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Cognitive flexibility enables humans to voluntarily switch tasks. Task switching requires replacing the previously active task representation with a new one, an operation that typically results in a switch cost. Thus, understanding cognitive flexibility requires understanding how tasks are represented in the brain. We hypothesize that task representations are cognitive map-like, such that the magnitude of the difference between task representations reflects their conceptual differences: The greater the distinction between the two task representations, the more updating is required. This hypothesis predicts that switch costs should increase with between task dissimilarity. To test this hypothesis, we use an experimental design that parametrically manipulates the similarity between task rules. We observe that response time scales with the dissimilarity between the task rules. The findings shed light on the organizational principles of task representations and extend the conventional binary task-switch effect (task repeat vs. switch) to a theoretical framework with parametric task switches. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

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How are visual sensory representations that are acquired peripherally from a saccade target related to sensory representations generated foveally after the saccade? We tested the hypothesis that, when the two representations are perceived to belong to the same object, the post-saccadic value tends to overwrite the pre-saccadic value. Participants executed a saccade to a colored target object, which sometimes changed during the saccade by ±15°, 30°, or 45° in color space. They were post-cued to report either the pre-saccadic or post-saccadic color in a continuous report procedure. Substantial overwriting of the pre-saccadic color by the post-saccadic color was observed. Moreover, the introduction of a brief post-saccadic blank interval (which disrupted the perception of object correspondence) led to a substantial reduction in overwriting. The results provide the first direct evidence for an object-mediated overwriting mechanism across saccades, in which post-saccadic values automatically replace pre-saccadic values.

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The early work of Charles W. Eriksen and colleagues provided us with both the flanker task and the concepts of response competition and continuous flow. The model of the flanker task that Eriksen and colleagues developed also includes the idea that processing occurs in two phases and the specific claim that pro-active response inhibition is employed to prevent errors under certain conditions. We first replicated and extended the behavioral evidence that motivated this specific claim and then tested it using a variety of physiological measures. We verified the prediction of Eriksen's Two-Phase Model of Spatial Selective Attention using the lateralized readiness potential and contingent negative variation. We also clarified a detail of the model using electromyographic activity and response force. We note that this contribution of Charles W. Eriksen has not received the attention that it deserves and that several recent models might need to be revised in light of Eriksen's work.

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When responding to the identity of a visual target, nearby stimuli (flankers) that are associated with the same response as the target cause faster and more accurate responding than flankers that are associated with different responses. Because this flanker-congruence effect (FCE) decreases with increasing target-flanker separation, it was thought to reflect limited precision of spatial selection mechanisms. Later studies, however, showed that FCEs are larger when the target and flankers are the same color compared to when they are different colors. This led to the group selection hypothesis, which states that flankers are perceptually grouped with the target and are obligatorily selected along with it, regardless of spatial separation. An alternative hypothesis, the image segmentation hypothesis, states that feature differences facilitate the segmentation of visual information into relevant and irrelevant parts, thereby mitigating the limitations of spatial precision of selection mechanisms. We test between these hypotheses using a design in which targets and flankers are grouped or not grouped, while holding feature differences in the stimulus constant. Contrary to earlier results, we found that same-colored flankers do not yield larger FCEs than different-colored flankers when feature differences are held constant. We conclude that similarity effects on the FCE reflect differential support for image segmentation, on which selection depends, rather than the obligatory selection of perceptually grouped flankers and targets.

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Irrelevant aspects of the environment or irrelevant attributes of task-relevant stimuli can have important and reliable effects on behavior. When the specific values of an irrelevant attribute are correlated with different responses, a correlational-cuing effect is observed: faster and more accurate responses when the correlation is positive. Previous work has shown that this effect is not due to simple differences in how often the specific stimuli or attributes are being presented, and most explanations of the effect have stressed the clear parallels with classical associative learning. There are alternative explanations, however, that center on instances, episodes, or events, instead of associative learning. One such model posits that transient bindings between irrelevant stimulus attributes and responses (i.e., most-recent-pairings) may be responsible for the correlation-cuing effect and some recent work has found no evidence of correlational cuing when most-recent-pairings are taken into account. However, the experimental conditions that were employed previously may not have been optimized for associative learning. A new experiment that was designed to emphasize associative learning was conducted and produced reliable evidence of correlational cuing even when controlling for most-recent-pairing effects.

