first experiences of using this method in the context of a study of communication needs of working parents with young children.

Addressing interpersonal communication needs through ubiquitous connectivity: Home and away

This paper describes a user study regarding the human need to stay in touch with closely related people. The study was a combination of interviews and diaries. This user needs analysis has informed the design of a novel end-to-end communication system for helping closely related people, who are spread geographically, to stay in touch. The design concept is described in brief, followed by a summary of ongoing implementation and assessment work.

Sharing experiences through awareness systems in the home

In the current paper we hypothesize that providing peripheral awareness information to remotely located but socially close individuals will yield affective user benefits. An experiment in a controlled home-like environment was conducted to investigate the effects of providing different levels of peripheral awareness information on these affective benefits. In the experiment peripheral awareness aimed to support groups of friends to jointly watch a soccer match at remote locations. The experiment has shown that providing awareness information increases the social presence and the group attraction felt by individuals towards their remote partners. The experiment has provided concrete quantitative and qualitative evidence for the hypothesized benefits of supporting primary relationships through awareness systems and of the relevance of social presence as a requirement in the design of peripheral awareness displays.

EZ phone: persuading mobile users to conserve energy

El metodo de muestreo por conglomerados puede utilizarse para llevar a cabo la evaluacion rapida de las necesidades de salud y de otro tipo en comunidades afectadas por desastres naturales. El metodo, que se basa en el modelo usado por el Programa Ampliado de Inmunizacion de la OMS para estimar la cobertura con vacunacion, ha sido modificado para que proporcione 1) estimaciones de la poblacion que queda en una zona determinada y 2) estimaciones del numero de personas con necesidades especificas en la zona que ha sido afectada por un desastre. Este enfoque difiere del que se ha usado anteriormente a raiz de otros desastres en que las evaluaciones rapidas de las necesidades solo han consistido en estimar la proporcion de la poblacion con necesidades especificas. Aqui se propone un diseno de encuesta modificado que se basa en el uso de n x k para calcular la poblacion restante, la gravedad del dano, la proporcion y el numero de personas con necesidades especificas, el numero de domicilios danados o destruidos y los cambios que sufren estas estimaciones en determinado periodo como parte de la encuesta.

Inducing sadness and anxiousness through visual media: Measurement techniques and persistence

The persistence of negative moods (sadness and anxiousness) induced by three visual Mood Induction Procedures (MIP) was investigated. The evolution of the mood after the MIP was monitored for a period of 8 min with the Self-Assessment Manikin (SAM; every 2 min) and with recordings of skin conductance level (SCL) and electrocardiography (ECG). The SAM pleasure ratings showed that short and longer film fragments were effective in inducing a longer lasting negative mood, whereas the negative mood induced by the IAPS slideshow was short lived. The induced arousal during the anxious MIPs diminished quickly after the mood induction; nevertheless, the SCL data suggest longer lasting arousal effects for both movies. The decay of the induced mood follows a logarithmic function; diminishing quickly in the first minutes, thereafter returning slowly back to baseline. These results reveal that caution is needed when investigating the effects of the induced mood on a task or the effect of interventions on induced moods, because the induced mood diminishes quickly after the mood induction.

Lighting to make you feel better: Improving the mood of elderly people with affective ambiences

Current lighting technologies extend the options for changing the appearance of rooms and closed spaces, as such creating ambiences with an affective meaning. Using intelligence, these ambiences may instantly be adapted to the needs of the room’s occupant(s), possibly improving their well-being. We hypothesized that ambiences with a clearly recognizable, positive affective meaning could be used to effectively mitigate negative mood in elderly. After inducing a sad mood with a short movie one group of elderly was immersed in a positive high arousing (i.e., activating) ambience, and another group in a neutral ambience. Similarly, after inducing anxiety with a short movie one group of elderly was immersed in a pleasant low arousing (i.e., cozy) ambience, and another group in a neutral ambience. We monitored the evolution of the mood of the four groups of elderly over a period of ten minutes after the mood induction, with both self-reported mood measurements (every 2 minutes) and constant measurements of the skin conductance response (SCR) and electrocardiography (ECG). In line with our hypothesis we found that the activating ambience was physiologically more arousing than the neutral ambience. The cozy ambience was more effective in calming anxious elderly than the neutral ambience, as reflected by both the self-reported and physiological measurements.

On the relative importance of privacy guidelines for ambient health care

We present an empirical study regarding the relative importance of complying with privacy related guidelines in the context of a Health Monitoring System. Participants were confronted with text scenarios describing privacy related aspects of a health monitoring service for daily use at home. Participants assessed the relative importance to them of simplified variants of the OECD (Organization of Economic Cooperation and Development) guidelines for the protection of personal data. The guidelines that relate to Insight and Openness were most valued. The guidelines relating to Modification and Data Quality were valued least by most participants in this context. Methodological challenges were encountered on the way, which reveal the complexity of conducting empirical investigations of privacy aspects of human-computer interaction.