Speeded Choice Tasks Research Articles

Motor inhibition errors and interference suppression errors differ systematically on neural and behavioural features of response monitoring

Action inhibition and error commission are prominent in everyday life. Inhibition comprises at least two facets: motor inhibition and interference suppression. When motor inhibition fails, a strong response impulse cannot be inhibited. When interference suppression fails, we become distracted by irrelevant stimuli. We investigated the neural and behavioural similarities and differences between motor inhibition errors and interference suppression errors systematically from stimulus-onset to post-response adaptation. To enable a direct comparison between both error types, we developed a complex speeded choice task where we assessed the error types in two perceptually similar conditions. Comparing the error types along the processing stream showed that the P2, an early component in the event-related potential associated with sensory gating, is the first marker for differences between the two error types. Further error-specific variations were found for the parietal P3 (associated with context updating and attentional resource allocation), for the lateralized readiness potential (LRP, associated with primary motor cortex activity), and for the Pe (associated with error evidence accumulation). For motor inhibition errors, the P2, P3 and Pe tended to be enhanced compared to successful inhibition. The LRP for motor inhibition errors was marked by multiple small response impulses. For interference suppression errors, all components were more similar to those of successful inhibition. Together, these findings suggest that motor inhibition errors arise from a deficient early inhibitory process at the perceptual and motor level, and become more apparent than interference suppression errors, that arise from an impeded response selection process.

Vision rivals audition in alerting humans for fast action

Successful behaviour requires that humans act promptly upon the ubiquitous rapid changes in the environment. Prompt actions are supported by phasic alertness, the increased readiness for perception and action elicited by warning stimuli (alerting cues). Audition is assumed to induce phasic alertness for action faster and more strongly than other senses. Here, we show that vision can be equally effective as audition. We investigated the temporal evolution and the effectiveness of visual and auditory alerting for action in a speeded choice task, while controlling for basic sensitivity differences between the modalities that are unrelated to action control (by matching auditory and visual stimuli according to reaction times in a prior simple detection task). Results revealed that alerting sped up responses, but this happened equally fast and equally strong for visual and auditory alerting cues. Thus, these findings argue that vision rivals audition in phasic alerting for prompt actions, and suggest that the underlying mechanisms work across both modalities.

Slow and steady? Strategic adjustments in response caution are moderately reliable and correlate across tasks.

Speed-accuracy trade-offs are often considered a confound in speeded choice tasks, but individual differences in strategy have been linked to personality and brain structure. We ask whether strategic adjustments in response caution are reliable, and whether they correlate across tasks and with impulsivity traits. In Study 1, participants performed Eriksen flanker and Stroop tasks in two sessions four weeks apart. We manipulated response caution by emphasising speed or accuracy. We fit the diffusion model for conflict tasks and correlated the change in boundary (accuracy – speed) across session and task. We observed moderate test-retest reliability, and medium to large correlations across tasks. We replicated this between-task correlation in Study 2 using flanker and perceptual decision tasks. We found no consistent correlations with impulsivity. Though moderate reliability poses a challenge for researchers interested in stable traits, consistent correlation between tasks indicates there are meaningful individual differences in the speed-accuracy trade-off.

Testing the bottleneck account for post-error slowing beyond the post-error response

The bottleneck account for post-error slowing assumes that cognitive resources are depleted after errors and thus the processing of subsequent events is delayed. To test this, we used a novel speeded-choice task and recorded behavioral measures and ERP (event-related potential) components on five trials following either an erroneous or correct response. We found that participants were slower and less accurate immediately after making an error and that this reduction of performance decayed on the following trials. Moreover, post-correct versus post-error differences in both the visual N1 and the P3 component were found. However, the difference in the P3 component rapidly diminished over time, whereas the differences in the N1 component were still evident in the fourth trial following the erroneous response. The results lay further support to the bottleneck account for post-error slowing and show a combination of early attentional and higher-order processing changes that occur after erroneous responses.

Neural signatures of adaptive post-error adjustments in visual search

Errors in speeded choice tasks can lead to post-error adjustments both on the behavioral and on the neural level. There is an ongoing debate whether such adjustments result from adaptive processes that serve to optimize performance or whether they reflect interference from error monitoring or attentional orientation. The present study aimed at identifying adaptive adjustments in a two-stage visual search task, in which participants had to select and subsequently identify a target stimulus presented to the left or right visual hemifield. Target selection and identification can be measured by two distinct event-related potentials, the N2pc and the SPCN. Using a decoder analysis based on multivariate pattern analysis, we were able to isolate the processing stages related to error sources and post-error adjustments. Whereas errors were linked to deviations in the N2pc and the SPCN, only for the N2pc we identified a post-error adjustment, which exhibits key features of source-specific adaptivity. While errors were associated with an increased N2pc, post-error adjustments consisted in an N2pc decrease. We interpret this as an adaptive adjustment of target selection to prevent errors due to disproportionate processing of the task-irrelevant target location. Our study thus provides evidence for adaptive post-error adjustments in visual search.

