Dual route for subtask order control: Evidence from the psychological refractory paradigm

A change in subtask order in the psychological refractory period (PRP) paradigm increases the effect of stimulus onset asynchrony (SOA) on the second response. We used a paradigm with cued, randomly determined subtask order to test the hypothesis that this SOA by order switch overadditivity reflects order control, via “copying” stimulus order. In Experiments 1a and 1b, overadditivity was evident only with insufficient opportunity for cue-based order control. In Experiment 2, overadditivity was decreased by using the same set of stimuli in the two subtasks, presumably by removing the opportunity to rely on stimulus order. In Experiment 3, removing the order cue increased the overadditivity, presumably because control was based solely upon copying stimulus order. The results indicate interactive top-down and bottom-up order control. Implications to theories of the PRP paradigm are discussed.

Task Rule-Congruency and Simon-Like Effects in Switching between Spatial Tasks

In task switching, a response indicated as correct by both task rules is executed more quickly than one for which the rules disagree. This rule-congruency, so far demonstrated unequivocally only in nonspatial tasks, shows that the currently irrelevant task set is kept active. However, in spatial task-switching, rule-congruency could potentially reflect a preexperimental tendency that contributes to a Simon-like effect. In the present study, participants switched between RIGHT–LEFT and UP–DOWN tasks with either a standard key arrangement (e.g., upper key = UP) or a mapping-reversed arrangement (e.g., up = DOWN), which reverses the direction of the potential Simon-like effect but leaves potential rule-congruency effects unchanged. Mapping-reversal did not modulate any other effect, including rule-congruency, and therefore indicated rule-congruency unequivocally. Finally, implications concerning generality versus domain specificity of control processes in task switching are discussed.

Powerful Instructions: Automaticity Without Practice

Automaticity is widely assumed to reflect hardwired tendencies or the outcome of prior practice. Recent research on automatic effects of instruction (AEIs), however, indicates that newly instructed tasks can become immediately automatic without ever having been practiced. This research shows that the representations underlying AEIs need not always be directly linked to an overt response but must be highly accessible for future use and involve bidirectional links between stimuli and responses. AEIs were also found to decrease with increasing intellectual abilities among young adults and from childhood to young adulthood, possibly because of improved abstract cognitive control. We argue that AEIs are based on the unintentional retrieval of episodic memories that encode instructions.

The task novelty paradox: Flexible control of inflexible neural pathways during rapid instructed task learning

Rapid instructed task learning (RITL) is one of the most remarkable human abilities, when considered from both computational and evolutionary perspectives. A key feature of RITL is that it enables new goals to be immediately pursued (and shared) following formation of task representations. Although RITL is a form of cognitive control that engenders immense flexibility, it also seems to produce inflexible activation of action plans in inappropriate contexts. We argue that this "prepared reflex" effect arises because RITL is implemented in the brain via a "flexible hub" mechanism, in which top-down influences from the frontoparietal control network reroute pathways among procedure-implementing brain areas (e.g., perceptual and motor areas). Specifically, we suggest that RITL-based proactive control - the preparatory biasing of task-relevant functional network routes - results in inflexible associative processing, demanding compensation in the form of increased reactive (in-the-moment) control. Thus, RITL produces a computational trade-off, in which the top-down influences of flexible hubs increase overall cognitive flexibility, but at the cost of temporally localized inflexibility (the prepared reflex effect).

Examining procedural working memory processing in obsessive-compulsive disorder

Previous research has suggested that a deficit in working memory might underlie the difficulty of obsessive-compulsive disorder (OCD) patients to control their thoughts and actions. However, a recent meta-analyses found only small effect sizes for working memory deficits in OCD. Recently, a distinction has been made between declarative and procedural working memory. Working memory in OCD was tested mostly using declarative measurements. However, OCD symptoms typically concerns actions, making procedural working-memory more relevant. Here, we tested the operation of procedural working memory in OCD. Participants with OCD and healthy controls performed a battery of choice reaction tasks under high and low procedural working memory demands. Reaction-times (RT) were estimated using ex-Gaussian distribution fitting, revealing no group differences in the size of the RT distribution tail (i.e., τ parameter), known to be sensitive to procedural working memory manipulations. Group differences, unrelated to working memory manipulations, were found in the leading-edge of the RT distribution and analyzed using a two-stage evidence accumulation model. Modeling results suggested that perceptual difficulties might underlie the current group differences. In conclusion, our results suggest that procedural working-memory processing is most likely intact in OCD, and raise a novel, yet untested assumption regarding perceptual deficits in OCD.

