Electrophysiological evidence for the oblique effect in human infants

Visually-evoked potentials (VEPs) were recorded from infants between the ages of 2 and 11 months in response to 2.5 c/deg main axis and oblique square wave gratings. The oblique effect first appears at 3 months of age; some infants showed smaller VEP amplitude and/or longer VEP latency for obliquely oriented gratings. Regarding the age of onset of the oblique effect, VEP data from this study agree with the results obtained with preferential looking (PL) studies which have directly paired vertical and oblique gratings, but the current study found that fewer infants show an oblique effect by VEP than by PL.