Effects of image blur on visual perception and affective response

Obscure visual environments impair visual perception and result in the worse performances in object detection, identification, and recognition. Blurred images might also induce negative affective responses to the visual environment such as fear or uncanniness. However, the effect of image blur on the affective responses is still open. The present study investigated the effects of image blur on the object detection and the feeling of uncanniness. In a psychological experiment, we presented pictures of natural images depicting a person, an animal, or an object and asked participants to indicate whether the picture depicted a face or an animal and to rate how strongly they felt the picture was uncanny. The images were blurred by the lowpass filter of various cutoff frequencies. We found that the more blurry images, namely images filtered by the lower cutoff frequencies, were more difficult in face/animal detection as well as they were rated as more uncanny. However, the effective cutoff frequencies in the modulations on the uncanniness rating and face/animal detectability did not overlap; the uncanniness and detectability did not show clear correlation. These results clearly demonstrated that the image blur elicits the negative affective responses. Furthermore, although the image blur influences both visual perception and affective response in a similar fashion, the feelings of uncanniness and face/animal detectability were not related directly from each other.