In the present experiment, we investigated how robots' social category membership and characteristics of an HRI task affect humans' evaluative and behavioral reactions toward robots. Participants (N = 38) played a card game together with two robots, one belonging to participants' social in-group and the other one being a social out-group member. Furthermore, participants were either asked to cooperate with the in- and to compete with the out-group robot (congruent condition), or they were asked to cooperate with the out-group robot while competing with the in-group robot (incongruent condition). The results largely support our hypotheses: Participants showed more positive evaluative reactions toward the in-group (vs. the out-group) robot and they anthropomorphized it more strongly, independent of the congruency or incongruence of the HRI. Moreover, if required, participants cooperated with both the in- and the out-group robot, whereas their cooperativeness was more pronounced toward the in-group robot. Finally, participants indicated more difficulties with the HRI in the incongruent vs. the congruent condition. The theoretical and practical implications of the findings are discussed.

In an experiment, we tested whether anthropomorphism would reduce psychological stress associated with human-robot interactions (HRI). Participants anticipated (vs. did not anticipate) an interaction with a humanlike versus machinelike robot type, and their electrodermal activity (EDA), a physiological indicator of psychological stress, was measured. Results indicate that anticipating an HRI increased psychological stress independent of robot type.

Empathy plays an important role in the interaction between humans and robots. The contagious effect of yawning is moderated by the degree of social closeness and empathy. We propose to analyse the contagion of yawns as an indicator for empathy. We conducted pilot studies to test different experimental procedures for this purpose. We hope to be able to report on experimental results in the near future.

In an experiment we manipulated a robot's voice in two ways: First, we varied robot gender; second, we equipped the robot with a human-like or a robot-like synthesized voice. Moreover, we took into account user gender and tested effects of these factors on human-robot acceptance, psychological closeness and psychological anthropomorphism. When participants formed an impression of a same-gender robot, the robot was perceived more positively. Participants also felt more psychological closeness to the same-gender robot. Similarly, the same-gender robot was anthropomorphized more strongly, but only when it utilized a human-like voice. Results indicate that a projection mechanism could underlie these effects.

A recent theoretical framework on anthropomorphism emphasizes the role of elicited agent knowledge in anthropomorphic inferences about nonhuman entities. According to the Three-Factor Model of psychological Anthropomorphism, people use anthropocentric knowledge structures when judging unfamiliar objects (e.g., robots). In the present research, our goal was to manipulate the accessibility of such elicited agent knowledge by varying features of a robot's voice: Specifically, we examined effects of vocal cues that reflected both gender of robot (i.e., a male vs. female voice) and voice type (i.e., a human-like vs. robot-like voice). This was done to test the impact of these vocal features on anthropomorphic inferences about the robot and on human-robot interaction (HRI) acceptance. Our results demonstrate that a robot's vocal cues clearly influence subsequent judgments of the robot and particularly so, when participant gender taken into account. Implications of our research for robotics will be discussed.

In the present study, we experimentally investigated whether the mental simulation of an interaction with the robot NAO would improve human-robot interaction (HRI) acceptance, and would reduce negative attitudes and anxiety toward robots in general. Participants were introduced to the robot NAO and were then instructed to imagine for two minutes either a cooperative or a competitive interaction with the robot or a neutral scenario that did not include an HRI. Our results showed that, independent of its content, imagining contact with NAO improved HRI acceptance. Moreover, after imagining contact with the robot, participants indicated less negative attitudes and less anxiety toward robots in general. These effects were strongest for cooperative imagined contact. Theoretical and practical implications for research on HRI will be discussed.

Recent research has shown that anthropomorphism represents a means to facilitate HRI. Under which conditions do people anthropomorphize robots and other nonhuman agents? This research question was investigated in an experiment that manipulated participants' anticipation of a prospective human-robot interaction (HRI) with a robot whose behavior was characterized by either low or high predictability. We examined effects of these factors on perceptions of anthropomorphism and acceptance of the robot. Innovatively, the present research demonstrates that anticipation of HRI with an unpredictable agent increased anthropomorphic inferences and acceptance of the robot. Implications for future research on psychological determinants of anthropomorphism are discussed.

In an experiment we empirically tested one key determinant of Epley's Three-Factor Theory of Anthropomorphism: Specifically, we investigated the interplay of both dispositional and situational facets of effectance motivation in predicting anthropomorphic inferences about the robot NAO. That is, we manipulated the predictability of the robot's behavior and whether participants anticipated an interaction with NAO. Innovatively, we also examined interindividual differences in participants' desire for control, a dispositional aspect of effectance motivation. Taken together, we go beyond previous work by (1) increasing ecological validity of the experimental setting; by (2) extending the range of measures to assess anthropomorphism, and by (3) examining the role of contextual and dispositional components of effectance motivation for anthropomorphism. Because this is the first work to study the interplay between these factors, our work contributes to a better theoretical and empirical understanding of psychological anthropomorphism.