Theories on social learning indicate that imitative choices are usually performed whenever copying the others' behaviour has no additional cost. Here, we extended such investigations of social learning to Human-Robot Interaction (HRI). Participants played the Economic Investment Game with a robot banker while observing another robot player also investing in the robot banker. By manipulating the robot banker payoff, three conditions of unfairness were created: (1) unfair payoff for the participants, (2) unfair payoff for the robot player and (3) unfair payoff for both. Results showed that when the payoff was low for the participants and high for the robot player, participants invested more money in the robot banker than when both parties received a low return. Also, for this specific condition, participants' investments increased further with a more interactive robot player (defined as demonstrating increased attention, congruent movements and speech) This suggests that social and cognitive human competencies can be used and transposed to non-human agents. Further, imitation can potentially be extended to HRI, with interactivity likely having a key role in increasing this effect.

We investigated the perceived credibility of statements made by robots, hypothesising that people are more likely to believe robots with humanlike characteristics than those that are less anthropomorphic. We also examined whether prior experience with a humanlike robot would lead people to extend this advantage to the less-anthropomorphic robot. A measure of credibility was provided by agreement on the pricing of objects, where participants negotiated with either a more (iCub) or less-anthropomorphic robot (Scitos G5) that was engaged in more (using social gaze) or less-humanlike (fixed gaze) social behaviour. In the first experiment participants only interacted with Scitos G5, in the second they interacted with Scitos G5 only after having first interacted iCub. Results showed that iCub was more credible than Scitos G5, and was the only robot to benefit from the use of social gaze. It was also found that the credibility of the Scitos G5 was higher after participants were `primed' by prior exposure to the iCub.