Response-based strengthening in task shifting: Evidence from shift effects produced by errors.

The hypothesis is introduced that 1 source of shift costs is the strengthening of task-related associations occurring whenever an overt response is produced. The authors tested this account by examining shift effects following errors and error compensation processes. The authors predicted that following a specific type of error, called task confusion, shift benefits instead of shift costs should result. A series of 3 experiments confirmed this prediction showing that task confusions produce shift benefits in subsequent trials (Experiment 1), even when the error is detected (Experiment 2). Moreover, only posterror processes that imply an error correction response produce shift costs (Experiment 3). These results additionally suggest that error detection cannot prevent errors from affecting subsequent performance. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Modeling behavioral measures of error detection in choice tasks: Response monitoring versus conflict monitoring.

The present study investigated the mechanisms underlying error detection in the error signaling response. The authors tested between a response monitoring account and a conflict monitoring account. By implementing each account within the neural network model of N. Yeung, M. M. Botvinick, and J. D. Cohen (2004), they demonstrated that both accounts make different predictions as to how error signaling performance is influenced by varying the participants' response criterion. These predictions were tested in an experiment using the Eriksen-flanker task. The qualitative pattern as well as a model fit favored the response monitoring account, which states that error detection is mediated by detecting internal error corrections. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement error in psychological research: Lessons from 26 research scenarios.

As research in psychology becomes more sophisticated and more oriented toward the development and testing of theory, it becomes more important to eliminate biases in data caused by measurement error. Both failure to correct for biases induced by measurement error and improper corrections can lead to erroneous conclusions that retard progress toward cumulative knowledge. Corrections for attenuation due to measurement error are common in the literature today and are becoming more common, yet errors are frequently made in this process. Technical psychometric presentations of abstract measurement theory principles have proved inadequate in improving the practices of working researchers. As an alternative, this article uses realistic research scenarios (cases) to illustrate and explain appropriate and inappropriate instances of correction for measurement error in commonly occurring research situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling performance at the trial level within a diffusion framework: A simple yet powerful method for increasing efficiency via error detection and correction.

When faced with a relatively novel task, it is reasonable to assume that increases in performance efficiency depend upon processing adjustments that occur in response to errant or suboptimal performance. For such dynamic corrections to occur, the errors must first be noted, which can be challenging in contexts where no external feedback is provided. In the present article, the authors describe how a “double cross” error monitoring and correction process can be added to diffusion models of binary decision. The authors first outline the logick of our proposed error detection system, and then demonstrate that the addition of this double-cross process in the context of a simulation of lexical decision leads to more efficient responding. That is, with such a mechanism in place, the model was able to gradually respond more quickly and the distribution of errors became more consistent with human response patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Erroneous knowledge of results affects decision and memory processes on timing tasks.

On mental timing tasks, erroneous knowledge of results (KR) leads to incorrect performance accompanied by the subjective judgment of accurate performance. Using the start-stop technique (an analogue of the peak interval procedure) with both reproduction and production timing tasks, the authors analyze what processes erroneous KR alters. KR provides guidance (performance error information) that lowers decision thresholds. Erroneous KR also provides targeting information that alters response durations proportionately to the magnitude of the feedback error. On the production task, this shift results from changes in the reference memory, whereas on the reproduction task this shift results from changes in the decision threshold for responding. The idea that erroneous KR can alter different cognitive processes on related tasks is supported by the authors' demonstration that the learned strategies can transfer from the reproduction task to the production task but not visa versa. Thus effects of KR are both task and context dependent. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional properties of primate putamen neurons during the categorization of tactile stimuli

