The effects of stimulus movement and attention on peripheral stimulus localization by 8- to 26-week-old infants

This study examined the effect of stimulus movement on localization probabi lity and latency during attention and inattention. Forty infants, 10 each a t 8, 14, 20, and 26 weeks of age were presented with a central stimulus. Th en, a peripheral stimulus was presented (static or dynamic checkerboard). S timulus movement did not affect localization probability. Infants localized the dynamic peripheral stimulus more quickly than the static peripheral st imulus when there was no focal stimulus. Focal stimulus attention attenuate d this difference in localization latency between static and dynamic stimul i. Signal detection analysis showed that sensitivity to the peripheral stim ulus increased over this age range along with a decrease in the bias agains t responding. The effects of attention were on response bias rather than st imulus sensitivity. These results imply attention affected the localization response to the peripheral stimulus but did not affect the sensitivity of the sensory and perceptual pathways to peripheral stimuli.