Yoshimasa Tawatsuji

Qualitative Model for Neuro-Functional Mechanism Inducing Human Error Detection to Humanlike Agents Based on Cortico-Cerebellar Function

The uncanny valley is a major phenomenon that occurs during the implementation of facial expressions in a humanlike agent. Recent studies have explained that the negative impression of the agent’s expressions is a “prediction error.” We hypothesized that the prediction error stemmed from the differential output of dual processing, - that is, emotional and rational processing, - and it negatively affected a person’s impression of the facial expression of the agent, which was similar to that when perceiving an eerie sensation. A qualitative computational model was proposed to clarify this mechanism according to cortico-cerebellar function to compute the prediction of the humanlike agent’s facial movement. Thus, rapid emotional processing was indispensable with the thalamus playing an essential role in the processing.

An experimental study on the effect of repeated exposure of facial caricature on memory representation of a model’s face

Why does human can identify a facial caricature with its model’s face? We hypothesize that a facial caricature has an effect on a person’s memory representation of the model’s face to get closer into the facial caricature itself, which causes a person to evoke the feeling of similarity between the model’s face and its facial caricature. In this point, we conducted the experiment to verify whether the continuous exposure of a facial caricature changes participants’ memory representation and whether the exposure also evokes participants’ feeling of similarity between them.

Proposal for the Model of Occurrence of Negative Response toward Humanlike Agent Based on Brain Function by Qualitative Reasoning

For designing the rounded communication between human and agent, humanlike appearance of agent can contribute to human understandability towards their intension. However, the excessive humanlike-ness can cause human to feel repulsive against the agent, which is well known as the uncanny valley. In this study, we propose a model providing an explanation for how the human negative response is fomred, based on the brain regions and its function, including the amygdala, hippocampus, cortex and striatum. This model is described with quantitative reasoning and simulated. The results indicate that as human observes a humanlike agent, the emotion goes negative and the brain regions were more activated in comparison with the case human observes a person.

Experimental study toward modeling of the uncanny valley based on eye movements on human/non-human faces

In the research field of human-agent interaction, it is a crucial issue to clarify the effect of agent appearances on human impressions. The uncanny valley is one crucial topic. We hypothesize that people can perceive a humanlike agent as human at an earlier stage in interaction even if they finally notice it as non-human and such contradictory perceptions are related to the uncanny valley. We conducted an experiment where participants were asked to judge whether faces presented on a PC monitor were human or not. The faces were a doll, a CG-modeled human image fairly similar to real human, an android robot, another image highly similar and a person. Eyes of the participants were recorded during watching the faces and changes in observing the faces were studied. The results indicate that eye data did not initially differ between the person and CG fairly similar, whereas differences emerged after several seconds. We then proposed a model of the uncanny valley based on dual pathway of emotion.