Individual differences in skilled reaching for food related to increased number of gestures: Evidence for goal and habit learning of skilled reaching.

Skilled reaching in rodents and primate is motorically similar, but success in reaching by rodents is distinctively variable. The source of this variability has not been examined previously. Long–Evans rats were videotaped as they reached for food in 2 different reaching tasks, and endpoint measures of performance were examined in relation to variables previously associated with individual differences, including testing procedures, rehabilitation, movement ability, general locomotor activity, and cortical anatomy. There were individual differences in performance, but these were not related to the dependent measures related to training, movement ability, locomotor activity, or anatomy (e.g., brain with cortical thickness, acetylcholinesterase and neuron density, pyramidal tract size). Success was negatively related to numbers of gestures (non–weight-bearing movements of the reaching limb) used on a reach, however. The results are discussed in relation to the idea that individual differences in response strategy bias some rats to use a more successful goal strategy and others to use a less successful habit strategy for skilled reaching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reading aloud: Evidence for contextual control over lexical activation.

Can readers exert control (albeit unconsciously) over activation at particular loci in the reading system? The authors addressed this issue in 4 experiments in which participants read target words aloud and the factors of prime–target relation (semantic, repetition), context (related, unrelated), stimulus quality (bright, dim), and relatedness proportion (RP; high, low) were manipulated. In the high RP condition (RP = .5), an interaction between semantic context and stimulus quality was observed in which low stimulus quality slowed unrelated targets more than related ones, replicating previous work. In contrast, the low RP condition (RP = .25) yielded additive effects of semantic context and stimulus quality. However, when low RP was examined within the context of repetition priming, context and stimulus quality once again interacted. These results are discussed in the context of a widely endorsed framework with the addition of the central assumption that there is control over feedback between various levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A survey of studies contrasting the quality of group performance and individual performance, 1920-1957.

Research contrasting the quality of group performance with individual performance in each of the following general topic areas has been examined in this paper: judgment, learning, social facilitation, problem solving, memory, size of group, problem solving in more realistic situations, and productivity. Recent theoretical and methodological considerations as well as discussions of group types are included. Research weakness and theoretical problems are discussed. 74 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task Switching in a Hierarchical Task Structure: Evidence for the Fragility of the Task Repetition Benefit.

This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms. In Experiments 2-5, adjacent task elements were grouped temporally and/or spatially (forming an ensemble) to create a hierarchical task organization. Results indicate that the effect of switching at the ensemble level dominated the effect of switching at the element level. Experiments 6 and 7, using an ensemble of 3 task elements, revealed that the element-level switch cost was virtually absent between ensembles but was large within an ensemble. The authors conclude that the element-level task repetition benefit is fragile and can be eliminated in a hierarchical task organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual word recognition: Evidence for global and local control over semantic feedback.

Two lexical decision experiments examined the joint effects of stimulus quality, semantic context, and cue-target associative strength when all factors were intermixed in a block of trials. Both experiments found a three-way interaction. Semantic context and stimulus quality interacted when associative strength between cue-target pairs was strong, and the interaction was eliminated when the strength was weak. These results support a role for a local mechanism that relies on trial specific information, in addition to a mechanism that makes use of global information available across a block of trials. The absence of an interaction between the joint effects of semantic context and stimulus quality is attributed to blocking the feedback from the semantic system to the orthographic system, functionally separating the orthographic and semantic modules. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Generalized signaling for control: Evidence from postconflict and posterror performance adjustments.

Goal-directed behavior requires cognitive control to effect online adjustments in response to ongoing processing demands. How signaling for these adjustments occurs has been a question of much interest. A basic question regarding the architecture of the cognitive control system is whether such signaling for control is specific to task context or generalizes across contexts. In this study, the authors explored this issue using a stimulus–response compatibility paradigm. They examined trial-to-trial adjustments, specifically, the findings that incompatible trials elicit improved performance on subsequent incompatible trials and that responses are slower after errors. The critical question was, Do such control effects—typically observed within a single task context—occur across task contexts? The paradigm involved 2 orthogonal, stimulus–response sets: Stimuli in the horizontal direction mapped only to responses in the horizontal direction, and likewise for the vertical direction. Cues indicated that either compatible (same direction as stimulus) or incompatible (opposite to stimulus) responses were required. The results showed that trial-to-trial adjustments exist for both direction-repeat and direction-switch trials, demonstrating that signaling for control adjustments can extend beyond the task context within which they arise. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociating consciousness from inhibitory control: Evidence for unconsciously triggered response inhibition in the stop-signal task.

