Task-irrelevant visual perceptual learning in children and adults
Task-irrelevant visual perceptual learning (VPL) was examined in a group of elementary school age children (7 – 10 years old, n = 20 subjects) and a group of young adults (18 – 31 years old, n = 20 subjects). The experiment consisted of several sessions conducted on separate days. In the first session subjects’ thresholds for coherent motion detection were measured. In the second session subjects completed a pretest for discrimination performance of different coherent motion directions. From the third to the fourteenth session subjects performed a rapid serial visual presentation (RSVP) task at screen center while coherent motion in different directions was exposed as task-irrelevant in the visual periphery. Prior to the experiment each subject was randomly assigned to two different exposure conditions (n = 10 subjects for each age group for each exposure condition). There was a threshold exposure condition in which coherent motion was exposed at the individual threshold for coherent motion detection. There was also a suprathreshold exposure condition in which coherent motion was exposed at 4.0 x individual threshold for coherent motion detection. In each trial of the RSVP one coherent motion direction, termed the “task-irrelevant learning direction” was exclusively paired with RSVP targets, while other coherent motion directions were randomly paired with RSVP distractors (“untrained directions”). Finally, in the fifteenth session subjects completed a posttest in motion direction discrimination exactly as in the pretest. The results show that subjects in both age groups improved significantly on the RSVP over the course of the exposure sessions. In the threshold exposure condition subjects in each age group significantly improved discrimination performance for the task-irrelevant learning direction from pretest to posttest. In the suprathreshold exposure condition children significantly improved discrimination performance for the task-irrelevant learning direction from pretest to posttest, while young adults significantly decreased discrimination performance. Furthermore, subjects also completed the Useful Field of View (UFOV) subtests for processing speed, divided attention and selective attention. The discrimination performance increase in the suprathreshold exposure condition in children was significantly correlated with the selective attention ability, such that children with greater discrimination performance increase from pretest to posttest also tended to show greater selective attention ability. No such association was observed either for young adults or for any other UFOV subtest.