Evidence for instructions-based updating of task-set representations: the informed fadeout effect

The cognitive system can be updated rapidly and efficiently to maximize performance in cognitive tasks. This paper used a task-switching task to explore updating at the level of the plausible task-sets held for future performance. Previous research suggested a "fadeout effect", performance improvement when moving from task-switching context to single-task context, yet this effect could reflect passive learning rather than intentional control. In a novel "informed fadeout paradigm", one of two tasks was canceled for a certain number of trials and participants were informed or uninformed regarding task cancelation. The "informed fadeout effect" indicates better performance in the informed than uninformed fadeout after one informed trial had been executed. However, the results regarding the first trial were inconclusive. Possible underlying mechanisms are discussed.

Automatic Retrieval of Newly Instructed Cue-Task Associations Seen in Task-Conflict Effects in the First Trial after Cue-Task Instructions

Abstract. Novel stimulus-response associations are retrieved automatically even without prior practice. Is this true for novel cue-task associations? The experiment involved miniblocks comprising three phases and task switching. In the INSTRUCTION phase, two new stimuli (or familiar cues) were arbitrarily assigned as cues for up-down/right-left tasks performed on placeholder locations. In the UNIVALENT phase, there was no task cue since placeholder’s location afforded one task but the placeholders were the stimuli that we assigned as task cues for the following BIVALENT phase (involving target locations affording both tasks). Thus, participants held the novel cue-task associations in memory while executing the UNIVALENT phase. Results show poorer performance in the first univalent trial when the placeholder was associated with the opposite task (incompatible) than when it was compatible, an effect that was numerically larger with newly instructed cues than with familiar cues. These results indicate automatic retrieval of newly instructed cue-task associations.

Can't take my eyes off of you: Tendency to maintain cognitive activation of significant other representations

Attachment is related to behaviors, including contact maintenance/proximity seeking, and to the keeping of the attachment figure physically, visually, or mentally accessible. In a series of experiments, we observed an analogous behavior in a simple laboratory task in the absence of any stress-related manipulations. Participants performed an easy, choice reaction time (RT) task (often emotionally neutral) on pictures (or names) of significant others versus other persons, both familiar and unfamiliar to them. Results showed that participants took longer to press the key, which started the next trial, when the current trial involved the picture (or name) of their significant other. This effect was observed among parents who responded to their children's pictures, people who are in a romantic relationship, and young adults who responded to the name of a parent; it was only eliminated when participants adopted an analytic approach (i.e., judged the person's age). These results indicate that attachment-related behavioral tendencies, associated with keeping the representation of the significant other active, may be easily invoked in a simple task, even without any apparent stress manipulation. (PsycINFO Database Record

Increased ongoing neural variability in ADHD

Attention Deficit Hyperactivity Disorder (ADHD) has been described as a disorder where frequent lapses of attention impair the ability of an individual to focus/attend in a sustained manner, thereby generating abnormally large intra-individual behavioral variability across trials. Indeed, increased reaction time (RT) variability is a fundamental behavioral characteristic of individuals with ADHD found across a large number of cognitive tasks. But what is the underlying neurophysiology that might generate such behavioral instability? Here, we examined trial-by-trial EEG response variability to visual and auditory stimuli while subjects' attention was diverted to an unrelated task at the fixation cross. Comparisons between adult ADHD and control participants revealed that neural response variability was significantly larger in the ADHD group as compared with the control group in both sensory modalities. Importantly, larger trial-by-trial variability in ADHD was apparent before and after stimulus presentation as well as in trials where the stimulus was omitted, suggesting that ongoing (rather than stimulus-evoked) neural activity is continuously more variable (noisier) in ADHD. While the patho-physiological mechanisms causing this increased neural variability remain unknown, they appear to act continuously rather than being tied to a specific sensory or cognitive process.

