Implicit task sets in task switching?

In 2 experiments, the authors compare stimulus-based versus task-rule-based task performance. Participants practiced 8 stimulus-response mappings either with or without knowledge about 2 underlying task sets. After practice, 2 transfer blocks with 8 new stimuli were presented. Results show that rule knowledge leads to significant switch and transfer costs, whereas without rule knowledge neither switch nor transfer costs occur. However, significant Task Type × Response Type interactions occurred in both conditions. In a second experiment including only the no rule condition, half of the stimulus-response mappings in the transfer blocks were incongruent to the underlying task rule. Slower response times for these incongruent stimuli as compared with congruent stimuli and the absence of switch costs suggest that participants acquired (presumably implicit) knowledge about 4 different stimulus-response categories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Configural response learning: The acquisition of a nonpredictive motor skill.

This study examined the representational nature of configural response learning using a task that required simultaneous keypresses with 2 or 3 fingers, similar to the production of chords on the piano. If the benefits of learning are related to the retrieval of individual stimulus-response mappings, performance should depend on the frequencies of the individual responses forming each chord. Alternatively, learning may involve the encoding of configural information concerning the relationship between the chord elements. In Experiment 1, training was restricted to a subset of the 120 possible 3-element chords. Probe blocks included the practiced chords, chords composed of novel configurations of practiced elements (reconfigured), and chords that contained a new element (new). Practiced chords were performed faster than reconfigured chords, indicating learning involves the encoding of configural information. Experiment 2 showed that learning was not restricted to configurations within each hand. Experiments 3 and 4 demonstrated that learning was largely response based. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stimulus-response compatibility with pure and mixed mappings in a flight task environment.

The present study examined the stimulus-response compatibility (SRC) effect in a simulated flight environment. Experiments 1 and 2 tested the effect with pure and mixed mappings in flight tasks by using attitude displays with inside-out and outside-in formats, whereas Experiments 3 and 4 used a simplified display and tasks. The SRC effect was obtained with mixed mappings when responses were turns of a flight yoke (Experiments 1-3). In contrast, the SRC effect was absent with mixed mappings when they were buttonpresses (Experiment 4). Analyses of sequential effects suggest that the reduction in Experiments 1-3 can be attributed to reduction in the frequency of trials for which the congruent mapping repeats, but the elimination in Experiment 4 cannot be. Implications of the findings are discussed in the context of aviation cockpit design. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contextual interference effects in sequence learning for young and older adults.

Practice of different tasks in a random order induces better retention than practicing them in a blocked order, a phenomenon known as the contextual interference (CI) effect. Our purpose was to investigate whether the CI effect exists in sequence learning, such that practicing different sequences in a random order will result in better learning of sequences than practicing them in blocks, and whether this effect is affected by aging. Subjects practiced a serial reaction time task where a set of three 4-element sequences were arranged in blocks or in a random order on 2 successive days. Subjects were divided into 4 groups based on a 2-GROUP (young or old) by 2-ORDER (random or blocked practice) between-subject design. Three days after practice (Day 5), subjects were tested with practiced and novel sequences to evaluate sequence-specific learning. The results replicate the CI effect in sequence learning in both young and older adults. Older adults retained sequences better when trained in a random condition than in a blocked condition, although the random condition incurs greater task switching costs in older adults during practice. Our study underscores the distinction between age-related effects on learning vs. performance, and offers practical implications for enhancing skill learning in older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Remembrance of sounds past: Memory and psychophysical scaling.

What is the role of long-term memories of previous stimulus-response mappings, and of previous sensory and perceptual experiences generally, in psychophysical scaling judgments? In each of 4 experiments, subjects made judgments of the loudness of sounds on 3 successive days. Stimulus intensities were drawn randomly from the same set on Days 1 and 3 but from a different set on Day 2. Four different types of psychophysical scaling judgments were studied. The first two methods required completely relative judgment, the last two completely absolute judgment. Data from all methods reveal profound effects of stimulus-response mappings experienced on previous days and immediately previous stimuli and responses on responses to current stimuli. Responses were typically a compromise between absolute and relative judgment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Localizing sequential effects in serial choice reaction time with the information reduction procedure.

Patterns of sequential effects in serial 2-choice reaction time (RT) tasks have been explained by 2 processing mechanisms, automatic facilitation and subjective expectancy, depending on the response-to-stimulus interval (RSI) and stimulus-response compatibility. Both mechanisms were localized in stimulus- or response-related processing stages with 4-stimulus 2-response experiments. Stimuli were presented on the corners of a square and keys were left-right or up-down. Subjective expectancy, appearing at long RSI, was systematically response related. Automatic facilitation, appearing with short RSI, shifted toward stimulus-related processes with noncompatible mappings. The results support the idea that automatic facilitation is related to structural bottom-up processes and is mainly located in stages that gain most from a facilitatory effect, whereas subjective expectancy needs a minimum time and therefore appears in late, response-related stages. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous dual-task performance reveals parallel response selection after practice.

