Concurrent task effects on memory retrieval

Previous studies combining continuous free recall with a concurrent task have generally shown that concurrent tasks impose fairly negligible effects on memory retrieval. By contrast, dual-task studies employing either cued recall or semantic retrieval reveal gross memory impairment and suggest that retrieval is delayed by the centrally demanding phase of the concurrent tasks (i.e., response selection). To explore this conflict, subjects performed continuous free recall while carrying out a serial-choice#x2014; response time (RT) task, as in the previous free recall studies. Unlike these previous studies, however, the choice#x2014;RT task utilized arbitrary stimulus#x2014;response mappings in order to increase the proportion of time devoted to the centrally demanding response selection phase. Recall total was reduced significantly, and recall latency was slowed substantially.     

Concurrent cognitive task modulates coordination dynamics

Does a concurrent cognitive task affect the dynamics of bimanual rhythmic coordination? In‐phase coordination was performed under manipulations of phase detuning and movement frequency and either singly or in combination with an arithmetic task. Predicted direction‐specific shifts in stable relative phase from 0° due to detuning and movement frequency were amplified by the cognitive task. Nonlinear cross‐recurrence analysis suggested that this cognitive influence on the locations of the stable points or attractors of coordination entailed a magnification of attractor noise without a reduction in attractor strength. An approximation to these findings was achieved through parameter changes in a motion equation in relative phase. Results are discussed in terms of dual‐task performance as limited resources, dynamics rather than chronometrics, and reparameterization rather than degradation.     

Concurrent task performance enhances low-level visuomotor learning

Visuomotor association learning involves learning to make a motor response to an arbitrary visual stimulus. This learning is essential for visual search and discrimination performance and is reliant upon a well-defined neural circuit in the brain that includes the prefrontal cortex and the hippocampal formation. In the present study, we investigated the possible role of attentional processes during such learning using dual-task interference. A motor, verbal, or perceptual concurrent task was performed during the learning/training block of a simple visual discrimination task. Contrary to expectation, the dual-task groups showed improved learning and learning-dependent performance compared with untrained control and non-dual-task trained groups. A second experiment revealed that this effect did not appear to be due to increased arousal level; the inclusion of alerting tones during learning did not result in facilitation. These findings suggest that the engagement of attention, but not arousal, during the acquisition of a visuomotor association can facilitate this learning and its expression.     

Concurrent task interference in stutterers: dissociating hemispheric specialization and activation

Using all four combinations of hand and foot, adult stutterers and nonstutterers performed a unimanual sequential finger tapping task together with a stimulus-contingent foot responding task. The two groups were similar in that both demonstrated more dual-task interference when using the ipsilateral than contralateral limb pairs. Contrary to a prediction based on a hypothesis that attributes stuttering to neural interference due to an ungated or unregulated activity flow between the hemispheres, stutterers did not show more interference than nonstutterers when using the contralateral limb pairs. The groups did differ, however, in terms of finger tapping interference associated with right- versus left-foot concurrent task responding. Nonstutterers showed more interference when using the left than right foot. This was interpreted in terms of the attentional demands that the foot responding task placed on a system with an inherent left-hemisphere attentional bias. The lack of a reliable difference in stutterers with respect to interference by the two feet is consistent with indications from other research that stutterers have a relatively labile system of hemispheric attention or activation. The results of the study are placed into the context of a general model of the brain mechanisms associated with stuttering.     

Training and transfer effects in task switching

Performance on task switching, a paradigm commonly used to measure executive function, has been shown to improve with practice. However, no study has tested whether these benefits are specific to the tasks learned or are transferable to new situations. We report evidence of transferable improvement in a cued, randomly switching paradigm as measured by mixing cost, but we report no consistent improvement for switch cost. Improvement in mixing costs arises from a relative reduction in time to perform both switch and nonswitch trials that immediately follow switch trials, implicating the ability to recover from unexpected switches as the source of improvement. These results add to a growing number of studies demonstrating generalizable improvement with training on executive processing.     

