Abstract
Natural images have lawful statistical properties that the adult visual system is sensitive to, both in terms of behavior and neural responses to natural images. The developmental trajectory of sensitivity to natural image statistics remains unclear, however. In behavioral tasks, children appear to slowly acquire adult-like sensitivity to natural image statistics during middle childhood (Ellemberg et al., 2012), but in other tasks, infants exhibit some sensitivity to deviations of natural image structure (Balas & Woods, 2014). Here, we used event-related potentials (ERPs) to examine how sensitivity to natural image statistics changes during childhood at distinct stages of visual processing (the P1 and N1 components).
We recruited 48 participants (5-7 year-olds, N=16; 8-10 year-olds, N=16, Adults, N=16) , who viewed natural texture images with either positive/negative contrast, and natural/synthetic texture appearance (Portilla & Simoncelli, 2000). We hypothesized that children may only acquire sensitivity to these deviations from natural texture appearance late in middle childhood, consistent with previous results suggesting that texture and material processing follow a local-to-global developmental trajectory (Balas et al., 2019).
We measured the P1/N1 mean amplitude and latency over occipital sensors in all participants. We observed significant interactions between contrast and age group for P1 latency, and between texture statistics and age group for N1 amplitude. Both effects reflect greater sensitivity to natural image appearance in children compared to adults. In particular, we observed no effects of image contrast in adults, while young children exhibited a latency effect at the P100. Sensitivity to contrast negation was also evident in young children at a late component (~350ms) that in older children and adults was only sensitive to texture statistics. We discuss these results in terms of changing patterns of invariant texture processing during middle childhood and ongoing refinement of the representations supporting natural image perception.