We used psychometric techniques and neurophysiological recordings to study the role of the putamen in somesthetic perception. Four monkeys were trained to categorize the speed of moving tactile stimuli. Animals performed a task in which one of two target switches had to be pressed with the right hand to indicate whether the speed of probe movement across the glabrous skin of the left, restrained hand was low or high. During the task we recorded the activity of neurons in the putamen contralateral (right) and ipsilateral (left) to the stimulated hand. We found different types of neuronal responses, all present in the right and left putamen. Some neurons responded during the stimulus period, others responded during the hand-arm movement used to indicate categorization, and others responded during both of these periods. The responses of many neurons did not vary either with the speed of the stimuli or in relation to the categorization process. In contrast, neurons of a particular type responded differentially: their activity reflected whether stimulus speed was low or high. These differential responses occurred during the stimulus and hand-arm motion periods. A number of the nondifferential and differential neurons were studied when the same stimuli used in the categorization task were delivered passively. Few neurons with nondifferential discharges, and none of the differential neurons, responded in this condition. In a visually cued control task we studied the possibility that the differential responses were associated with the intention to press or with the trajectory of the hand to one of the target switches. In this condition, a light turned on instructed the animal which target switch to press for a reward. Very few neurons in both hemispheres maintained the differential responses observed during the categorization task. Those neurons that discharged selectively for low or high speeds were analyzed quantitatively to produce a measure comparable with the psychometric function. The thresholds of the resulting neurometric curves for the neuronal populations were very similar to the psychometric thresholds. The activity of a large fraction of these neurons could be used to accurately predict whether the stimulus speed was low or high. The results indicate that the putamen, both contralateral and ipsilateral to the stimulated hand, contains neurons that discharge in response to the somesthetic stimuli during the categorization task. Those neurons that respond irrespective of the stimulus speed appear to be involved in the general sensorimotor behavior of the animal during the execution of the task. The results suggest that the putamen may play a role in bimanual tasks. The recording of neurons in the right and left putamen whose activities correlate with the speed categories suggests that this region of the basal ganglia, in addition to its role in motor functions, is also involved in the animal's decision process.     

"Rhythms and responses": Correction to Kolers and Brewster.

Reports an error in "Rhythms and responses" by Paul A. Kolers and Joan M. Brewster (Journal of Experimental Psychology: Human Perception and Performance, 1985[Apr], Vol 11[2], 150-167). There is a typographical error on page 153. A correction to this error has been provided in the erratum. (The following abstract of the original article appeared in record 1986-05383-001.) Tested the assumption that there is a central clock coordinating behavior in all sensory modalities and response modes. A rhythmic tapping task was used in 3 experiments in which 12 undergraduates first attempted to synchronize responses with brief auditory, tactile, or visual stimuli and then continued to tap at the same rate on their own. Performance was most variable with visual stimuli and least variable with auditory stimuli. Results suggest that performances were not based on a common clock and that different strategies were employed when the task was presented in different modalities. The hypothesis of a single timing mechanism controlling behavior is rejected, and the validity is questioned of information processing models that are formulated without regard to temporal relations among their conjectured processes. Discussion focuses on the relation between successive responses and the means by which timing is accomplished. (56 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Matching patterns of activity in primate prefrontal area 8a and parietal area 7ip neurons during a spatial working memory task

Single-unit recording studies of posterior parietal neurons have indicated a similarity of neuronal activation to that observed in the dorsolateral prefrontal cortex in relation to performance of delayed saccade tasks. A key issue addressed in the present study is whether the different classes of neuronal activity observed in these tasks are encountered more frequently in one or the other area or otherwise exhibit region-specific properties. The present study is the first to directly compare these patterns of neuronal activity by alternately recording from parietal area 7ip and prefrontal area 8a, under the identical behavioral conditions, within the same hemisphere of two monkeys performing an oculomotor delayed response task. The firing rate of 222 posterior parietal and 235 prefrontal neurons significantly changed during the cue, delay, and/or saccade periods of the task. Neuronal responses in the two areas could be distinguished only by subtle differences in their incidence and timing. Thus neurons responding to the cue appeared earliest and were more frequent among the task-related neurons within parietal cortex, whereas neurons exhibiting delay-period activity accounted for a larger proportion of task-related neurons in prefrontal cortex. Otherwise, the task-related neuronal activities were remarkably similar. Cue period activity in prefrontal and parietal cortex exhibited comparable spatial tuning and temporal duration characteristics, taking the form of phasic, tonic, or combined phasic/tonic excitation in both cortical populations. Neurons in both cortical areas exhibited sustained activity during the delay period with nearly identical spatial tuning. The various patterns of delay-period activity-tonic, increasing or decreasing, alone or in combination with greater activation during cue and/or saccade periods-likewise were distributed to both cortical areas. Finally, similarities in the two populations extended to the proportion and spatial tuning of presaccadic and postsaccadic neuronal activity occurring in relation to the memory-guided saccade. The present findings support and extend evidence for a faithful duplication of receptive field properties and virtually every other dimension of task-related activity observed when parietal and prefrontal cortex are recruited to a common task. This striking similarity attests to the principal that information shared by a prefrontal region and a sensory association area with which it is connected is domain specific and not subject to hierarchical elaboration, as is evident at earlier stages of visuospatial processing.     

