Incompatible Flankers Research Articles

Perceptual factors affecting age-related differences in focused attention: performance and psychophysiological analyses.

In this study, the impact of two perceptual factors, feature similarity and spacing, on age-related differences in performance and psychophysiological measures were investigated within a focused attention paradigm. Young and old subjects performed an Eriksen letter identification task, in which centrally presented targets were flanked by response-compatible or response-incompatible letters. In feature similarity conditions, targets and flankers had a low or high amount of feature overlap. In spacing conditions, flankers were presented at four different lateral positions from the target. In the condition with high feature overlap and shortest target-flanker distance, old subjects showed greater interference by incompatible flankers than young subjects. Feature similarity was of little influence on age-related differences. However, spacing turned out to be of critical importance. Age-related interference effects disappeared when the target-flanker distance increased. This appears to be due to a decrease in response competition.

Attentional scanning in the selection of central targets from multi-symbol strings

Abstract Subjects responded to five-symbol strings consisting of a central target, one or two compatible or incompatible flankers, and neutral symbols in the remaining positions. Performance strongly depended on the position of compatible or incompatible flankers. With normal letters, left-side flankers had a much larger impact than right-side flankers. This left-side asymmetry of the flanker compatibility effect disappeared with strings composed of spaced letters or of tiny pictures and tended to turn into a right-side asymmetry with vertically mirrored letters. These results seem to indicate the operation of attentional scanning processes. Flankers may be scanned either automatically, due to a reading-like habit, or strategically, in attempting to localize the target.

Age-related differences in the timing of stimulus and response processes during visual selective attention: performance and psychophysiological analyses.

In this study, age-related differences in the selection of visual information were investigated. Two groups of younger and older subjects performed focused- and divided-attention (i.e., visual search) tasks. In the focused-attention task, centrally presented target letters could be flanked by compatible or incompatible noise letters. In the visual-search task, targets could be cued or uncued, and target locations could be spatially compatible or incompatible with the responding hand. P3 latency, lateralized readiness potentials, the electromyogram, and reaction times were used to detect possible age-related differences in the timing of stimulus- and response-related processes during selective processing of information. In the focused-attention task, performance of older subjects showed greater interference by incompatible flankers than did that of younger subjects because of stronger response competition caused by partial activation of the incorrect response channel by the incompatible flankers. No evidence was found of specific age-related differences in the efficiency of visual search in a divided-attention task. Furthermore, in both tasks, younger subjects showed an earlier start of response execution (in the electromyogram) relative to the onset of response preparation (lateralized readiness potential) and a higher percentage of incorrect electromyographic activity than did older subjects.

Effect of familiarity and category contrast on stimulus and response priming.

In a letter-symbol classification task, flanking incompatible symbols slowed response latencies to letter targets, whereas incompatible letter flankers did not slow the classification of symbol targets. The conditions surrounding this asymmetry in response competition were investigated in five experiments. The results showed that: (1) the asymmetry was not related to the familiarity of the symbol targets or to the prime-target interval; (2) when the classification involved familiar and unfamiliar symbols, the asymmetry remained (i.e., there was less interference associated with the unfamiliar symbol targets), but there was now significant response competition associated with both symbol categories; and (3) with a mixed-category task (i.e., letters and symbols assigned to both responses), the symbol targets continued to be less interfered with by both letter and symbol incompatible flankers. These findings were interpreted as suggesting that response competition can be influenced by both classification decision rules and cohesiveness of exemplars comprising a category.