Influence of appearance and motion interaction on emotional state attribution to objects: The example of hugging shimeji mushrooms

Feeling that a non-human object has emotions (hereinafter referred to as emotional state attribution) is generally known as animacy perception. Previous studies have considered appearance and motion separately as factors that evoke emotional state attribution. Then, if both the degree of human likeness in shape and the presence or absence of motion are considered simultaneously, is there a possibility of strong emotional state attribution even for objects that are not human-like in terms of shape? In this study, we experimentally investigated the influence of human likeness in shape and movements evoking social relations on emotional state attribution, including their interaction, using three types of objects (human figure, shimeji mushroom, and match) that were assumed to differ from humans in terms of shape. We conducted three experiments. In Experiment 1, although the human figure was rated as more human-like than the shimeji mushroom in terms of shape, emotions were attributed more strongly to the shimeji mushroom than to the human figure when accompanied by movements that evoked social relationships. In Experiment 2, a follow-up to Experiment 1 was conducted by eliminating the influence of three-dimensionality, and similar results to Experiment 1 were obtained. In Experiment 3, the influence of face parts was examined, and emotions were attributed more strongly when motion was given to an object without face parts. The results suggest that people may attribute emotions more strongly to faceless objects that resemble humans only to a certain extent in shape when they show movements that evoke social relations.