Abstract
Aim: Mass educational/entertainment media is currently directed at infants (e.g., "Baby Einstein"), yet the consequences on perceptual development are unknown. Here, we asked whether exposing 3-month-olds to Chromatic (Chrom, red/green) and Luminance (Lum, dark/light) patterns affects their sensitivity to these stimuli.
Methods: The stimuli were Lum and Chrom gratings (0.27 cpd; 4 Hz). The experiment took place over 3 days: Day 1: Pre-exposure testing, Day 2: Video-Exposure (10-minute video; exposure confirmed with fixation monitoring), Day 3: Post-exposure testing. Infants were randomly assigned to groups: Lum-Exposed (n=12), Chrom-Exposed (n=12), and No Exposure (listened to music, n=11) for a "control" measure of first/second test performance change. On Days 1 and 3, contrast sensitivity was measured using FPL and interleaved Lum/Chrom staircases. Post/Pre-Exposure log Sensitivity Ratios (SR) were calculated, with SR>0 reflecting improved sensitivity between first/second test. As a "boredom" control, we measured looking times for Lum vs. Chrom stimuli presented side-by-side. Post/Pre-Exposure log Preference Ratios (PR) were calculated, with PR>0 reflecting increased looking to the exposed stimulus.
Results: Exposure to a Lum video resulted in changes to SRs that differed for stimulus type, as evidenced by a significant interaction (p=0.05) between group (Lum-exposed vs. Controls) x stimulus type (Lum vs. Chrom). This was driven by an improvement in Chrom and a decrement in Lum sensitivity. This effect is unlikely to be due to boredom with the Lum stimuli, since PRs for Lum vs. Chrom stimuli did not change as a result of exposure. No main effects or interaction were seen in infants exposed to the Chrom video.
Conclusions: The selective performance decrement in 3-month-olds may be consistent with perceptual deterioration seen in adults, following practice, not explained by boredom or fatigue (Mednick et al, 2005). These results join the trove of controversial evidence pointing to the ineffectual, even negative, effects of television during infancy.
Meeting abstract presented at VSS 2012