Proactive response preparation contributes to contingency learning: novel evidence from force-sensitive keyboards.

Contingency learning can involve learning that the identity of one stimulus in a sequence predicts the identity of the next stimulus. It remains unclear, however, whether such learning speeds responses to the next stimulus only by reducing the threshold for triggering the expected response after stimulus onset or also by preparing the expected response before stimulus onset. To distinguish between these competing accounts, we manipulated the probabilities with which each of two prime arrows (Left and Right) were followed by each of two probe arrows (Up and Down) in a prime-probe task while using force-sensitive keyboards to monitor sub-threshold finger force. Consistent with the response preparation account, two experiments revealed greater force just before probe onset on the response key corresponding to the direction in which the probe was more (versus less) likely to point (e.g., Up vs. Down). Furthermore, mirroring sequential contingency effects in behavior, this pre-probe force effect vanished after a single low-probability trial. These findings favor the response preparation account over the threshold only account. They also suggest the possibility that contingency learning in our tasks indexes trial-by-trial expectations regarding the utility of the prime for predicting the upcoming probe.

Is conflict adaptation adaptive? An introduction to conflict monitoring theory and the ecological problems it faces.

Attending to a single stimulus (or dimension of a stimulus) requires filtering out distracting stimuli to avoid producing an incorrect response. The conflict monitoring (or conflict adaptation) account proposes that experience of conflict results in a shift of attention away from distracting stimuli and/or towards the target stimulus. The proportion congruent and congruency sequence effects are two findings often used to argue in favour of the conflict monitoring account. However, there are several potential limitations with conflict monitoring theory. This article explores some of the previously unarticulated (or rarely articulated) supplementary assumptions that must be made for the conflict monitoring account to be consistent with several important findings in the literature, some of which might undermine the initial intuitive appeal of the theory. Indeed, this opinion paper presents the view that conflict adaptation may not actually be particularly adaptive for performance. This article also discusses alternative interpretations of so-called "attentional control" phenomena. According to this view, participants may simply be learning regularities in the task structure that are unintentionally introduced when manipulating conflict (e.g., contingent regularities between distracting stimuli and responses). This sort of learning does benefit performance and is inherent for our functioning in the world, making this a more parsimonious view. Although simplicity is not everything, this article will present the case that the assumptions (often hidden or non-obvious) of conflict monitoring theory are non-trivial and, in many cases, imply relatively non-adaptive processes.

Incidental learning in music reading: The music contingency learning task.

The present report investigated whether nonmusicians can incidentally learn musical skills needed for sight-reading. On each trial, participants identified a note name written inside of a note on the musical staff. In Experiment 1, each note was presented frequently with the congruent note name (e.g., "do" with the note for "do") and rarely with the incongruent names (e.g., "do" with the note for "fa"). With or without deliberate learning instructions, a robust contingency learning effect was observed: faster responses for congruent trials compared with incongruent trials. Participants also explicitly identified the meaning of the note positions more accurately than chance. Experiment 2 ruled out the potential influence of preexisting knowledge on the contingency learning effect by presenting notes most often with an incongruent note name. Robust learning was again observed, suggesting that participants acquired sufficient knowledge of musical notation to produce automatic influences on behaviour (e.g., akin to the interference effect previously found in skilled musicians). A congruency effect was additionally observed in Experiment 2, however. Experiment 3 further explored to what extent this congruency effect might be due to prior music knowledge and/or spatial stimulus-response compatibility between note and response locations (analogous to the SMARC effect). Overall, our results open up new avenues for investigating the incidental learning of complex material, musical or otherwise, and for reinforcing learning even further.

Interlinguistic conflict: Word-word Stroop with first and second language colour words.