Theories about the functional relevance of consciousness commonly posit that higher order cognitive control functions, such as response inhibition, require consciousness. To test this assertion, the authors designed a masked stop-signal paradigm to examine whether response inhibition could be triggered and initiated by masked stop signals, which inform participants to stop an action they have begun. In 2 experiments, masked stop signals were observed to occasionally result in full response inhibition as well as to yield a slow down in the speed of responses that were not inhibited. The magnitude of this subliminally triggered response time slowing effect correlated with the efficiency measure (stop signal reaction time) of response inhibition across participants. Thus, response inhibition can be triggered unconsciously—more so in individuals who are good inhibitors and under conditions that are associated with efficient response inhibition. These results indicate that in contradiction to common theorizing, inhibitory control processes can operate outside awareness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contextual effects on reading aloud: Evidence for pathway control.

Recent evidence suggests that the processes responsible for generating a phonological code from print are flexible in skilled readers. An important goal, therefore, is to identify the conditions that lead to changes in how a phonological code is computed. Five experiments are reported that examine whether phonological processes change as predicted by the pathway control hypothesis when reading aloud words and nonwords. Changes in reading processes were assessed by measuring the effect of predictable switches between stimulus categories across trials. The results of the present experiments are argued to be consistent with the pathway control hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hand path priming in manual obstacle avoidance: Evidence for abstract spatiotemporal forms in human motor control.

Previous research suggests that motor equivalence is achieved through reliance on effector-independent spatiotemporal forms. Here the authors report a series of experiments investigating the role of such forms in the production of movement sequences. Participants were asked to complete series of arm movements in time with a metronome and, on some trials, with an obstacle between 1 or more of the target pairs. In moves following an obstacle, participants only gradually reduced the peak heights of their manual jumping movements. This hand path priming effect, scaled with obstacle height, was preserved when participants cleared the obstacle with 1 hand and continued with the other, and it was modulated by future task demands. The results are consistent with the hypothesis that the control of movement sequences relies on abstract spatiotemporal forms. The data also support the view that motor programming is largely achieved by changing just those features that distinguish the next movement to be made from the movement that was just made. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Personality change over 40 years of adulthood: Hierarchical linear modeling analyses of two longitudinal samples.

Normative personality change over 40 years was shown in 2 longitudinal cohorts with hierarchical linear modeling of California Psychological Inventory data obtained at multiple times between ages 21-75. Although themes of change and the paucity of differences attributable to gender and cohort largely supported findings of multiethnic cross-sectional samples, the authors also found much quadratic change and much individual variability. The form of quadratic change supported predictions about the influence of period of life and social climate as factors in change over the adult years: Scores on Dominance and Independence peaked in the middle age of both cohorts, and scores on Responsibility were lowest during peak years of the culture of individualism. The idea that personality change is most pronounced before age 30 and then reaches a plateau received no support. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural basis of individual differences in impulsivity: Contributions of corticolimbic circuits for behavioral arousal and control.

The objective of the current study was to analyze the neural correlates of behavioral arousal and inhibitory control as they relate to individual differences in impulsivity via well-established functional MRI amygdala reactivity and prefrontal inhibitory control paradigms in healthy adult subjects. Impulsivity correlated positively with activity of the bilateral ventral amygdala, parahippocampal gyrus, dorsal anterior cingulate gyrus (BA 32), and bilateral caudate. Conversely, impulsivity correlated negatively with activity of the dorsal amygdala and ventral prefrontal cortex (BA 47). Together, these findings suggest that dispositional impulsivity is influenced by the functional interplay of corticolimbic behavioral arousal and control circuits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experience-based mitigation of age-related performance declines: Evidence from air traffic control.

