Developmental differences in visual backward masking.
2 experiments were conducted to examine developmental differences in visual recognition masking when verbal encoding and response demands are minimized. Precautions were taken in the experiments to ensure the implication of the central visual system in the backward-masking component of each experiment. Sampling was conducted across the kindergarten, third-grade, sixth-grade, and college levels. In the first experiment, no-mask target recognition was set at 100% correct. The results indicated systematic grade differences in backward masking such that older children and adults showed more rapid recognition improvement across stimulus onset asynchronies (SOAs) than did young subjects (i.e., a grade x SOA interaction). Although this finding could be interpreted to suggest developmental differences in the rate of visual information processing, such an interpretation would be inappropriate. The problem is that the masking functions for all grade levels reach asymptote at 100% correct (i.e., a ceiling effect). Thus, the grade X SOA interaction could have been produced for reasons other than rate-of-processing differences (e.g., developmental differences in the quality of stimulus reception). Thus, experiment 2 was designed to assess this possibility by evaluating developmental differences in visual backward masking when no-mask target recognition was set at the 75% level for the grades sampled. The grade x SOA interaction observed in experiment 1 was not observed in experiment 2. The results from the studies indicate that, when the ceiling effects in no-mask target recognition are removed, the visual information processing rates for children and adults can be considered equivalent.