The congruency (or Stroop) effect is a standard observation of slower and less accurate colour identification to incongruent trials (e.g. "red" in green) relative to congruent trials (e.g. "red" in red). This effect has been observed in a word-word variant of the task, when both the distracter (e.g. "red") and target (e.g. "green") are colour words. The Stroop task has also been used to study the congruency effect between two languages in bilinguals. The typical finding is that the congruency effect for L1 words is larger than that for L2 words. For the first time, the present report aims to extend this finding to a word-word variant of the bilingual Stroop task. In two experiments, French monolinguals performed a bilingual word-word Stroop task in which target word language, language match, and congruency between the distracter and target were manipulated. The critical manipulation across two experiments concerned the target language. In Experiment 1, target language was manipulated between groups, with either French (L1) or English (L2) target colour words. In Experiment 2, target words from both languages were intermixed. In both experiments, the congruency effect was larger when the distracter and target were from the same language (language match) than when they were from different languages (language mismatch). Our findings suggested that this congruency effect mostly depends on the language match between the distracter and target, rather than on a target language. It also did not seem to matter whether the language-mismatching distracter was or was not a potential response alternative. Semantic activation of languages in bilinguals and its implications on target identification are discussed.

Stimulus and response conflict from a second language: Stroop interference in weakly-bilingual and recently-trained languages.

The aim of the present manuscript was to investigate the source of congruency effects in weak bilinguals (Experiment 1) and in early language learning (Experiment 2). In both studies, participants performed a bilingual version of a colour-word Stroop task. The standard finding is slower and less accurate responding when the word and colour are incongruent (e.g., "red" in blue) relative to congruent (e.g., "red" in red). This congruency effect occurs for the distracting colour words from both the first and second language. Both stimulus conflict (i.e., conflict between the meaning of the word and ink colour) and response conflict (i.e., conflict between possible response options) contribute to first-language congruency effects. According to some models of early language learning, only one of these two types of conflict should emerge for non-fluent languages. To separate stimulus and response conflict, we used a 2-to-1 keypress assignment manipulation. Interestingly, in one study both stimulus and response conflict were evidenced for the weakly spoken second language (English in native French speakers). In a second study, participants performed a short Croatian colour word learning phase before the Stroop procedure. Stimulus conflict was observed in response times and response conflict in errors for this recently-trained language. These findings suggest that the relatively low-proficient second language words are potent enough to affect semantic identification and response selection.

An Episodic Model of Task Switching Effects: Erasing the Homunculus from Memory.

The Parallel Episodic Processing (PEP) model is a neural network for simulating human performance in speeded response time tasks. It learns with an exemplar-based memory store and it is capable of modelling findings from various subdomains of cognition. In this paper, we show how the PEP model can be designed to follow instructions (e.g., task rules and goals). The extended PEP model is then used to simulate a number of key findings from the task switching domain. These include the switch cost, task-rule congruency effects, response repetition asymmetries, cue repetition benefits, and the full pattern of means from a recent feature integration decomposition of cued task switching (Schmidt & Liefooghe, 2016). We demonstrate that the PEP model fits the participant data well, that the model does not possess the flexibility to match any pattern of results, and that a number of competing task switching models fail to account for key observations that the PEP model produces naturally. Given the parsimony and unique explanatory power of the episodic account presented here, our results suggest that feature-integration biases have a far greater power in explaining task-switching performance than previously assumed.

Erasing the Homunculus as an Ongoing Mission: A Reply to the Commentaries.

In our recent article (Schmidt, Liefooghe, & De Houwer, 2020, this volume), we presented an adaptation of the Parallel Episodic Processing (PEP) model for simulating instruction following and task-switching behaviour. In this paper, we respond to five commentaries on our article: Monsell & McLaren (2020), Koch & Lavric (2020), Meiran (2020), Longman (2020), and Pfeuffer (2020). The commentaries discuss potential future modelling goals, deeper reflections on cognitive control, and some potential challenges for our theoretical perspective and associated model. We focus primarily on the latter. In particular, we clarify that we (a) acknowledge the role of cognitive control in task switching, and (b) are arguing that certain task-switching effects do not serve as a good measure of said cognitive control. We also discuss some ambiguities in terminological uses (e.g., the meaning of "task-set reconfiguration"), along with some future experimental and modelling research directions.

Contingency learning as binding? Testing an exemplar view of the colour-word contingency learning effect.

