Working memory (WM) representations serve as templates that guide behavior, but the neural basis of these templates remains elusive. We tested the hypothesis that WM templates are maintained by biasing activity in sensoriperceptual neurons that code for features of items being held in memory. Neural activity was recorded using event-related potentials (ERPs) as participants viewed a series of faces and responded when a face matched a target face held in WM. Our prediction was that if activity in neurons coding for the features of the target is preferentially weighted during maintenance of the target, then ERP activity evoked by a nontarget probe face should be commensurate with the visual similarity between target and probe. Visual similarity was operationalized as the degree of overlap in visual features between target and probe. A face-sensitive ERP response was modulated by target-probe similarity. Amplitude was largest for probes that were similar to the target, and decreased monotonically as a function of decreasing target-probe similarity. These results indicate that neural activity is weighted in favor of visual features that comprise an actively held memory representation. As such, our findings support the notion that WM templates rely on neural populations involved in forming percepts of memory items.
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Dynamic adjustments in cognitive control are well documented in conflict tasks, wherein competition from irrelevant stimulus attributes intensifies selection demands and leads to subsequent performance benefits. The current study investigated whether mnemonic demands, in a working memory (WM) task, can drive similar online control modifications. Demand levels (high vs. low) of WM maintenance (memory load of 2 items vs. 1 item) and delay-spanning distractor interference (confusable vs. not confusable with memoranda) were manipulated using a factorial design during a WM delayed-recognition task. Performance was best subsequent to trials in which both maintenance and distractor interference demands were high, followed by trials with high demand in either of these 2 control domains, and worst following trials with low demand in both domains. These results suggest that dynamic adjustments in cognitive control are not triggered exclusively by conflict-specific contexts but are also triggered by WM demands, revealing a putative mechanism by which this system configures itself for successful task performance.
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In our database of 331 parental narratives of tantrums had by children 18–60 months old, 29% of the tantrums were followed by child-initiated affiliation with parents. Four variables increased the probability of children's post tantrum affiliation (PTA): age, prolonged screaming, physiological stress, and parent-initiated separation from the child during the tantrum. The age effect may be due to increasing post tantrum persistence of negative affect, to the emergence of shame, guilt, and embarrassment over this developmental period, and/or to increasing cognitive ability, empathic capacity, or socialization. Screaming, which may be analogous to the defensive vocalizations of nonhuman primates, increases PTA when prolonged for 6 min or more. Physiological stress (indicated by autonomic activation or respiratory distress) appears linked to prolonged screaming and may mediate its effects by increasing the child's dysphoria and need for consolation. Separation (parents' departure from the scene of the tantrum or their imposition of a time out) also appears linked to prolonged screaming and may reflect parents' response to an aversive auditory stimulus. There was no evidence that PTA was associated with the presence or degree of physically expressed anger in the tantrum. PTA may be associated with distress during the tantrum. The post conflict reconciliation which occurs in several domains of human social life may be first experienced by children in the aftermath of their tantrums. Aggr. Behav. 23:329–341, 1997. © 1997 Wiley-Liss, Inc.
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