The human likeness dimension of the “uncanny valley hypothesis”: behavioral and functional MRI findings

Abstract

The uncanny valley hypothesis (Mori, 1970) predicts differential experience of negative and positive affect as a function of human likeness. Affective experience of humanlike robots and computer-generated characters (avatars) dominates “uncanny” research, but findings are inconsistent. Importantly, it is unknown how objects are actually perceived along the hypothesis’ dimension of human likeness (DOH), defined in terms of human physical similarity. To examine whether the DOH can also be defined in terms of effects of categorical perception (CP), stimuli from morph continua with controlled differences in physical human likeness between avatar and human faces as endpoints were presented. Two behavioral studies found a sharp category boundary along the DOH and enhanced visual discrimination (i.e., CP) of fine-grained differences between pairs of faces at the category boundary. Discrimination was better for face pairs presenting category change in the human-to-avatar than avatar-to-human direction along the DOH. To investigate brain representation of physical change and category change along the DOH, an event-related functional magnetic resonance imaging study used the same stimuli in a pair-repetition priming paradigm. Bilateral mid-fusiform areas and a different right mid-fusiform area were sensitive to physical change within the human and avatar categories, respectively, whereas entirely different regions were sensitive to the human-to-avatar (caudate head, putamen, thalamus, red nucleus) and avatar-to-human (hippocampus, amygdala, mid-insula) direction of category change. These findings show that Mori’s DOH definition does not reflect subjective perception of human likeness and suggest that future “uncanny” studies consider CP and the DOH’s category structure in guiding experience of non-human objects.

Now you feel it, now you don’t

“…Study 1). This observation suggests that both types of evaluations may be linked by a common affective core, supporting definitions of eeriness which emphasize feelings of fear and anxiety (Cheetham, Suter, & Jäncke, 2011). The exact relation between feelings of eeriness and safety concerns, however, deserves further investigation.…”

Aesthetic of Prosthetic Devices: From Medical Equipment to a Work of Design

“…lightweight, movement in the ankle), but they also require visual appeal in the devices to fulfil their emotional needs and connect the look of the related product to their body image. Unlike the extended work to date on prosthetics which has largely focused on the technical improvement of the devices (Cheetham, Suter, & Jäncke, 2011;Hahl, Taya, & Saito, 2000;Klute, Kallfelz, & Czerniecki, 2001;Mak, Zhang, & Boone, 2001), the field of research into aesthetic of prostheses is new, as little interest in this sector of prosthetic design has been recorded.…”

Perceptual and Category Processing of the Uncanny Valley Hypothesis' Dimension of Human Likeness: Some Methodological Issues

“…One of a number of reasons for this is that human likeness is not perceived as the hypothesis assumes. While the DHL can be defined following Mori's description as a smooth linear change in the degree of physical humanlike similarity, subjective perception of objects along the DHL can be understood in terms of the psychological effects of categorical perception (CP) 7 . Further behavioral and neuroimaging investigations of category processing and CP along the DHL and of the potential influence of the dimension's underlying category structure on affective experience are needed.…”