The learning of contingent regularities between events is fundamental for interacting with our world. We are also heavily influenced by recent experiences, as frequently studied in the stimulus-response binding literature. According to one view ("unitary view"), the learning of regularities across many events and the influence of recent events on current performance can coherently be explained with one high-learning rate memory mechanism. That is, contingency learning effects and binding effects are essentially the same thing, only studied at different timescales. On the other hand, there may be more to a contingency effect than just the summation of the influence of past events (e.g., an additional impact of learned regularities). To test these possibilities, the current report reanalyses a number of datasets from the colour-word contingency learning paradigm. It is shown that the weighted sum of binding effects accumulated across many previous trials (with especially strong influence of very recent events) does explain a large chunk of the contingency effect, but not all of it. In particular, the asymptote towards which the contingency effect decreases by accounting for an increasing number of previous-trial binding effects is robustly above zero. On the other hand, we also observe evidence for higher-order interactions between binding effects at differing lags, suggesting that a mere linear accumulation of binding episodes might underestimate their influence on contingency learning. Accordingly, focusing only on episodic stimulus-response binding effects that are due to the last occurrence of a stimulus rendered contingency learning effects non-significant. Implications for memory models are discussed.

Stroop-like effects of derived stimulus-stimulus relations.

Automaticity can be established by consistently reinforcing contingencies during practice. During reinforcement learning, however, new relations can also be derived, which were never directly reinforced. For instance, reinforcing the overlapping contingencies A → B and A → C, can lead to a new relation B-C, which was never directly reinforced. Across 5 experiments we investigated if such derived relations can also induce automatic effects. We first trained participants to derive a relation between a nonsense word and a color word, and then used the nonsense words as distractors in a Stroop task. Results indicate that derived color-word associates induce Stroop effects. This effect, however, is present only when sufficient attention is allocated to the distractor words during the Stroop task, and is driven by a response conflict. We conclude that, under the present training conditions, derived color-word associates became related to the corresponding color word at the lexical level, but did not gain direct access to the corresponding semantic color representation. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

The Use of Coffee to Decrease the Incidence of Postoperative Ileus: A Systematic Review and Meta-Analysis.

PURPOSE: To investigate the efficacy of providing coffee to elective abdominal surgery patients, immediately postoperatively, to lessen postoperative ileus. DESIGN: A systematic review with meta-analysis of six randomized controlled trials published since 2012. METHODS: Methodological quality was evaluated using the Cochrane guidelines. The Grading of Recommendations, Assessment, Development, and Evaluations assessment tool evaluated the quality of the evidence. Subgroup analyses were completed if the I2 statistic demonstrated heterogeneity (greater than 50%). FINDINGS: Coffee was statistically significant in shortening the time between surgery and the first passage of stool (mean difference, -9.38; 95% confidence interval, -17.60 to -1.16; P = .03). Although not statistically significant (P = .20), the overall effect favored shorter hospital stays for those patients receiving coffee. CONCLUSIONS: The current systematic review and meta-analysis suggests that coffee given as early as 2 hours postoperatively decreases time to first bowel movement. In addition, patients tolerated solid food faster and were discharged sooner when given coffee immediately postoperatively.

Measuring Adaptive Control in Conflict Tasks.

The past two decades have witnessed an explosion of interest in the cognitive and neural mechanisms of adaptive control processes that operate in selective attention tasks. This has spawned not only a large empirical literature and several theories but also the recurring identification of potential confounds and corresponding adjustments in task design to create confound-minimized metrics of adaptive control. The resulting complexity of this literature can be difficult to navigate for new researchers entering the field, leading to suboptimal study designs. To remediate this problem, we present here a consensus view among opposing theorists that specifies how researchers can measure four hallmark indices of adaptive control (the congruency sequence effect, and list-wide, context-specific, and item-specific proportion congruency effects) while minimizing easy-to-overlook confounds.

Context-specific proportion congruent effects: Compound-cue contingency learning in disguise.

Conflict between task-relevant and task-irrelevant stimulus information leads to impairment in response speed and accuracy. For instance, in the colour-word Stroop paradigm, participants respond slower and less accurately to the print colour of incongruent colour words (e.g., "red" printed in green) than to congruent colour words (e.g., "green" in green). Importantly, this congruency effect is diminished when the trials in an experiment are mostly incongruent, relative to mostly congruent, termed a proportion congruent effect. When distracting stimuli are mostly congruent in one context (e.g., location or font) but mostly incongruent in another context (e.g., another location or font), the congruency effect is still diminished in the mostly incongruent context, termed a context-specific proportion congruent (CSPC) effect. Both the standard proportion congruent and CSPC effects are typically interpreted in terms of conflict-driven attentional control, frequently termed conflict adaptation or conflict monitoring. However, in two experiments, we investigated contingency learning confounds in context-specific proportion congruent effects. In particular, two variants of a dissociation procedure are presented with the font variant of the CSPC procedure. In both, robust contingency learning effects were observed. No evidence for context-specific control was observed. In fact, results trended in the wrong direction. In all, the results suggest that CSPC effects may not be a useful way of studying attentional control.