Goal-performance relations: The effects of initial task complexity and task practice

The current study was conducted to examine the effects of task complexity and task practice (trials) on the goal-performance relationship. Specific, difficult goal assignments were predicted to enhance performance on a complex task only in later task practice. On a simpler task, specific, difficult goal assignments were predicted to enhance performance in early task practice and to disrupt performance in later task practice. The results indicated that goals exerted the predicted effects in the simple task version but had no effect in the complex task version. Possible relationships between amount of task practice and stages of skill acquisition are discussed for tasks differing in complexity. The results are also discussed in terms of cognitive resource demands and self-regulatory processes. Implications for the effectiveness of goals in relation to task complexity and task trials are also discussed.This article is based on the senior author's dissertation at the University of Minnesota. We thank Milt Hakel, Allan Jones, and Bart Osburn for their helpful comments on earlier drafts. The authors also wish to thank Phil Ackerman and John Campbell for their insightful comments throughout the research project and other members of the dissertation committee: Rich Arvey, Mark Davisson, and Marvin Dunnette.This research was partially supported by the Air Force Office of Scientific Research Project LAMP, under the auspices of the Air Force Human Resources Laboratory (contract AFOSR-87-0234) and by a Research Initiation Grant from the University of Houston.Portions of this data were presented at the American Psychological Association Meetings, Atlanta, 1988.     

Analogical transfer in the THOG task

The influences of surface and structural similarity on analogical transfer were examined with 318 undergraduate participants in four experiments using Needham and Amado's (1995) Pythagoras THOG problem as the source problem and Wason's standard abstract THOG task as the target problem. In Experiments 1-3, systematic changes in surface similarity between the source and target problems were introduced by changing the named exemplar, the dimensional values, and the dimensions, respectively, in the target problem. Significant transfer was obtained in all three experiments. In Experiment 4, we explored the basis of this transfer by examining three versions of the Pythagoras THOG problem, factorially combining its facilitating features as source problems. Results indicated that the inclusion of a hypothesis generation request was necessary for significant transfer. The implications of our findings for using transfer versus facilitation as the performance criterion for deductive reasoning are considered.     

Facilitation and analogical transfer in the THOG task

This study was concerned with Wason's THOG task, a hypothetico-deductive reasoning problem for which performance is typically very poor (<20% correct). Recently, however, Needham and Amado (1995) and Koenig and Griggs (2004) have observed both facilitation and spontaneous analogical transfer effects for the Pythagoras version of this task. Based on their findings, Koenig and Griggs concluded that in addition to the separation of the data (the properties of the designated THOG) from the hypotheses that need to be generated (the possible combinations of properties written down), an explicit request to generate these hypotheses is necessary to obtain significant analogical transfer. In the present study we extended the generalisability of this conclusion in three experiments with 214 undergraduate participants using O'Brien et al.'s (1990) Blackboard version of the task. We discuss the relationship of the results to dual process theories of reasoning and propose that analogical transfer may be a better criterion than task facilitation for judging participants' task understanding.     

Effect of task similarity on transfer performance

Transfer of training was studied using a discrete tracking task which involved aiming at targets on a moving paper strip. The effects of target speed, target size, and task demand, (number of targets aimed at in each trial) were examined separately in three experiments. In Experiment 1, a difference in stimulus input (i.e., target speed) produced large differences in task strategy (i.e., speed vs. accuracy bias). No significant transfer was found. A difference in target size (Experiment 2) involves a change in stimulus input, but this did not result in large strategy differences. Significant transfer was found when transferring from large to small targets. In Experiment 3, a variation in task demand produced different task strategies without a change in stimulus input. Significant transfer was found in all groups. The results were discussed in terms of similarity in perceptual elements and task strategy between transfer and training tasks. Greater similarity overall led to greater transfer.     

Extended practice with a single-character classification task

Extended practice was given on a single-character classification task with four nested checklists of Sizes 1, 2, 4, and 8 defining positive sets. Reaction time reduces with practice, but is linear with the logarithm of checklist size at all stages of training, and transfers to characters of large size and different case.     