Exposure to salient, dynamic sensory stimuli during development increases distractibility in adulthood

It has been suggested that excessive exposure of children to the dynamic and highly salient audio-visual stimuli conveyed by electronic media may induce attention-related deficits in adulthood. This study was designed to evaluate this hypothesis in a controlled animal model setup. Building on their natural responsiveness to odors, we exposed juvenile rats for 1 h daily to a dynamic series of interchanging, highly salient odors, while controls were exposed to a non-changing mixture of these odors. Upon reaching adulthood, we tested the attentional capacity of the rats and measured their brain-derived neurotrophic factor (BDNF) levels as a proxy of neuronal plasticity. As compared with controls, rats exposed to the dynamic stimulation showed no attentional deficits under baseline task conditions, but their performance was dramatically impaired when an auditory distractor was introduced in the task. In addition, BDNF levels in the dorsal striatum of these rats were significantly increased relative to controls. These findings provide first empirical evidence that a continuous exposure to dynamic, highly salient stimuli has long-term effects on attentional functions later in life, and that these effects may have neural correlates in the dorsal striatum.

Memory for Action Rules and Reaction Time Variability in Attention-Deficit/Hyperactivity Disorder

BACKGROUND

Patients with attention-deficit/hyperactivity disorder (ADHD) exhibit increased reaction time (RT) variability. This finding is consistent across various choice RT tasks and is considered a core ADHD phenotype, often interpreted as expressing occasional attention lapses. This study explores the selective contribution of perceptual and working memory (WM) processes to increased RT variability in ADHD.

METHODS

Low and high WM demands were manipulated in a battery of choice RT tasks administered to two groups of college students (subjects with ADHD vs. healthy control subjects).

RESULTS

Ex-Gaussian distribution fitting revealed an increased rate of exceptionally slow RTs (i.e., higher τ values) in subjects with ADHD under all conditions. These group differences interacted with WM demands, showing the largest group differences when WM processing was most demanding (η_p² = .32). Under demanding WM conditions, evidence accumulation modeling demonstrated that increased RT variability in ADHD is not associated with either momentary or constant deficits in perceptual processing of the target. Rather, results favored a model associating increased RT variability in ADHD with reduced rate of WM retrieval.

CONCLUSIONS

These results suggest a pivotal contribution for the retrieval of action rules from WM to increased RT variability in ADHD.

Go with the flow: how the consideration of joy versus pride influences automaticity

Recently, we have shown that the consideration of joy, without the actual experience of the emotion, impaired performance on the antisaccade task (Katzir, Eyal, Meiran, & Kessler, 2010). We interpreted this finding as indicating inhibitory control failure. However, impaired antisaccade performance may result from either the weakening of inhibitory control, the potentiation of the competing automatic response, or both. In the current research we used a task switching paradigm, which allowed us to assess cognitive control more directly, using Backward Inhibition, Competitor Rule Suppression, and Competitor Rule Priming as cognitive-control indices as well as assessing the Task Rule Congruency Effect (TRCE) which, like the antisaccade, is influenced by both control and automaticity. We found that considering joy compared to pride did not influence any of the cognitive control indices but increased the TRCE. We interpret this finding as evidence that joy consideration leads to increased reliance on automatic tendencies, such as short-term desires.

The power of instructions: Proactive configuration of stimulus-response translation

Humans are characterized by an especially highly developed ability to use instructions to prepare toward upcoming events; yet, it is unclear just how powerful instructions can be. Although prior work provides evidence that instructions can be sufficiently powerful to proactively program working memory to execute stimulus-response (S-R) translations, in a reflexlike fashion (intention-based reflexivity [IBR]), the results to date have been equivocal. To overcome this shortcoming, we developed, and tested in 4 studies, a novel paradigm (the NEXT paradigm) that isolates IBR effects even prior to first task execution. In each miniblock, participants received S-R mapping instructions for a new task. Prior to implementing this mapping, responses were required to advance through screens during a preparatory (NEXT) phase. When the NEXT response was incompatible with the instructed S-R mapping, interference (IBR effect) was observed. This NEXT compatibility effect and performance in the implementation (GO) trials barely changed when prior practice of a few trials was provided. Finally, a manipulation that encouraged preparation resulted in relatively durable NEXT compatibility effects (indicating durable preparatory efforts) coupled with improved GO performance (indicating the success of these efforts). Together, these findings establish IBR as a marker of instructed proactive control.