[Correction Notice: An erratum for this article was reported in Vol 15(2) of Journal of Experimental Psychology: Applied (see record 2009-09189-003). In the article, the URL published for the supplemental material was incorrect. The correct URL is http://dx.doi.org/10.1037/a0014947.supp] Previous research has found age-related deficits in a variety of cognitive processes. However, some studies have demonstrated age-related sparing on tasks where individuals have substantial experience, often attained over many decades. Here, the authors examined whether decades of experience in a fast-paced demanding profession, air traffic control (ATC), would enable older controllers to perform at high levels of proficiency. The authors also investigated whether older controllers would show diminished age-related decrements on domain-relevant cognitive abilities. Both young and old controllers and noncontrollers performed a battery of cognitive and ATC tasks. Results indicate that although high levels of experience can reduce the magnitude of age-related decline on the component processes that underlie complex task performance, this sparing is limited in scope. More important, however, the authors observed experience-based sparing on simulated ATC tasks, with the sparing being most evident on the more complex air traffic control tasks. These results suggest that given substantial experience, older adults may be quite capable of performing at high levels of proficiency on fast-paced demanding real-world tasks. The implications of these findings for global skilled labor shortages are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contraints on information processing under alcohol in the context of response execution and response suppression.

This study tested the degree that alcohol restricts information processing on tasks requiring response execution and response suppression. A dual task required 12 participants to respond to 2 task stimuli (Tasks 1 and 2) presented in close succession. The task was performed before and after receiving 3 alcohol doses (placebo, 0.45 g/kg, and 0.65 g/kg) administered on separate days in a counterbalanced order. Alcohol increased task interference, as evidenced by increased time to respond to Task 2. Impairment was comparable regardless of whether Task 1 required a response to be executed or suppressed. The evidence supports a resource limitation account that argues that alcohol reduces capacity to process information required for execution and suppression of responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The menstrual cycle and typing skill: An ecologically-valid test of the "raging hormones" hypothesis.

Tested the "raging hormones" hypothesis, which states that the performance of women is periodically impaired during the perimenstruum. The typing skill of 9 female professional typists (aged 24–40 yrs) was evaluated at work with the use of typing tests administered at intervals throughout the menstrual cycle. There was no variation in typing performance as a function of the menstrual cycle for errors or rate of typing. Moreover, no variation of self-reported mood with the menstrual cycle was observed. Findings refute the view that work performance, at least for a skilled perceptual-motor task, is impaired at any phase of the menstrual cycle. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On attentional control as a source of residual shift costs: Evidence from two-component task shifts.

It is widely assumed that supervisory or attentional control plays a role only in the preparatory reconfiguration of the mental system in task shifting. The well-known fact that residual shift costs are still present even after extensive preparation is usually attributed to passive mechanisms such as cross talk. The authors question this view and suggest that attentional control is also responsible for residual shift costs. The authors hypothesize that, under shift conditions, tasks are executed in a controlled mode to guarantee reliable performance. Consequently, the control of 2 task components should require more resources than the control of only 1. A series of 4 experiments with 2-component tasks was conducted to test this hypothesis. As expected, more residual shift costs were observed when 2 components rather than 1 varied across trials. Interference effects and sequential effects could not account for these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A shift in task routines during the learning of a motor skill: Group-averaged data may mask critical phases in the individuals' acquisition of skilled performance.

The authors describe a transient phase during training on a movement sequence wherein, after an initial improvement in speed and decrease in variability, individual participants' performance showed a significant increase in variability without change in mean performance speed. Subsequent to this phase, as practice continued, variability again decreased, performance significantly exceeded the gains predicted by extrapolation of the initial learning curve, the type of errors committed changed, and performance became more coherent. The transient phase of increased variability may reflect a mixture of 2 (or more) performance routines before the more effective one is set and mastered, presumably the setting up of a sequence-specific representation. Both group and individual analyses indicated a departure from the single process (e.g., power-law) model of learning. However, although similar phases appeared in the mean group data, there was little correspondence to individual participants' time courses, and the individuals' gains in the second low-variability phase were masked. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feelings change: Accounting for individual differences in the temporal dynamics of affect.