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Theories of working memory (WM) differ in their claims about the number of items that can be maintained in a state that directly interacts with other, ongoing cognitive operations (termed the focus of attention). A similar debate has arisen in the literature on visual working memory (VWM), focused on the number of items that can simultaneously interact with attentional priority. In 3 experiments, we used a redundancy-gain paradigm to provide a comprehensive test of the latter question. Participants searched for 2 cued features (e.g., a color and a shape) within a search array. The cued feature values changed on a trial-by-trial basis, requiring VWM. The target (when present) could match 1 of the cued features (single-target trials) or both cued features (redundant-target trials). We tested whether response time distributions contained a substantial proportion of trials with redundant-target responses that were faster than predicted by 2 independent guidance processes operating in parallel (i.e., violations of the race-model inequality). Violations are consistent with a coactive architecture in which both cued values guide attention in parallel and sum on the priority map. Robust violations were observed in all cases predicted by the hypothesis that multiple items in VWM can guide attention simultaneously, and these results were inconsistent with the hypothesis that guidance is limited to a single item simultaneously. When considered in the larger context of the literature on VWM and attention, the present results are consistent with a model of WM architecture in which the focus of attention can maintain multiple, independent representations. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

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In Mordkoff (2017), the intention was to exclude from the analyses all trials that immediately followed an error.

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Hick/Hyman Law is the linear relationship between average uncertainty and mean response time across entire blocks of trials. While unequal trial-type frequencies within blocks can be used to manipulate average uncertainty, the current version of the law does not apply to or account for the differences in mean response time across the different trial types contained in a block. Other simple predictors of the effects of trial-type frequency also fail to produce satisfactory fits. In an attempt to resolve this limitation, the present work takes a hierarchical approach, first fitting the block-level data using average uncertainty (i.e., Hick/Hyman Law is given priority), then fitting the remaining trial-level differences using various versions of trial-type frequency. The model that employed the relative probability of occurrence as the second-layer predictor produced very strong fits, thereby extending Hick/Hyman Law to the level of trial types within blocks. The advantages and implications of this hierarchical model are briefly discussed.

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A dominant account of selective attention, perceptual load theory, proposes that when attentional resources are exhausted, task-irrelevant information receives little attention and goes unrecognized. However, the flanker effect-typically used to assay stimulus identification-requires an arbitrary mapping between a stimulus and a response. We looked for failures of flanker identification by using a more-sensitive measure that does not require arbitrary stimulus-response mappings: the correlated flankers effect. We found that flanking items that were task-irrelevant but that correlated with target identity produced a correlated flanker effect. Participants were faster on trials in which the irrelevant flanker had previously correlated with the target than when it did not. Of importance, this correlated flanker effect appeared regardless of perceptual load, occurring even in high-load displays that should have abolished flanker identification. Findings from a standard flanker task replicated the basic perceptual load effect, with flankers not affecting response times under high perceptual load. Our results indicate that task-irrelevant information can be processed to a high level (identification), even under high perceptual load. This challenges a strong account of high perceptual load effects that hypothesizes complete failures of stimulus identification under high perceptual load. (PsycINFO Database Record

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The magnitude of congruency effects depends on, among other things, the specifics of previous trials. To explain these modulating effects, a host of mechanisms by which previous trials affect the processing of relevant and irrelevant information on the present trial have been proposed, including feature repetition advantages, negative priming, item-specific proportion congruency (ISPC) effects, display frequency effects, and sequential modulations of both congruency and frequency effects. However, few experiments have been designed to independently manipulate these factors. In the present study, we used a four-choice Stroop task in which we hold constant the frequencies of the stimulus features and responses, but manipulate the frequencies of their conjunctions. We modified the procedure used by Jacoby et al. (2003), under which the possible word-color pairings differed in terms of proportion occurrence, by adding neutral trials to obtain independent estimates of the effects of display frequency. The results indicate that feature repetitions, display frequency, and sequential modulations of both congruency and frequency effects all affect response time. However, no evidence for an ISPC effect was obtained; the display frequency effect measured on the neutral trials accounted for all differences in the congruency effect, as proposed by Schmidt and Besner (2008). Sequential modulations of congruency effects were observed when the overall proportion of congruent trials was held to a chance level and marginal display frequency was also held constant.