Post-error slowing is influenced by cognitive control demand

Post-error slowing (PES) has been shown to reflect a control failure due to automatic attentional capture by the error. Here we aimed to assess whether PES also involves an increase in cognitive control. Using a cued-task-switching paradigm (Experiment 1) and a Stroop task (Experiment 2), the demand for top down control was manipulated. In Experiment 1, one group received dimension cues indicating the relevant stimulus dimension (e.g., "number") without specifying the response-category-to-key mapping, hence requiring considerable top down control. Another group was shown mapping cues providing information regarding both the relevant task identity and its category-to-key mapping (e.g., "one three"), requiring less top down control, and the last group received both types of cues, intermixed. In Experiment 2, one group performed a pure incongruent Stroop condition (name ink color of incongruent color names, high control demand), and another group received a pure neutral Stroop condition (name color patches, low control demand). In Experiment 2a, participants received the two conditions, intermixed. A larger PES was observed with dimension cues as compared with mapping cues, and with incongruent Stroop stimuli as compared to neutral stimuli, but not when the conditions were intermixed. These findings reveal that PES is influenced by the control demands that characterize the given block-wide experimental context and show that proactive cognitive control is involved in PES.

Selective influence of working memory load on exceptionally slow reaction times

The rate of exceptionally slow reaction times (RTs), described by the long tail of the RT distribution, was found to be amplified in a variety of special populations with cognitive deficits (e.g., early-stage Alzheimer's disease, attention-deficit/hyperactivity disorder, low intelligence, elderly). Previous individual differences studies found high correlations between working memory (WM) and parameters that characterize the magnitude of the long-RT tail. However, the causal direction remains unknown. In 3 choice-reaction task experiments, we examined this relationship by directly manipulating WM availability. In Experiment 1, the stimulus-response rules were either arbitrary (WM demanding) or nonarbitrary. In Experiment 2, the arbitrary rules were either novel (demanding) or practiced. In Experiment 3, WM was loaded with either declarative (stimulus-stimulus) or procedural (stimulus-response) arbitrary rules. Using an ex-Gaussian model fitting, we found across all experiments that WM demands uniquely influenced the τ parameter, mostly responsible for the long-RT distribution tail. Evidence accumulation modeling of the choice process indicated that WM load had little influence on the decision process itself and primarily affected the duration of an exponentially distributed nondecision component, assumed to reflect the process of rule retrieval. Theoretical interpretations and implications are discussed.

Differential contribution of task conflicts to task switch cost and task mixing cost in alternating runs and cued task-switching: evidence from ex-Gaussian modeling of reaction time distributions

Task switching involves switch cost (poorer performance switch trials than in task-repetition trials) and mixing cost (poorer performance in task-repetition trials than in trials from blocks without task switching). These are mainly studied with the alternating runs task-switching (ARTS) paradigm (in which the task changes every constant number of trials) or the cued task-switching (CTS) paradigm, in which the tasks change randomly. The authors tested the hypothesis that dealing with actual or potential conflicts regarding which task is currently required contribute to mixing cost in CTS more than in ARTS and contribute to switch costs more in ARTS than in CTS. This hypothesis was tested using ex-Gaussian modeling of reaction time (RT) distributions, in which the heaviness of the right tail marks task conflicts (Steinhauser and Hübner in J Exp Psychol Human Percept Perform 35:1398-1412 2009). As predicted, a heavier RT-distribution tail marked switch cost more strongly in ARTS than in CTS and marked mixing costs more strongly in CTS than in ARTS. These results indicate that switch cost and mixing cost reflect different processes in different task-switching paradigms.

The role of emotional engagement and mood valence in retrieval fluency of mood incongruent autobiographical memory

Background: Retrieval of opposite mood autobiographical memories serves emotion regulation, yet the factors influencing this ability are poorly understood.

Methods: Three studies examined the effect of mood valence (sad vs. happy) and degree of emotional engagement on fluency of mood incongruent retrieval by manipulating emotional engagement and examining the effect of emotional film clips on the Fluency of Autobiographical Memory task.

Results: Following both sad and happy film clips, participants who received emotionally engaging instructions exhibited a greater recall latency of the first opposite mood memory, and had generated less such memories than those receiving emotionally disengaging instructions (Studies 1 and 2). A happy mood induction resulted in recollection of fewer mood incongruent memories compared to a sad mood induction. Providing emotionally engaging instructions was found to specifically hinder mood incongruent retrieval, without impairing mood congruent retrieval (Study 3).

Conclusion: High emotional engagement seems to impair the retrieval of mood incongruent memories. Being in a happy mood may also partially impair such retrieval. Implications regarding emotional regulation are discussed.