Negative effects of an alternating-bias training aimed at attentional flexibility: a single session study

ABSTRACTAttentional Bias Modification (ABM) usually aims to induce automatic biases directed toward or away from certain stimulus categories. An alternative approach, termed Attention Control Training (ACT), uses a similar paradigm but aims to train the ability to exert top-down control over attention and downregulate bottom-up interference. The current study tested a novel Alternating Bias training aimed at training attention control rather than a bias. The training involved switching contingencies, so that the optimal attentional set alternated per block. Assessment and training tasks used neutral and angry faces as emotional stimuli. Results indicated that, rather than improving attention control, the Alternating Bias condition led to increased sensitivity to emotional stimuli, as measured via self-reported emotional reactivity and an Emotional Speeded Choice task. This was interpreted as an effect of enhanced salience: in the Alternating Bias condition, as with usual active ABM conditions, the emotional content of cues is task-relevant and this may increase its salience. This salience side-effect may be relevant to ABM methods. While ACT remains a potentially important avenue for research and treatment, the current results provide a warning that undesirable side effects may occur. Future methods may be able to selectively train flexibility without inducing an increase in salience.

The specificity of temporal expectancy: Evidence from a variable foreperiod paradigm

In speeded choice tasks with variable foreperiods (FPs), individuals behaviourally adapt to various frequency manipulations. Adaptations have been shown to frequencies of different stimulus-response events, to frequencies of different foreperiods, and to frequencies of different event-foreperiod combinations. We have investigated how participants adapt to a situation where all three frequency manipulations are done simultaneously. Three variable foreperiod experiments are reported. In Experiment 1, one target (the peak distributed target) appeared particularly frequently after one particular FP (the peak foreperiod), while another target was less frequent and equally distributed over all foreperiods. In Experiment 2, the equally distributed target was overall more frequent than the peak distributed one. In both experiments, performance advantages for the peak distributed target were specific to the peak foreperiod, and performance advantages at the peak foreperiod were specific to the peak distributed targets. A third experiment showed that, when two differently frequent target are both equally distributed over FPs, the performance distribution over FPs is not significantly different between both targets. Together, the results suggest that participants were able to simultaneously and specifically adapt to frequency manipulations in events, foreperiods, and event-foreperiod combinations.

Response preparation with adjacent versus overlapped hands: A pupillometric study

Preparatory cues facilitate performance in speeded choice tasks. It is debated, however, whether the lateralized neuro-anatomical organization of the human motor system contributes to this facilitation. To investigate this issue, we examined response preparation in a finger-cuing task using two conditions. In the hands adjacent condition, the hands were placed adjacently to each other with index and middle fingers placed on four linearly arrayed response keys. In the overlapped hand placement condition, the fingers of different hands alternated, thus dissociating hand and spatial position factors. Preparatory cues specified a subset of two fingers. Left–right cues specified the two leftmost or two rightmost fingers. Inner–outer cues specified the two inner or outer fingers. Alternate cues specified the first and third, or the second and fourth finger in the response set. In addition to reaction time and response errors, we measured the pupillary response to assess the cognitive processing load associated with response preparation. Results showed stronger pupil dilations (and also longer RTs and more errors) for the overlapped than for the adjacent hand placement condition, reflecting an overall increase in cognitive processing load. Furthermore, the negative impact of overlapping the hands on pupil dilation interacted with cue type, indicating that left–right cues (associated with two fingers on one hand) suffered most from overlapping the hands. With the hands overlapped, alternate cues (now associated with two fingers on the same hand) produced the shortest RTs. These findings demonstrate the importance of motoric factors in response preparation.

Relation of Repetition Effect and Response Programming in a Speeded Choice Task

The present study tested the hypothesis that the repetition effect occurs during response programming. The choice reaction-time to initiate the second of two responses was examined when two consecutive responses were the same or different in their kinematics and force characteristics and repeated for two different stimuli. 12 subjects were required to react and produce the sequence of same or different force by squeezing a handle as quickly and accurately as possible after the first (auditory) and the second (visual) reaction signals. The response-stimulus interval was set at 500 msec. The choice reaction-time to initiate the second response was significantly shorter for the same-force condition than for the different-force and control conditions. This result indicates that the repetition effect originates in a speedup in response programming rather than response selection or perceptual identification. This finding was discussed in terms of bypassing a response-programming stage.