Asymmetric transfer effects between cognitive and affective task disturbances

Task-irrelevant features of a stimulus can disturb performance on a given task, and this can occur for cognitive reasons such as irrelevant stimulus position, and affective reasons such as high stimulus valence. The human brain adapts to such disturbances in order to ensure successful task performance. Adaptations can occur in a transient manner in response to recent events, and they can also be sustained to account for overall probabilities of disturbances. Here, we study the mutual interplay between affective and cognitive task disturbances under conditions of sustained conflict adaptation. More precisely, we examined the trajectory of finger movements in a speeded classification task and investigated whether adaptation to a high probability of spatial disturbances transfers to the impact of affective disturbances (Experiment 1) and whether adaptation to a high probability of affective disturbances transfers to the impact of spatial disturbances (Experiment 2). Our observations point towards an asymmetric transfer from adaptation to affective onto the processing of cognitive disturbances, but not the other way around.     

Repetition and practice effects in a lexical decision task

Ss classified visually presented verbal units into the categories “in your vocabulary” or “not in your vocabulary.” The primary concern of the experiment was to determine if making a prior decision on a given item affects the latency of a subsequent lexical decision for the same item. Words of both high and low frequency showed a systematic reduction in the latency of a lexical decision as a consequence of prior decisions (priming) but did not show any reduction due to nonspecific practice effects. Nonwords showed no priming effect but did show shorter latencies due to nonspecific practice. The results also indicated that many (at least 36) words can be in the primed state simultaneously and that the effect persists for at least 10 min. The general interpretation was that priming produces an alteration in the representation of a word in memory and can facilitate the terminal portion of the memory search process which is assumed to be random.     

A task for use in decision-making research and practice

This study was designed to refine the Decision-Making Questionnaire (DMQ) developed in earlier research for ease of use. Previous work had indicated that the longer forms of the DMQ, whilst reasonably reliable and valid, were too lengthy to be easily incorporated into research and practice. Sixtythree individual workers from different organizations participated in this study by completing the 10-scenario DMQ, which takes about 45 minutes. A series of analyses indicated how this 10-scenario scale was most effectively reduced to a two-scenario scale, which takes less than 15 minutes to complete. The results are discussed in terms of their research value and practical utility. The Decision-Making Task and its scoring protocol are appended.     

OPTIMAL practice conditions enhance the benefits of gradually increasing error opportunities on retention of a stepping sequence task

IntroductionPhysical therapists should implement practice conditions that promote motor skill learning after neurological injury. Errorful and errorless practice conditions are effective for different populations and tasks. Errorful learning provides opportunities for learners to make task-relevant choices. Enhancing learner autonomy through choice opportunities is a key component of the Optimizing Performance through Intrinsic Motivation and Attention for Learning (OPTIMAL) theory of motor learning. The objective of this study was to evaluate the interaction between error opportunity frequency and OPTIMAL (autonomy-supportive) practice conditions during stepping sequence acquisition in a virtual environment.MethodsForty healthy young adults were randomized to autonomy-supportive or autonomy-controlling practice conditions, which differed in instructional language, focus of attention (external vs internal) and positive versus negative nature of verbal and visual feedback. All participants practiced 40 trials of 4, six-step stepping sequences in a random order. Each of the 4 sequences offered different amounts of choice opportunities about the next step via visual cue presentation (4 choices; 1 choice; gradually increasing [1-2-3-4] choices, and gradually decreasing [4-3-2-1] choices). Motivation and engagement were measured by the Intrinsic Motivation Inventory (IMI) and the User Engagement Scale (UES). Participants returned 1–3 days later for retention tests, where learning was measured by time to complete each sequence. No choice cues were offered on retention.ResultsParticipants in the autonomy-supportive group outperformed the autonomy-controlling group at retention on all sequences (mean difference 2.88s, p < .005, t[6835] = 3.42). Participants in both groups had the most difficulty acquiring the decreasing choice (4-3-2-1) sequence (p < .001, t[6835] = −4.26) and performed most poorly on the errorful (4 choice) sequence (p < .034, t[6835] = 2.65) at retention. Participants in the autonomy-supportive group performed best at retention on the increasing choice (1-2-3-4) sequence (p < .033, t[6835] = −2.7). Participants in both groups who reported greater attention to the task on the UES Average Focused Attention subscale during acquisition had poorer retention performance, particularly for the decreasing choice (4-3-2-1) sequence (p < .005, t(6835) = 3.39). Participants in the autonomy-supportive group reported significantly higher overall motivation (p = .007, t(38) = 0.728, d = 0.248) on the IMI as compared to the autonomy-controlling group.ConclusionIndividual benefits of errorless learning and autonomy-supportive practice conditions, with an interaction effect for practice that begins errorless but adds increasing error opportunities over time, suggest that participants relied on implicit learning strategies for this full body task and that feedback about successes minimized errors and reduced their potential information-processing benefits. Subsequent work will continue to examine how assigning a positive versus a negative quality to error provision influences the benefits of errorful learning in a variety of tasks.     

