Abstract
Studies have demonstrated that there is a suppressive surround for any given spatial location of attentional focus in which information is inhibited (e.g., Hopf et al., 2006). Though several studies have provided psychophysical (e.g., Cutzu & Tsotsos, 2003) and neural evidence of this effect in adults (e.g., Boehler et al., 2009), whether this phenomenon is also observed earlier in development is unknown. To examine this, adults, adolescents and school-age children were tested on a two-alternative forced choice visual task, in which their accuracy in discriminating between two target letters (Ls and Ts) was measured. A spatial cue guided attention to the upcoming location of one of the target letters. Following the cue, a visual array consisting of 6 randomly oriented Ls and 6 randomly oriented Ts, arranged inon a circle grid centered on a central fixation point was displayed. The distance between the two target letters varied among six values of inter-target separation distances. Results have indicated that, as would be predicted for adults, accuracy increased linearly as the inter-target separation distance increased, suggesting that visual processing is suppressed in the immediate vicinity of an attended location. Adolescents showed a similar pattern but greater accuracy increases were observed for the larger inter-target separation distances. Further, adolescents' accuracy did not increase as gradually and linearly as with adults. Finally, school-aged children did not exhibit accuracy differences across inter-target separation distances. Thus, there were clear developmental differences in visual discrimination accuracy and the impact of surround suppression. These findings, therefore, seem to show a clear developmental trend in the efficacy of top-down processing and related attentional mechanisms, and their impact on perceptual processing and discrimination.
Meeting abstract presented at VSS 2018