Haruaki Fukuda

Interaction with a Moving Object Affects One’s Perception of Its Animacy

Sometimes we regard just an artifact as a lifelike one and other times not; it is considered to depend on how we deal and interact with the artifact. We experimentally examined whether differences in the manner of interacting with a moving robot (operating it or only observing its movements) influenced one’s perception of the robot’s animacy and, if so, whether the strength of this influence depended on the apparent goal-directedness of the robot’s movements. We found that people only observing the robot perceived it most animated when its movements seemed most goal-directed but that people controlling the robot perceived it more animated when 1/f noise made its movements seem less goal-directed. Our perception of a moving object’s animacy thus depends on whether we interact with the object or just observe it while someone else interacts with it. This result suggests that robotics researchers should design how a robot interacts with its users, in order to elicit higher degree of animacy perception for the robot.

'Midas touch' in human-robot interaction: evidence from event-related potentials during the ultimatum game

Interpersonal touch is said to have significant effects on social interaction. We used the ultimatum game to examine whether touch from a robot could inhibit a negative feeling to the robot. We set two experimental conditions: the one was “touch condition” in which unfair proposals were offered to a participant when a robot touched his/her arm and the other was “no touch condition” in which unfair proposals were offered when the same robot did not. We compared Medial Frontal Negativity (MFN) measured by EEG, whose amplitude is correlated with feeling of unfairness, between the two conditions. Result shows that MFN amplitude was larger in the no touch condition than in the touch condition. This indicates that touch from a robot may inhibit a sense of unfairness for the robot. Our finding suggests that touch from a robot could enhance positive feeling to the robot through human-robot interaction.

Roles of the upper and lower bodies in direction discrimination of point-light walkers.

We can easily recognize human movements from very limited visual information (biological motion perception). The present study investigated how upper and lower body areas contribute to direction discrimination of a point-light (PL) walker. Observers judged the direction that the PL walker was facing. The walker performed either normal walking or hakobi, a walking style used in traditional Japanese performing arts, in which the amount of the local motion of extremities is much smaller than that in normal walking. Either the upper, lower, or full body of the PL walker was presented. Discrimination performance was found to be better for the lower body than for the upper body. We also found that discrimination performance for the lower body was affected by walking style and/or the amount of local motion signals. Additional eye movement analyses indicated that the observers initially inspected the region corresponding to the upper body, and then the gaze shifted toward the lower body. This held true even when the upper body was absent. We conjectured that the upper body subserved to localize the PL walker and the lower body to discriminate walking direction. We concluded that the upper and lower bodies play different roles in direction discrimination of a PL walker.

Healin groovy: Movement affects the appearance of the healing grid illusion

Vection alters the perception of a visual illusion. It enhances the illusory completion of the healing grid (Kanai, 2005, Best Illusion of the Year Contest, Vision Sciences Society). When we perceive our self-motion, the mode of vision is different from that of when we are stationary.

Impact of stimulus uncanniness on speeded response

In the uncanny valley phenomenon, the causes of the feeling of uncanniness as well as the impact of the uncanniness on behavioral performances still remain open. The present study investigated the behavioral effects of stimulus uncanniness, particularly with respect to speeded response. Pictures of fish were used as visual stimuli. Participants engaged in direction discrimination, spatial cueing, and dot-probe tasks. The results showed that pictures rated as strongly uncanny delayed speeded response in the discrimination of the direction of the fish. In the cueing experiment, where a fish served as a task-irrelevant and unpredictable cue for a peripheral target, we again observed that the detection of a target was slowed when the cue was an uncanny fish. Conversely, the dot-probe task suggested that uncanny fish, unlike threatening stimulus, did not capture visual spatial attention. These results suggested that stimulus uncanniness resulted in the delayed response, and importantly this modulation was not mediated by the feelings of threat.

Scintillating Lustre Induced by Radial Fins

Radial lines of Ehrenstein patterns induce illusory scintillating lustre in gray disks inserted into the central gaps (scintillating-lustre effect). We report a novel variant of this illusion by replacing the radial lines with white and black radial fins. Both white and gray disks inserted into the central gaps were perceived as scintillating, if the ratio of the black/white fin width were balanced (ie, close to 1.0). Thus, the grayness of the central disk is not a prerequisite for the scintillation. However, the scintillation was drastically reduced when the ratio was imbalanced. Furthermore, the optimal ratio depended on the color of the center disks.

Opponent colours induced by rotating discs.

We found a novel visual illusion by using a rotating disc that has some coloured sectors with black arcs. When this disc rotates, illusory colours are seen in the concentric rings that are created by the rotating arcs. The illusory colours are the opponent colours of the sectors that the corresponding arcs are in. Even though we could not differentiate the colours of the individual sectors when the disc rotated quickly the illusory colours that were the opponent colours of the sector colours could be seen. This visual illusion thus suggests that our visual system can process visual stimuli that we cannot perceive as colours.