Jaap Ham

Ambient persuasive technology needs little cognitive effort: the differential effects of cognitive load on lighting feedback versus factual feedback

Persuasive technology can influence behavior or attitudes by for example providing interactive factual feedback about energy conservation. However, people often lack motivation or cognitive capacity to consciously process such relative complex information (e.g., numerical consumption feedback). Extending recent research that indicates that ambient persuasive technology can persuade the user without receiving the user’s conscious attention, we argue here that Ambient Persuasive Technology can be effective while needing only little cognitive resources, and in general can be more influential than more focal forms of persuasive technology. In an experimental study, some participants received energy consumption feedback by means of a light changing color (more green=lower energy consumption, vs. more red=higher energy consumption) and others by means of numbers indicating kWh consumption. Results indicated that ambient feedback led to more conservation than factual feedback. Also, as expected, only for participants processing factual feedback, additional cognitive load lead to slower processing of that feedback. This research sheds light on fundamental characteristics of Ambient Persuasive Technology and Persuasive Lighting, and suggests that it can have important advantages over more focal persuasive technologies without losing its persuasive potential.

Cross-cultural study on human-robot greeting interaction : acceptance and discomfort by Egyptians and Japanese

Abstract As witnessed in several behavioural studies, a complex relationship exists between people’s cultural background and their general acceptance towards robots. However, very few studies have investigated whether a robot’s original language and gesture based on certain culture have an impact on the people of the different cultures. The purpose of this work is to provide experimental evidence which supports the idea that humans may accept more easily a robot that can adapt to their specific culture. Indeed, improving acceptance and reducing discomfort is fundamental for future deployment of robots as assistive, health-care or companion devices into a society. We conducted a Human- Robot Interaction experiment both in Egypt and in Japan. Human subjects were engaged in a simulated video conference with robots that were greeting and speaking either in Arabic or in Japanese. The subjects completed a questionnaire assessing their preferences and their emotional state, while their spontaneous reactions were recorded in different ways. The results suggest that Egyptians prefer the Arabic robot, while they feel a sense of discomfort when interacting with the Japanese robot; the opposite is also true for the Japanese. These findings confirm the importance of the localisation of a robot in order to improve human acceptance during social human-robot interaction.

Trusting digital chameleons: the effect of mimicry by a virtual social agent on user trust

Earlier research suggested that mimicry increases liking and trust in other people. Because people respond socially to technology and mimicry leads to increased liking of virtual agents, we expected that a mimicking virtual agent would be liked and trusted more than a non-mimicking one. We investigated this expectation in an automotive setting. We performed an experiment in which participants played an investment game and a route planner game, to measure their behavioral trust in two virtual agents. These agents either mimicked participant’s head movements or not. Liking and trust of these virtual agents were measured with questionnaires. Results suggested that for the investment game, mimicry did not increase liking or trust. For the route planner game however, a mimicking virtual agent was liked and trusted more than a non-mimicking virtual agent. These results suggest that mimicry could be a useful tool to persuade users to trust a virtual agent.

The dominant robot: threatening robots cause psychological reactance, especially when they have incongruent goals

Persuasive technology can take the form of a social agent that persuades people to change behavior or attitudes. However, like any persuasive technology, persuasive social agents might trigger psychological reactance, which can lead to restoration behavior. The current study investigated whether interacting with a persuasive robot can cause psychological reactance. Additionally, we investigated whether goal congruency plays a role in psychological reactance. Participants programmed a washing machine while a robot gave threatening advice. Confirming expectations, participants experienced more psychological reactance when receiving high-threatening advice compared to low-threatening advice. Moreover, when the robot gave high-threatening advice and expressed an incongruent goal, participants reported the highest level of psychological reactance (on an anger measure). Finally, high-threatening advice led to more restoration, and this relationship was partially mediated by psychological reactance. Overall, results imply that under certain circumstances persuasive technology can trigger opposite effects, especially when people have incongruent goal intentions.

What makes social feedback from a robot work? disentangling the effect of speech, physical appearance and evaluation

Previous research showed that energy consumption feedback of a social nature resulted in less energy consumption than factual energy consumption feedback. However, it was not clear which elements of social feedback (i.e. evaluation of behavior, the use of speech or the social appearance of the feedback source) caused this higher persuasiveness. In a first experiment we studied the role of evaluation by comparing the energy consumption of participants who received factual, evaluative or social feedback while using a virtual washing machine. The results suggested that social evaluative feedback resulted in lower energy consumption than both factual and evaluative feedback. In the second experiment we examined the role of speech and physical appearance in enhancing the persuasiveness of evaluative feedback. Overall, the current research suggests that the addition of only one social cue is sufficient to enhance the persuasiveness of evaluative feedback, while combining both cues will not further enhance persuasiveness.