Correcting a metacognitive error: Feedback increases retention of low-confidence correct responses.

Previous studies investigating posttest feedback have generally conceptualized feedback as a method for correcting erroneous responses, giving virtually no consideration to how feedback might promote learning of correct responses. Here, the authors show that when correct responses are made with low confidence, feedback serves to correct this initial metacognitive error, enhancing retention of low-confidence correct responses. In 2 experiments, subjects took an initial multiple-choice test on general knowledge facts and made a confidence judgment after each response. Feedback was provided for half of the questions, and retention was assessed by a final cued-recall test. Taking the initial test improved retention relative to not testing, and feedback further enhanced performance. Consistent with prior research, feedback improved retention by allowing subjects to correct initially erroneous responses. Of more importance, feedback also doubled the retention of correct low-confidence responses, relative to providing no feedback. The function of feedback is to correct both memory errors and metacognitive errors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Changes in error types over learning stages.

Classified misconceptions about mathematical procedures in signed-number addition problems into several categories to facilitate the investigation of changes in these errors at different times and the design of remedial instruction. The classification was first done by examining which of the procedural steps were correctly completed by each erroneous rule. An index was defined that measures how early or how late in the procedural tree (or network) an erroneous rule causes departure from the correct steps; an early derailment obviously has more serious consequences than one at a later stage. Erroneous rules, formed because of a misconception or lack of understanding at earlier stages of the procedural network, formed a single group and showed properties different from all other rules. An experiment with 45 7th graders demonstrated that the use of correct rules was related to verbal ability and increased over 6 tests over a 14-mo period. The decline in error scores appeared to be related to increasing mental maturity rather than the effects of instruction. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monkey hippocampal neuron responses related to spatial and non-spatial influence

Activity in the monkey hippocampal formation (HF) was analyzed during movement guided by auditory and visual cues. The monkey could control a motorized cab by pressing the proper 1 of 4 available levers within a 2.5 x 2.5 m field. Of 238 HF neurons analyzed, responses of 79 were place related and responses of 110 were task related. Of the task-related neurons, 33 were also place related, and responded to task cues only where place-related responses occurred. The results suggest HF gating of incoming non-spatial information, depending on information about location.     

Attention is required for acquisition but not expression of new response biases.

Throughout a lifetime of interaction with the physical environment, people develop a strong bias to respond on the same side as the location of a target object, even when its location is irrelevant to the task at hand. Recent research has shown that this compatibility bias can be overridden with relatively brief but focused training. To better understand how such training affects preexisting response biases, we investigated whether attention is required to acquire and express a new bias to respond on the opposite side, thus creating an incompatibility bias. Participants practiced making responses on the opposite side from left and right tones and then made responses based on the frequencies (high or low) of the same tones. As in previous research, practice with a spatially incompatible mapping eliminated the compatible bias in the Simon task. The addition of an attention load (continuous secondary tracking task) during practice prevented learning the new response bias. However, once the new bias was learned, it overrode the compatibility bias regardless of available attentional resources. We suggest that not only can a quickly learned response bias overwhelm preexisting biases that are acquired over years of experience but that recently learned and older, preexisting biases are similarly affected by attention load. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Rhythms and responses.