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Awakening from different sleep stages, percentage of different stages of sleep subsumed within a sleep episode, and sleep episode length, have all been hypothesized to affect cognitive performance upon awakening. To further examine the contribution of these factors, 14 healthy participants slept for 3 h (0300-0600 hours) and 6 h (2400-0600 hours), with each sleep episode separated by 1 week. Electroencephalographic measures were taken throughout each sleep episode, and participants completed the Attentional Network Test, which measures alerting, orienting, and executive functioning (conflict) components of attention, upon awakening. Overall, mean reaction time (RT) was slower in the 3- and 6-h post-sleep conditions than in a baseline (pre-sleep) condition. Alerting, orienting, and conflict measures of attention did not significantly differ across the baseline and two post-sleep conditions. Awakening from REM sleep resulted in slower overall RT than awakening from lighter sleep (stages 1 and 2). In multiple regression analyses, overall RT was predicted by the duration of slow wave sleep (SWS), such that more time spent in SWS was associated with an overall slowing of RT. Conflict scores were predicted by the duration of REM; that is, more time spent in REM was associated with greater amounts of conflict (i.e., larger flanker effects). These data provide more information about the process of awakening and suggest that SWS and REM influence different aspects of attention upon awakening.

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Sequential modulation is the finding that the sizes of several selective-attention phenomena--namely, the Simon, flanker, and Stroop effects--are larger following congruent trials than following incongruent trials. In order to rule out relatively uninteresting explanations of sequential modulation that are based on a variety of stimulus- and response-repetition confounds, a four-alternative forced choice task must be used, such that all trials with any kind of repetition can be omitted from the analysis. When a four-alternative task is used, the question arises as to whether to have the proportions of congruent and incongruent trials be set by chance (and, therefore, be 25% congruent and 75% incongruent) or to raise the proportion of congruent trials to 50%, so that it matches the proportion of incongruent trials. In this observation, it is argued that raising the proportion of congruent trials to 50% should not be done. For theoretical, practical, and empirical reasons, having half of the trials be congruent in a four-alternative task aimed at providing unambiguous evidence of sequential modulation should be avoided.

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Salient but irrelevant stimuli seem to cause an automatic orienting of covert attention, facilitating the detection of targets at the cued location for a brief period of time. However, this finding is highly dependent on the number of possible target locations, at least when the simple detection of targets is all that the task requires. Whereas small numbers of possible target locations (e.g., 2 or 3) produce the well-known advantage in response time for valid cue trials (i.e., a positive cuing effect), larger numbers of possible target locations (e.g., 6 or 8) produce a negative cuing effect. If not explained in terms of a nonattentional mechanism, this latter finding raises serious questions about the standard interpretation of positive cuing effects. The present experiment tested a particular nonattentional mechanism: that a confound between target presence and apparent motion, which occurs only on invalid cue trials, is responsible for negative cuing effect. We reduced or eliminated this confound by the use of a new type of catch trial and eliminated the negative cuing effect with large numbers of target locations.

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The logic of the Subtraction Method is used implicitly or explicitly in a variety of work, ranging from traditional response-time research to functional neuroimaging. One assumption of all forms of the Subtraction Method is that components may be inserted (or deleted) without causing changes in the remaining components. We tested this assumption as it applies to the duration of late motor processing using the lag between the onset of lateralized readiness potential (LRP) and the production of the required response as the measure of late motor processing. In contrast to a similar, previous study that used this approach (Miller & Low, 2001), we found differences in the LRP lags across the types of task that are used in the Subtraction Method. The LRP lag for simple-RT was shorter than the lags for either go/no-go or choice-RT. This finding constitutes evidence against an assumption required by the Subtraction Method, at least as applied to component durations, but can be explained in terms of a supplementary (non-subtractive) inhibitory component that is only employed in the go/no-go task.

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When a single perceptual object provides two different reasons for a particular decision (by containing two qualitatively different targets), detailed analyses of the response-time distributions have shown that the two different reasons are jointly responsible for the final decision. The question is whether this coactivation occurs because the two targets contained by the object were from separate dimensions (e.g., color and shape) or were parts of the same perceptual object. Early work argued in favor of dimensions, implying that the types of information being processed is critical, as opposed to their sources; more recent work has argued in favor of objects. Experiment 1 in the present paper corrected for a potential bias in the design of some recent studies and found additional evidence in favor of objects. Two additional experiments directly manipulated whether redundant targets would be perceived as parts of one or two perceptual objects (while holding all else constant) and produced the strongest evidence to date that coactivation requires that the redundant targets be parts of one object. This reverses the original conclusion and suggests that the sources of information are critical, as opposed to the types. Two specific versions of the object-based model are discussed.