Procedural learning: I. Locus of practice effects in speeded choice tasks.

When subjects perform 750 trials of a speeded choice task mapping different categories of symbols (e.g., letters, digits) onto different responses, excellent transfer is observed to new items in the trained categories (Experiment 1). However, when arbitrary sets of stimuli are mapped onto each response, introducing new stimuli substantially retards performance (Experiment 2), even when the size of the potential stimulus set remains constant (Experiment 3). Surprisingly, responses to already trained items are as slow as responses to new items in these transfer tests. When the mapping is categorical, shuffling the assignment of stimuli to responses drastically slows responses (Experiment 4). However, changing to a spatially homologous mapping with responses on the other hand produces excellent transfer (Experiment 5). Together, these results indicate that practice in speeded choice tasks affects primarily the response selection stage, rather than perceptual processing or motor responses. These data suggest that practice primarily strengthens links between category representations and spatially defined responses. Furthermore, when an arbitrary collection of symbols is mapped onto a given response, practice produces an ad hoc category representation and strengthens links between individual items and the category, as well as links between the category and the response. With practice, people become dramatically faster and more accurate in sensorimotor skills. Characterizing these changes is of major importance, for both applied and theoretical purposes. In applied situations, it would be useful to know how conditions of skill acquisition can be structured so that learning is most efficient and to know when one form of training will produce useful transfer to other, related tasks. For theoretical purposes, understanding the functional character of skill learning should provide a basis for developing detailed models of the changes that underlie such learning (such as neural net models). The present article focuses on the changes in performance that occur with modest amounts of practice in very simple sensorimotor tasks, namely those requiring speeded choice responses. In speeded choice tasks, subjects are presented with a single stimulus and must rapidly select and execute a response depending on the identity of the stimulus. This is one of the simplest paradigms in which one can examine procedural skills and their development, and it provides a useful laboratory model for the numerous human skills that involve retrieving and producing arbitrary responses to stimuli. Performance in speeded choice tasks is subject to various kinds of change as subjects perform repeated trials. Subjects' responses become faster (and often more accurate)—the prac

Procedural learning: II. Intertrial repetition effects in speeded-choice tasks.

Previous research has demonstrated that subjects' responses in a speeded-choice task are affected by the sequence of stimuli and responses. Generally, responses are faster when the same stimulus is repeated. There is disagreement in the literature concerning whether or not this effect represents a speedup of perception, response execution, or central stages of processing. The first 5 experiments reported here demonstrate that the effect is quite stimulus specific: A succession of different stimuli that call for the same response produces little repetition benefit, unless the stimuli differ only in very superficial ways (e.g., in color). Increasing the intertrial interval from 100 ms to 1000 ms attenuates these repetition effects only slightly. These results would be consistent with a perceptual locus for the repetition effect, but Experiment 6 shows that if the response mapping changes from trial to trial, the advantage for stimulus repetitions is abolished The results indicate that locus of the repetition effect is at the stage of response selection. However, the stimulus specificity of the effects indicates that immediate repetitions produce or strengthen transient links that shortcut the response-selection stage. By contrast, the results of Pashler and Baylis (1991) indicate that practice primarily strengthens response selection at the categorical level rather than shortcutting it One implication of the results is that the practice effect is not created simply by the accumulation of the traces responsible for repetition effects.

Procedural learning: I. Locus of practice effects in speeded choice tasks.

Procedural learning: I. Locus of practice effects in speeded choice tasks.

Procedural learning: II. Intertrial repetition effects in speeded-choice tasks.

Procedural learning: II. Intertrial repetition effects in speeded-choice tasks.

Verbal Self-Reports as a Function of Speed, Accuracy, and Reinforcement of the Reported Performance

Undergraduates reported about their performance on a delayed matching-to-sample (DMTS) task in which monetary reinforcers depended on both speed and accuracy. They made the reports by pressing “Yes” or “No” buttons to answer computer- presented queries about the speed, accuracy, or reinforcement of their performance on the just-completed DMTS trial. Reports about accuracy were positively, but not strongly, correlated with actual performance. Reports about speed were consistently biased in favor of affirmative reports, with subjects reporting that their DMTS responses were fast enough to earn reinforcement, regardless of actual response speed. Reports about reinforcement showed substantial intersubject variability. Manipulating the interval between DMTS performance and the self-report (from 3 s to 27 s) had no systematic influence on the correspondence between reports and performance, regardless of whether a distractor task was required during the interval. These results are inconsistent with an hypothesis that individuals performing speeded choice tasks directly monitor both speed and accuracy. The experiment illustrates the viability of studying verbal self-reports as operant behavior under discriminative control of some, but possibly not all, aspects of the reported performance.