[Correction Notice: An erratum for this article was reported in Vol 11(5) of Journal of Experimental Psychology: Human Perception and Performance (see record 2008-10975-001). There is a typographical error on page 153. A correction to this error has been provided in the erratum.] Tested the assumption that there is a central clock coordinating behavior in all sensory modalities and response modes. A rhythmic tapping task was used in 3 experiments in which 12 undergraduates first attempted to synchronize responses with brief auditory, tactile, or visual stimuli and then continued to tap at the same rate on their own. Performance was most variable with visual stimuli and least variable with auditory stimuli. Results suggest that performances were not based on a common clock and that different strategies were employed when the task was presented in different modalities. The hypothesis of a single timing mechanism controlling behavior is rejected, and the validity is questioned of information processing models that are formulated without regard to temporal relations among their conjectured processes. Discussion focuses on the relation between successive responses and the means by which timing is accomplished. (56 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An unbiased correction for sampling error in validity generalization studies.

A correction for variance due to sampling error is part of all the statistical procedures used to study validity generalization. This correction is analogous to estimation of a variance component in a random effects analysis of variance. The correction usually has a large influence on the results of validity generalization analyses. James, Demaree, and Mulaik (1986) recently questioned the correction for sampling error, suggesting that several of the assumptions required for its derivation are questionable. In this article, I provide an alternative correction for sampling error that is shown to be (exactly) unbiased. A comparison of the calculations involved in the computation of the unbiased correction with the calculations involved in the calculation of the usual correction suggests that the 2 corrections will rarely differ substantially. Hence, the usual correction is not seriously biased. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do the hemispheres watch each other? Evidence for a between-hemispheres performance monitoring.

This study tested the hypothesis that when tasks are complex, response selection and performance monitoring are divided across the hemispheres, and when tasks are simple, response selection and error monitoring are done in the same hemisphere. Using a divided visual field paradigm, the authors presented a target and an interference stimulus, either to the same visual field or to different visual fields, and encouraged error correction. The interference stimulus was timed to interfere with posited error processing. Four tasks were used: bar graph identification, lexical decision, and complex and simple versions of the flankers task. The first three tasks revealed a pattern of contralateral interference, suggesting that error processing occurred in the hemisphere that did not process the initial target. The fourth task showed ipsilateral interference, suggesting that the same hemisphere processed the target and monitored itself. The authors conclude that the pattern of hemispheric cooperation in error processing is affected by task complexity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Awareness of errors in naturalistic action after traumatic brain injury

A prospective study was performed to develop a method for assessing "on-line" error detection and correction during performance of naturalistic action, to determine whether traumatic brain injury (TBI) affects error detection and correction, and to compare actual task performance with verbal self-ratings of performance. Participants included 18 persons who had sustained severe TBI from 34 to 186 days prior to study and who were comparable to controls in their rate of naturalistic action error, along with 18 control subjects chosen to be demographically comparable to subjects with TBI. Subjects performed two different tests of naturalistic action in which they completed everyday activities (eg, wrapping a gift, making toast) at different levels of complexity, as manipulated by the addition of distractor objects, the number of tasks that had to be completed per trial, and other demands on planning and working memory. Using a specially developed coding system, each error on these tasks was scored as to whether the subject corrected it and whether the subject otherwise demonstrated awareness of the error. Error scores were also compared to subjects' responses to a questionnaire in which they rated their own performance on the most challenging level of the naturalistic action test. In general, subjects with TBI corrected and showed awareness of proportionally fewer of their errors when compared to controls. Qualitative patterns for some error types also differed between groups. Despite making more errors than control subjects on the most challenging task, subjects with TBI did not rate themselves as performing more poorly with respect to its cognitive demands. However, for subjects with TBI, the number of errors was correlated with performance ratings on certain questionnaire items. This study showed that error detection and correction can be reliably measured during naturalistic action and appear to be impaired in severe TBI even when the base rate of error is controlled. TBI may affect error detection and correction by reducing, or impairing the allocation of, attentional resources needed for the simultaneous execution and monitoring of routine action.     