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The effects of spatial compatibility and spatial congruence have both been explained in terms of a dual-route model under which spatial information about the stimulus, regardless of task relevance, is directly passed from perception to action. Recently, however, some alternatives to the dual-route model of the Simon Effect have been proposed (or re-introduced) as viable explanations. The present experiment compared the magnitudes of the effects of spatial compatibility and spatial congruence across a range of tasks that varied in their dimensional overlap. The results exhibited a remarkable parallel between the two phenomena when viewed only in terms of the interaction between stimulus set and response set. This could be taken as new evidence for a common origin. However, when the entire pattern of results was examined, a large difference between compatibility and congruence were also seen, which implies that there is at least one important difference between the two phenomena.

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The present study examined performance across three two-choice tasks that used the same two stimuli, the same two stimulus locations, and the same two responses to determine how task demands can alter the Simon Effect, its distribution across reaction time, and its sequential modulation. In two of the tasks, repetitions of stimulus features were not confounded with sequences of congruent and incongruent trials. This attribute allowed us to investigate the sequential modulation of the Simon Effect in a two-choice task while equalizing the occurrence of feature repetitions. All tasks showed a similar sequential modulation, suggesting that it is not driven by feature repetitions. Moreover, distributional analyses revealed that the advantage for congruent trials decreased as reaction time increased similarly following congruent and incongruent trials. Finally, a large increase in RT was observed when repeated responses were made to novel stimuli and when novel responses were made to repeated stimuli. This effect also showed a sequential modulation regardless of whether the stimulus repeated. The findings suggest that, even in two-choice tasks, response selection is mediated by complex, dynamic representations that encode abstract properties of the task rather than just simple features.

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Bilateral interference, referring to the tendency of movements of one arm to disrupt the intended movements made simultaneously with the other arm, is often observed in a task that involves differential planning of each arm movement during sensorimotor adaptation. In the present study, we examined two questions: 1) how does the compatibility between visuomotor adaptation tasks performed with both arms affect bilateral interference during bimanual performance? and 2) how do variations in bilateral interference affect transfer of visuomotor adaptation between bilateral and unilateral conditions? To examine these questions, we manipulated visuomotor compatibility using two kinematic variables (direction of required hand motion, direction of an imposed visual rotation). Experiment 1 consisted of two conditions in which the direction of visual rotations for both arms was either in the same or opposing directions, whereas the target direction for both arms was always the same. In experiment 2, we examined the pattern of generalization between the bilateral and unilateral conditions when both the target and rotation directions were opposing between the arms. In both experiments, subjects first adapted to a 30° visual rotation with one arm (preunilateral), then with both arms (bilateral), and finally with the arm that was not used in the first session (postunilateral). Our results show that bilateral interference was smallest when both variables were the same between the arms. Our data also show extensive transfer of visuomotor adaptation between bilateral and unilateral conditions, regardless of degree of bilateral interference.

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Recent research on attention has identified three separable components, known as alerting, orienting, and executive functioning, which are thought to be subserved by distinct neural networks. Despite systematic investigation into their relatedness to each other and to psychopathology, little is known about how these three networks might be modulated by such factors as time-of-day and chronotype. The present study administered the Attentional Network Test (ANT) and a self-report measure of alertness to 80 participants at 0800, 1200, 1600, and 2000 hours on the same day. Participants were also chronotyped with a morningness/eveningness questionnaire and divided into evening versus morning/neither-type groups; morning chronotypes tend to perform better early in the day, while evening chronotypes show enhanced performance later in the day. The results replicated the lack of any correlations between alerting, orienting, and executive functioning, supporting the independence of these three networks. There was an effect of time-of-day on executive functioning with higher conflict scores at 1200 and 1600 hours for both chronotypes. The efficiency of the orienting system did not change as a function of time-of-day or chronotype. The alerting measure, however, showed an interaction between time-of-day and chronotype such that alerting scores increased only for the morning/neither-type participants in the latter half of the day. There was also an interaction between time-of-day and chronotype for self-reported alertness, such that it increased during the first half of the day for all participants, but then decreased for morning/neither types (only) toward evening. This is the first report to examine changes in the trinity of attentional networks measured by the ANT throughout a normal day in a large group of normal participants, and it encourages more integration between chronobiology and cognitive neuroscience for both theoretical and practical reasons.

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