Concurrent task effects on memory encoding and retrieval: Further support for an asymmetry

Several studies have demonstrated that divided attention at encoding significantly reduces memory performance, whereas divided attention at retrieval affects memory performance only minimally. However, the possibility exists that retrieval processes have shown such resilience because the concurrent tasks used have often not been very demanding. To assess this possibility, we used independent manipulations of the concurrent task during either encoding or retrieval that included stimulus-response compatibility and participant- versus experimenter-controlled pace. In addition, we manipulated the distribution of practice that the participants received with the primary and the concurrent tasks. The results replicated and extended those recently reported by Rohrer and Pashler (2003), indicating that although memory performance is negatively affected by divided attention at retrieval, especially with noncompatible stimulus-response mapping in the concurrent task, this effect was much smaller than that at encoding, in line with the asymmetry notion. Furthermore, experimenter versus participant control of the concurrent task had no effect on memory retrieval. Finally, under conditions of equal practice with both the memory and the concurrent tasks, memory retrieval was affected only to a small degree. In contrast to encoding processes, the processes involved in retrieval accuracy appear, in many cases, to be less interrupted by divided attention, although this protection requires substantial resources.     

Concurrent schedules: undermatching and control by previous experimental conditions.

Five pigeons were trained on concurrent variable-interval schedules. A series of conditions in which the ratio of reinforcement rates on two keys was progressively increased and then decreased was arranged twice. The birds were then exposed to an irregular sequence of conditions. Each condition in which reinforcement was available on both keys lasted six sessions. Performance in the first, third, and sixth sessions after a condition change was analyzed. Following a condition change, preference was biased toward the preference in the last condition, but this effect largely disappeared before the sixth session of training. The birds' preferences also appeared less sensitive to reinforcement rates in early sessions after a transition. Preference in a session was a function of both the reinforcements in that session and the reinforcements obtained in as many as four or five previous sessions. The effects of reinforcements in previous sessions could be summarized by the performance in the immediately preceding session, giving a relatively simple relation between present performance and a combination of present reinforcement and prior session performance. While such hysteresis could cause undermatching when only a small number of sessions are arranged in a condition, undermatching in a stable-state performance probably arises elsewhere.     

Production of negative transfer in a problem-solving task

72 students solved two problems using a source problem designed to inhibit performance on the target problem relative to baseline performance when the target problem was solved alone. Both source and target problems shared surface similarity but were structurally dissimilar. Negative transfer was found for three different source and target combinations. The decreased performance below baseline for three of the source-target programs provides a reliable context to demonstrate negative transfer and facilitate continued investigation of this phenomenon.     

The effects of recent practice on task switching

Four experiments investigated the effect of recent selective practice on the cost of switching between 2 tasks afforded by letter-digit pairs: alphabet arithmetic and shape comparison. Experiments 1 and 2 found a greater cost associated with switching to the more recently practiced task: evidence that task-set inertia contributes to switching costs. Experiment 3 found this effect to be limited to trials on which a recently trained stimulus followed another such stimulus: a result problematic for all current theories of task-set priming. Experiment 4 showed that the effect of recent practice was eliminated by active preparation for a task switch: It appears that endogenous task-set preparation reduces the effects of task-set inertia. ((c) 2003 APA, all rights reserved)