People display a remarkable variability in the patterns and trajectories with which their feelings change over time. In this article, we present a theoretical account for the dynamics of affect (DynAffect) that identifies the major processes underlying individual differences in the temporal dynamics of affective experiences. It is hypothesized that individuals are characterized by an affective home base, a baseline attractor state around which affect fluctuates. These fluctuations vary as the result of internal or external processes to which an individual is more or less sensitive and are regulated and tied back to the home base by the attractor strength. Individual differences in these 3 processes—affective home base, variability, and attractor strength—are proposed to underlie individual differences in affect dynamics. The DynAffect account is empirically evaluated by means of a diffusion modeling approach in 2 extensive experience-sampling studies on people's core affective experiences. The findings show that the model is capable of adequately capturing the observed dynamics in core affect across both large (Study 1) and shorter time scales (Study 2) and illuminate how the key processes are related to personality and emotion dispositions. Implications for the understanding of affect dynamics and affective dysfunctioning in psychopathology are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hierarchical control of cognitive processes: Switching tasks in sequences.

[Correction Notice: An erratum for this article was reported in Vol 136(2) of Journal of Experimental Psychology: General (see record 2007-06470-005). Two task transitions were classified incorrectly in Table 7 (p. 634). Two task transitions were classified incorrectly in Table 7 (p. 634). The task transition at Serial Position 1 for sequence switches of the AABB sequence should be TR instead of TS. The task transition at Serial Position 1 for sequence switches of the ABBA sequence should be TS instead of TR. Two sections of text in the Results and Discussion section of Experiment 4 were affected by the misclassifications. The corrected text is provided for the Error rate analysis section (pp. 634-635) and the RT analysis section (p.635). These corrections do not alter any of the conclusions drawn from the original text.] Hierarchical control of cognitive processes was studied by examining the relationship between sequence- and task-level processing in the performance of explicit, memorized task sequences. In 4 experiments, switch costs in task-switching performance were perturbed by sequence initiation times that varied with sequence complexity, preparation time, and type of sequence transition (repetition or switch). Hierarchical control was inferred from these sequence initiation time effects and the recurrent finding of no switch cost at the first serial position across sequences, the point at which sequence-level processes are likely active in maintaining or instantiating a hierarchical control structure in working memory. These findings resonate with past research on motor programs and serial memory and provide new insights into the concepts of task set and control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of individual versus aggregate social comparison and the presence of others on self-evaluations.

In 5 studies, the authors investigated the effects of comparison with an individual versus comparison with the statistical average on self-evaluations of performance and ability. In Studies 1 and 2, participants took a test of lie detection ability and were provided with the average score and the score of an individual coactor. Both types of feedback significantly affected self-evaluations of performance, but only comparison with the coactor significantly affected self-evaluations of ability. Studies 3 and 4 demonstrated that the presence of a coactor moderated the effect of aggregate social comparison on self-evaluations of ability. The results provide preliminary support for the contention that minimizing the impact of comparison with the average is a self-serving strategy that is facilitated by the presence of others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motor preparation and the effects of practice: Evidence from startle.

To examine sequential movement preparation, participants practiced unimanual movements that differed in amplitude and number of elements for 4 days in either a simple (Experiment 1) or choice (Experiment 2) reaction time (RT) paradigm. On Day 1 and 4, a startling stimulus was used to probe the preparation process. For simple RT, we found increased premotor RT for the two component movement during control trials on Day 1, which was minimized with practice. During startle trials, all movements were triggered at a short latency with similar consistency to control trials, suggesting full advance preparation of all movements. For choice RT, we also found increased premotor RT for control trials for the two component movement. As advance preparation could not occur, the startling stimulus did not trigger any of the movements. We hypothesized that complexity may relate to the neural commands needed to produce the movement, rather than a sequencing requirement. (PsycINFO Database Record (c) 2011 APA, all rights reserved)