Age‐related change of location‐based visual selectivity depending on conflict frequency

Age‐related change in cognitive control for visual selectivity was examined using a conflict adaptation effect (CAE). The CAE reflects an increased stimulus compatibility effect for low levels of conflict frequency within blocks of trials. Younger (n = 20) and elderly (n = 20) adults received an Eriksen‐type flanker task involving compatible (e.g., “44444”) or incompatible (e.g., “44644”) arrays presented to either the left or right visual field (VF). The participants identified the central digit of an array. Relative frequency of conflict (incompatible) trials varied as a function of the VF. Also manipulated was the presentation order of more‐conflict VF and less‐conflict VF conditions over trial blocks. The results showed that a location‐based CAE appeared for both age groups in the first set of trial blocks, whereas in the final set of trial blocks the location‐based CAE appeared only for the younger adults. These results suggested that cognitive flexibility related to context‐dependent cognitive control diminishes with age.     

Interhemispheric interaction in word‐ and color‐matching of Kanji color words1

Abstract: The aim of the present study was to investigate the possibility that a shift toward a within‐hemisphere advantage would emerge when two stimulus items receive, respectively, different processing (vs. when they receive similar processing). Using right‐handed participants, we briefly presented two Kanji color‐word items as either within‐field or across‐fields. Viewers had to match the two items in terms of ink color (a color‐matching task) or word meaning (a name‐matching task). Each Kanji color word was presented with the same (congruent) or different (incongruent) ink color relative to the word meaning. Our results were twofold. First, a within‐field advantage appeared in the relatively easier color‐matching task, whereas an across‐field advantage tended to occur in the relatively harder name‐matching task. Second, in the word‐matching task an across‐field advantage appeared when both Kanji color words appeared in similar processing manners (both congruent or both incongruent), whereas a within‐field advantage occurred when processing of two Kanji items differed (one congruent and one incongruent). These results suggested that a shift toward a within‐hemisphere advantage occurs when two items are processed in respectively different ways.