Abstract
Human ignore changes due to environment to perceive a constant object. For example, previous studies showed that adults ignored changes in shadows implicitly. However, the development of this ability is still an open question. Recently, Yang et al. (2015) found that 7-to-8-month-old infants could detect changes in materials of objects. In contrast, 3-to-4-month-old infants could detect changes in light-field caused by illumination changes better than adults and 7-to-8-month-olds. These results suggested that infants in pre-constancy have an ability to discriminate local changes that adults ignore. In our study, we investigated whether infants aged 3-to-8-months could detect changes in self-shadow of objects by using a change-detection paradigm. We presented changing image and non-changing image sequences side by side. Each sequence consisted of two images, and all images were flashed in rapid alternation with an interstimulus interval (ISI). We hypothesized that infants would prefer to the changing image sequence if they could detect changes of image property. We set two conditions for different changing image sequence; the shadow-change condition and the shape change condition. In the self-shadow change condition, an image pair consisted of images rendered from a same object with different illumination direction. In the shape change condition, an image pair consisted of images rendered from two objects with different three-dimensional structure. In the non-changing image sequence, the same image of object was presented repeatedly. Results revealed that 7-to-8-month-olds looked longer to the changing image sequence than non-changing image sequence only in the shape change condition. In contrast, 3-to-4-month-olds show the preference for the changing image sequence only in the shadow change condition. These results suggest that 7-to-8-month-old infants could not detect the changes in object's self-shadow but can detect the changes in three-dimensional structure, whereas 3-to-4-month-olds could detect local changes in images that are not salient for 7-to-8-month-olds.
Meeting abstract presented at VSS 2018