E. H. Schumacher, T. L. Seymour, J. A Glass, D. E. Kieras, and D. E. Meyer (2001) reported that dual-task costs are minimal when participants are practiced and give the 2 tasks equal emphasis. The present research examined whether such findings are compatible with the operation of an efficient response selection bottleneck. Participants trained until they were able to perform both tasks simultaneously without interference. Novel stimulus pairs produced no reaction time costs, arguing against the development of compound stimulus-response associations (Experiment 1). Manipulating the relative onsets (Experiments 2 and 4) and durations (Experiments 3 and 4) of response selection processes did not lead to dual-task costs. The results indicate that the 2 tasks did not share a bottleneck after practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age Equivalence in Switch Costs for Prosaccade and Antisaccade Tasks.

This study examined age differences in task switching using prosaccade and antisaccade tasks. Significant specific and general switch costs were found for both young and old adults, suggesting the existence of 2 types of processes: those responsible for activation of the currently relevant task set and deactivation of the previously relevant task set and those responsible for maintaining more than 1 task active in working memory. Contrary to the findings of previous research, which used manual response tasks with arbitrary stimulus-response mappings to study task-switching performance, no age-related deficits in either type of switch costs were found. These data suggest age-related sparing of task-switching processes in situations in which memory load is low and stimulus-response mappings are well learned. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Polarity correspondence: A general principle for performance of speeded binary classification tasks.

Differences in performance with various stimulus-response mappings are among the most prevalent findings for binary choice reaction tasks. The authors show that perceptual or conceptual similarity is not necessary to obtain mapping effects; a type of structural similarity is sufficient. Specifically, stimulus and response alternatives are coded as positive and negative polarity along several dimensions, and polarity correspondence is sufficient to produce mapping effects. The authors make the case for this polarity correspondence principle using the literature on word-picture verification and then provide evidence that polarity correspondence is a determinant of mapping effects in orthogonal stimulus-response compatibility, numerical judgment, and implicit association tasks. The authors conclude by discussing implications of this principle for interpretation of results from binary choice tasks and future model development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Simon effect and its reversal in three-choice Hedge and Marsh tasks: Evidence for irrelevant stimulus-response compatibility and stimulus congruity.

In 2-choice A. Hedge and N. W. A. Marsh (1975) tasks or S. Komblum's (1992) Type-5 ensembles, irrelevant stimulus-response compatibility (SRC), logical recoding, display control arrangement correspondence (DCQ, and stimulus congruity are confounded. By using 3 response alternatives and both compatible and incompatible stimulus-response mappings, irrelevant SRC was pitted against logical recoding and both of them were disentangled from DCC and stimulus congruity. By varying response labels on a trial-by-trial basis and using different stimuli and responses, DCC and stimulus congruity were decoupled. Results from 4 experiments showed that neither logical recoding nor DCC contributes to the Simon effect and its reversal. Irrelevant SRC and stimulus congruity are necessary but neither is sufficient to account for the Simon effect and its reversal. A connectionist model of compatibility incorporating both irrelevant SRC and stimulus congruity appears to account for the results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automatic stimulus–response translation in dual-task performance.

In bottleneck models of overlapping-task performance, stimulus-response translation for secondary tasks is postponed until the primary response is selected. If this is so, then compatibility between the secondary and primary responses, or between the secondary response and the primary stimulus, should not affect primary-task performance. Yet such effects were demonstrated in 5 dual-task experiments combining primary manual and secondary vocal tasks: Pronounced effects of compatibility between the secondary and primary response and between the secondary response and primary stimulus were found on primary-task performance. The latter effect was also found with the lowest level of an extensive stimulus onset asynchrony variation, when the secondary task was not speeded, and even when the 2 tasks were performed on different trials. Findings suggest that secondary responses were activated before primary response selection was completed and thus support an automatic-translation hypothesis holding that, although eventual response selection may be serial, stimulus-response translation is performed in parallel. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous Cognitive Operations in Working Memory After Dual-Task Practice.

The authors tested the hypothesis that with adequate practice, people can execute 2 cognitive operations in working memory simultaneously. In Experiment 1, 6 students practiced updating 2 items in working memory through 2 sequences of operations (1 numerical, 1 spatial). In different blocks, imperative stimuli for the 2 sequences of operations were presented either simultaneously or sequentially. Initially, most participants experienced substantial dual-task costs. After 24 sessions of practice, operation latencies for simultaneous presentation were equal to the maximum of times for the 2 operations in the sequential condition, suggesting perfect timesharing. Experiment 2 showed that a reduction of dual-task costs requires practice on the combination of the 2 updating tasks, not just practice on each individual task. Hence, the reduction of dual-task costs cannot be explained by shortening or automatization of individual operations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Practice effects on two memory retrievals from a single cue.

