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.     

Mean recovery rate: A simple measure of recovery uncontaminated by the carryover effect

Assessment of recovery is important for the investigation of stress but has been compounded by difficulties, in particular contamination by the carryover effect. In the present study, the mean recovery rate ( MRR ) was used in order to overcome this difficulty. First, the validity of the MRR was demonstrated theoretically. Second, it was demonstrated experimentally, when a comparison was made with the validity of the mean recovery per se. In the experiment, data on beat-by-beat systolic blood pressure, obtained from 18 participants before, during, and after mental arithmetic, were used as a typical sample. The implications of these results for the understanding of recovery measures are discussed.     

Contrast polarity of eyes modulates gaze‐cueing effect1

Two experiments using a modified Posner‐type visual cueing paradigm tested the prediction that detecting the darker region of the eyes of another's gaze triggers a reflexive orienting of the observer in the direction of the gaze. A target was presented in the left or right visual‐field following a gaze‐cue with positive or negative‐image polarity (Experiment 1). In Experiment 2, the polarity of the eyes was manipulated independently of the negative polarity of the face (eye‐positive or eye‐negative‐image polarity conditions). The results showed that the response to the target presented at the side the eyes gazed toward was faster than for the target presented at the other side in the positive polarity condition (Experiment 1), whereas, in the negative polarity condition, the gaze‐cuing effect was not found. In Experiment 2, in the eye‐negative condition, a reversed gaze‐cueing effect appeared, whereas in the eye‐positive polarity condition, a typical gaze‐cueing effect was obtained. These findings suggested that the reflexive orienting of the observer shifts toward the position indicated by the darker region of the other's eyes.