Asymmetries in the preparation and control of manual aiming movements.

Conducted 2 experiments with 20 undergraduates to determine if typical right hand target aiming advantages could be reduced or eliminated by increasing the spatial demands of the aiming task. In Exp 1, right hand advantages were found for both movement time and error regardless of spatial characteristics of the task. When a greater degree of spatial uncertainty was introduced in Exp 2, Ss exhibited a left hand reaction time advantage. Taken together, results suggest that the right cerebral hemisphere may have a special role to play in preparing the spatial aspects of an aiming movement, while the left hemisphere is more important for movement execution. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development and application of a nonaqueous capillary electrophoresis system for the analysis of porphyrins and their oligomers (PHOTOFRIN)

We analyzed 577 neurons recorded from visual areas V1, V2, V4, and the inferotemporal area (TEO) of macaque monkeys, which performed a visual fixation task and a spot-off-on (blink) test during the fixation period. Among these neurons, 35% were defined as task-related cells, because they gave responses at the task-start, fixation, or task-end periods but were unresponsive to the spot blink, which was physically identical to these stimuli. Blink-responsive cells accounted for 29% and task-unresponsive cells for 30% of the neurons. The task-related response was large and frequent in V4 (34%) and TEO (41%), but small and less frequent in V1 (31%) and V2 (27%). Other observations further demonstrated nonsensory activities in these areas: In some cells, response to the fixation spot was inhibitory, whereas light stimulation on the fovea was excitatory; some V1 and V2 cells had color-irrelevant responses, and some cells responded to the spot-off only when the monkey regarded it as a task-end cue.     

Speech-induced changes in corticospinal excitability

The aim of the experiments was to investigate the effects of speech on the excitability of corticospinal pathways to human hand muscles. Single transcranial magnetic stimuli were given randomly over the hand area of either the left or right motor cortex of 10 right-handed and 3 left-handed normal volunteers. Electromyographic responses were recorded in the relaxed first dorsal interosseous muscle while the subjects (a) read aloud a piece of text, (b) read silently, (c) spoke spontaneously, or (d) made sounds without speaking. The only consistent effect across subjects occurred during task a, which significantly increased the size of responses evoked in the dominant hand of all subjects, but had either no effect (8 subjects) or a smaller effect in the nondominant hand. Tasks b and d had no reliable effect, whereas task c tended to increase response size in both hands. Control measurements suggest that the effects in task a were caused by changes in cortical rather than spinal excitability. This is the first demonstration of lateralized speech effects on the excitability of cortical arm areas. The results provide a useful adjunct to other tests of cerebral dominance, using only single- rather than repetitive-pulse cortical stimulation.     

Response selection and response execution in task switching: Evidence from a go-signal paradigm.

The present study used a go/no-go signal delay (GSD) to explore the role of response-related processes in task switching. A go/no-go signal was presented at either 100 ms or 1,500 ms after the stimulus. Participants were encouraged to use the GSD for response selection and preparation. The data indicate that the opportunity to select and prepare a response (i.e., long GSD) resulted in a substantial reduction of task-shift costs (Experiment 1) and n-2 task-repetition costs (i.e., backward inhibition; Experiment 2) in the current trial. These results suggest that interference from the preceding trial can be resolved during response selection and preparation. Furthermore, the shift costs and the n-2 repetition costs after no-go trials with long GSD (i.e., response selection but no execution) were markedly smaller than after go trials. These findings suggest that the interference that gives rise to shift costs and n-2 repetition costs is related not solely to response selection but also to response execution. Thus, the present study demonstrates dissociable contributions of response selection and response execution to interference effects in task switching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)