The effects of practice on 2 retrievals from a single cue were investigated. In Experiment 1, participants were given extended single-task practice and were then tested on a dual memory retrieval task. Performance was consistent with a sequential retrieval model proposed by T. C. Rickard and H. Pashler (2003). In Experiment 2, participants practiced both single- and dual-retrieval tasks extensively. Initially, data from all participants indicated sequential retrieval. However, participants who grouped the 2 response outputs were eventually able to perform the dual task with a latency that approached the prediction of a parallel race model. Models that assume a transition from sequential to parallel retrieval with practice, along with other models that assume an immutable retrieval bottleneck at all practice levels, are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of task complexity and practice on performance after loss of sleep.

An experiment was conducted to assess the effects of degrees of task complexity and practice on performance after loss of sleep. The Ss were automatically presented every 7 sec. for 23 min., with cards containing 6 symbols. A symbol had to be chosen on the basis of certain rules. Some cards required 1 rule, some 2, some 3, and some 4. Group 1 was practiced after normal sleep and tested after 22 and 46 hr. without sleep. Group 2 was tested without sleep and without previous practice. Group 3 was practiced and tested after normal sleep. Loss of sleep had a greater effect after practice, but no clear differences emerged between the different levels of task complexity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

More on the Fragility of Performance: Choking Under Pressure in Mathematical Problem Solving.

In 3 experiments, the authors examined mathematical problem solving performance under pressure. In Experiment 1, pressure harmed performance on only unpracticed problems with heavy working memory demands. In Experiment 2, such high-demand problems were practiced until their answers were directly retrieved from memory. This eliminated choking under pressure. Experiment 3 dissociated practice on particular problems from practice on the solution algorithm by imposing a high-pressure test on problems practiced 1, 2, or 50 times each. Infrequently practiced high-demand problems were still performed poorly under pressure, whereas problems practiced 50 times each were not. These findings support distraction theories of choking in math, which contrasts with considerable evidence for explicit monitoring theories of choking in sensorimotor skills. This contrast suggests a skill taxonomy based on real-time control structures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Practice and working memory effects in building procedural skill.

Several theories assume that practice (a) results in restructuring of component processes and (b) reduces demand on working memory. Eight subjects practiced judgments about digital logic gates for over 8,000 trials. At two practice levels, subjects made judgments while retaining short-term memory loads irrelevant to the judgments, relevant but not accessed, or accessed to make the judgments. Four phenomena together provide constraints for theory: First, performance declined in moving from blocked practice to randomized practice. Second, gate and judgment type strongly affected latency. Third, these effects declined but did not disapppear with practice. Fourth, the cost of accessing information in working memory remained substantial. These results are interpreted as reflecting a serial process with constant structure, while component processes become faster. The results challenge theories assuming that all learning results from restructuring or that restructuring is an automatic consequence of practice, and they support a distributed view of working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning of event sequences is based on response-effect learning: Further evidence from a serial reaction task.

Four experiments provide converging evidence that serial learning in a serial reaction task is based on response–effect learning, mediated by the learning of the relations between a response and the stimulus that follows it. In Experiment 1, the authors varied the stimulus sequence and the response–stimulus relations while holding the response sequence constant. Learning effects depended on the complexity of the response–stimulus relations but not on the stimulus–stimulus relations. In Experiment 2, transfer of serial learning from 1 stimulus sequence to another was only found when both sequences had identical response–stimulus relations. In Experiment 3, a variation of the stimulus sequence alone had no effect on serial learning, whereas in Experiment 4 learning effects increased when the response–stimulus relations but not the stimulus–stimulus relations were simplified. These findings suggest that serial learning is based on mechanisms of voluntary action control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Competition and performance on a computer-based complex perceptual-motor task

Employees of temporary agencies practiced Space Fortress, a complex video game task, for 10 sessions, each consisting of 8 practice and 2 test games of 3 min each. Trainees practiced individually, in dyads, or in tetrads, and they were classified as having high or low aptitude based on computer attitude scores and baseline performance. Competition for monetary prizes was introduced early in training, late in training, or not at all. Competition facilitated high-aptitude trainees but not low-aptitude trainees. Group size and the timing of competition instructions had no main effects or interactions. The results are discussed in terms of social facilitation theory, according to which competition facilitates dominant responses, which helps high-skill trainees but not low-skill trainees.     

Working memory plasticity in old age: Practice gain, transfer, and maintenance.

Adult age differences in cognitive plasticity have been studied less often in working memory than in episodic memory. The authors investigated the effects of extensive working memory practice on performance improvement, transfer, and short-term maintenance of practice gains and transfer effects. Adults age 20-30 years and 70-80 years practiced a spatial working memory task with 2 levels of processing demands across 45 days for about 15 min per day. In both age groups and relative to age-matched, no-contact control groups, we found (a) substantial performance gains on the practiced task, (b) near transfer to a more demanding spatial n-back task and to numerical n-back tasks, and (c) 3-month maintenance of practice gains and near transfer effects, with decrements relative to postpractice performance among older but not younger adults. No evidence was found for far transfer to complex span tasks. The authors discuss neuronal mechanisms underlying adult age differences and similarities in patterns of plasticity and conclude that the potential of deliberate working memory practice as a tool for improving cognition in old age merits further exploration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)