A persuasive robotic agent to save energy: the influence of social feedback, feedback valence and task similarity on energy conservation behavior

In this paper we explore the persuasive effects of social feedback provided by a robotic agent, on behavioral change. In lab experiments, participants had the opportunity to conserve energy while carrying out washing tasks with a simulated washing machine. Three experiments tested the effect of positive and negative social feedback and compared these effects to more widely used factual feedback. Results of these studies indicate that social feedback has stronger persuasive effects than factual feedback (Experiment 1) and factual-evaluative feedback (Experiment 2). In addition, an effect of feedback valence was found, demonstrating more conservation actions following negative feed-back (social or factual) as compared to positive feedback. Interestingly, especially negative social feedback had the strongest persuasive effects (Experiment 1, 2, & 3), and task similarity enhanced the effects of negative feedback (Experiment 3). These findings have several implications for theory and design of persuasive robotic agents.

Introducing a rasch-type anthropomorphism scale

In human-robot interaction research, much attention is given to the extent to which people perceive humanlike attributes in robots. Generally, the concept anthropomorphism is used to describe this process. Anthropomorphism is defined in different ways, with much focus on either typical human attributes or uniquely human attributes. This difference has caused different measurement tools to be developed. We argue that anthropomorphism can best be described as a continuum ranging from low to high human likeness, and should be measured accordingly. We found that anthropomorphic characteristics can be invariantly ordered according to the ease with which these can be ascribed to robots.

Preface to the special issue on personalization and behavior change

Digital behavior intervention is a growing area of research which investigates how interactive systems can encourage and support people to change their behavior. Personalization plays an important role in this, as the most effective persuasive and motivational strategies are likely to depend on user characteristics such as the user’s personality, affective state, existing attitudes, behaviors, knowledge, and goals. Example application areas include healthcare (e.g., encouraging people to eatmore healthily and exercise more), education (e.g., motivating learners to study more), environment (e.g., encouraging people to use less energy and more public transport), and collaborative content development (e.g., incentivizing people to annotate resources). The idea that a system may be used to motivate people on the basis of a user model is certainly not novel. As early as the 1980s, intelligent tutoring systems encouraged students to learn by means of tailored feedback and hints (Sleeman and Brown 1982), and in the 90s patient education systems attempted to address compliance to a medical regimen by means of information and personalized advice (De Carolis et al. 1996) or encouraged people to adopt healthier lifestyles (Reiter et al. 2003). However, it is only recently that a number of seemingly non correlated, extensive research efforts,

Persuasive power in groups: the influence of group feedback and individual comparison feedback on energy consumption behavior

In this paper we argue that energy conservation is largely a group phenomenon requiring group interventions to achieve change. Persuasive technology can help to provide these interventions. The present study explores the influence of group feedback and individual comparative feedback on energy consumption using an experimental simulation paradigm. To account for cultural differences in group orientation and the power of group feedback, two studies were conducted, one in the Netherlands and one in Japan, in which groups of participants received feedback on everyday tasks. As expected, Dutch participants saved more energy when individual comparison feedback was present, but not the Japanese participants. In contrast, as expected, group feedback caused Japanese participants to save more energy. Providing solely group feedback did not promote energy saving in the Netherlands. Group feedback made the Dutch save more energy only in combination with individual comparison feedback. These results suggest that persuasive technology can employ the power of feedback as a group intervention, but that relevant cultural orientations are crucial.

Investigating the Effect of Relative Cultural Distance on the Acceptance of Robots

A complex relationship exists between people’s cultural background and their general acceptance towards robots. Previous studies supported the idea that humans may accept more easily a robot that can adapt to their specific culture. However, it is not clear whether between two robots which are identified as foreign robots because of their verbal and non-verbal expressions, the one that is culturally closer may be preferred or not. In this experiment, participants of Dutch nationality were engaged in a simulated video conference with a robot that is greeting and speaking either in German or in Japanese; they completed a questionnaire assessing their preferences and their emotional state. As Dutch participant showed less signs of discomfort and better acceptance when interacting with a German robot, the hypothesis that acceptance of a robot could be directly proportional to cultural closeness was supported, while the hypothesis that similar foreign robots are equally less accepted regardless of the countrywas rejected. Implications are discussed for how robots should be designed to be employed in different countries.