Observation and imitation of actions performed by humans, androids, and robots : an EMG study

Understanding others’ actions is essential for functioning in the physical and social world. In the past two decades research has shown that action perception involves the motor system, supporting theories that we understand others’ behavior via embodied motor simulation. Recently, empirical approach to action perception has been facilitated by using well-controlled artificial stimuli, such as robots. One broad question this approach can address is what aspects of similarity between the observer and the observed agent facilitate motor simulation. Since humans have evolved among other humans and animals, using artificial stimuli such as robots allows us to probe whether our social perceptual systems are specifically tuned to process other biological entities. In this study, we used humanoid robots with different degrees of human-likeness in appearance and motion along with electromyography (EMG) to measure muscle activity in participants’ arms while they either observed or imitated videos of three agents produce actions with their right arm. The agents were a Human (biological appearance and motion), a Robot (mechanical appearance and motion), and an Android (biological appearance and mechanical motion). Right arm muscle activity increased when participants imitated all agents. Increased muscle activation was found also in the stationary arm both during imitation and observation. Furthermore, muscle activity was sensitive to motion dynamics: activity was significantly stronger for imitation of the human than both mechanical agents. There was also a relationship between the dynamics of the muscle activity and motion dynamics in stimuli. Overall our data indicate that motor simulation is not limited to observation and imitation of agents with a biological appearance, but is also found for robots. However we also found sensitivity to human motion in the EMG responses. Combining data from multiple methods allows us to obtain a more complete picture of action understanding and the underlying neural computations

Affect, Value and Choice : How Incidental Affect Influences Decisions

Everyday decisions are never made in a void -- a busy environment surrounds a decision maker as he or she makes a choice. Previous research has clearly demonstrated that unrelated factors, specifically incidental affect, can influence decisions, often in an unwanted and unnoticed manner (Wilson & Brekke, 1994). However, there has yet to be a systematic examination of the influence of incidental affect on decision-making processes. This dissertation explores the effects of incidental affective stimuli on financial decisions. Through this work I aimed to demonstrate global effects across stimuli categories, characterize the type of decisions susceptible to influence, and uncover insights on the process through which affect is incorporated into decision making processes, specifically valuation. Chapter 1 presents 3 studies that demonstrated robust evidence for the influence of incidental affective pictures on gamble decisions. We found that affective stimuli drive predictable changes in gamble acceptance, and that affective reactions to the pictures mediate this effect. Our results further show that affect influences choice indirectly, by altering valuation parameters such as loss aversion, and that these effects specifically target gambles that are ambiguous in value. These findings have important implications for integrating affect into models of financial choice. Chapter 2 examined more closely the relation between affect and valuation, through a motivation framework. Using a paradigm that paired different types of affective judgments and approach/ avoidance response tendencies, we found that hedonic 'liking' judgments differed from 'wanting' judgments (judgments of motivational value) across genders, in their susceptibility to motivational state, and finally in their relation to approach/avoidance actions. Bridging the data from both studies through a combined analysis demonstrated evidence that 'wanting' judgments were more broadly predictive of gamble acceptance, than 'liking' judgments. These findings support the hypothesis that incentive evaluations transfers from incidental reactions into decision valuation calculations, thus influencing choic

Bridging the mechanical and the human mind : spontaneous mimicry of a physically present android

The spontaneous mimicry of others' emotional facial expressions constitutes a rudimentary form of empathy and facilitates social understanding. Here, we show that human participants spontaneously match facial expressions of an android physically present in the room with them. This mimicry occurs even though these participants find the android unsettling and are fully aware that it lacks intentionality. Interestingly, a video of that same android elicits weaker mimicry reactions, occurring only in participants who find the android “humanlike.” These findings suggest that spontaneous mimicry depends on the salience of humanlike features highlighted by face-to-face contact, emphasizing the role of presence in human-robot interaction. Further, the findings suggest that mimicry of androids can dissociate from knowledge of artificiality and experienced emotional unease. These findings have implications for theoretical debates about the mechanisms of imitation. They also inform creation of future robots that effectively build rapport and engagement with their human users