The Law of Recency: An Episodic Stimulus-Response Retrieval Account of Habit Acquisition.

A habit is a regularity in automatic responding to a specific situation. Classical learning psychology explains the emergence of habits by an extended learning history during which the response becomes associated to the situation (learning of stimulus-response associations) as a function of practice ("law of exercise") and/or reinforcement ("law of effect"). In this paper, we propose the "law of recency" as another route to habit acquisition that draws on episodic memory models of automatic response regulation. According to this account, habitual responding results from (a) storing stimulus-response episodes in memory, and (b) retrieving these episodes when encountering the stimulus again. This leads to a reactivation of the response that was bound to the stimulus (c) even in the absence of extended practice and reinforcement. As a measure of habit formation, we used a modified color-word contingency learning (CL) paradigm, in which irrelevant stimulus features (i.e., word meaning) were predictive of the to-be-executed color categorization response. The paradigm we developed allowed us to assess effects of global CL and of an instance-based episodic response retrieval simultaneously within the same experiment. Two experiments revealed robust CL as well as episodic response retrieval effects. Importantly, these effects were not independent: Controlling for response retrieval effects eliminated effects of CL, which supports the claim that habit formation can be mediated by episodic retrieval processes, and that short-term binding effects are not fundamentally separate from long-term learning processes. Our findings have theoretical and practical implications regarding (a) models of long-term learning, and (b) the emergence and change of habitual responding.

High salt diet impairs cerebral blood flow regulation via salt-induced angiotensin II suppression.

OBJECTIVES: This study sought to determine whether salt-induced ANG II suppression contributes to impaired CBF autoregulation. METHODS: Cerebral autoregulation was evaluated with LDF during graded reductions of blood pressure. Autoregulatory responses in rats fed HS (4% NaCl) diet vs LS (0.4% NaCl) diet were analyzed using linear regression analysis, model-free analysis, and a mechanistic theoretical model of blood flow through cerebral arterioles. RESULTS: Autoregulation was intact in LS-fed animals as MAP was reduced via graded hemorrhage to approximately 50 mm Hg. Short-term (3 days) and chronic (4 weeks) HS diet impaired CBF autoregulation, as evidenced by progressive reductions of laser Doppler flux with arterial pressure reduction. Chronic low dose ANG II infusion (5 mg/kg/min, i.v.) restored CBF autoregulation between the pre-hemorrhage MAP and 50 mm Hg in rats fed short-term HS diet. Mechanistic-based model analysis showed a reduced myogenic response and reduced baseline VSM tone with short-term HS diet, which was restored by ANG II infusion. CONCLUSIONS: Short-term and chronic HS diet lead to impaired autoregulation in the cerebral circulation, with salt-induced ANG II suppression as a major factor in the initiation of impaired CBF regulation.

Evidence against conflict monitoring and adaptation: An updated review.

One of the most influential ideas in recent decades in the cognitive psychology literature is conflict monitoring theory. According to this account, each time we experience a conflict (e.g., between a colour word and print colour in the Stroop task), attentional control is upregulated to minimize distraction on subsequent trials. Though influential, evidence purported to support this theoretical model (primarily, proportion congruent and congruency sequence effects) has been frequently criticized. Furious debate has centered on whether or not conflict monitoring does or does not occur and, if so, under which conditions. The present article presents an updated review of this debate. In particular, the article considers new research that either (a) seems particularly damaging for the conflict monitoring view or (b) seems to provide support for the theory. The author argues that new findings of the latter sort are still not compelling, several of which have already-demonstrated confounds and others which are plausibly confounded. Further progress has, to a greater extent than not, provided even stronger support for the position that conflict monitoring is merely an illusion. Instead, the net results can be more coherently understood in terms of (relatively) simpler learning/memory biases unrelated to conflict or attention that confound the key paradigms.

Category learning in the color-word contingency learning paradigm.

In the typical color-word contingency learning paradigm, participants respond to the print color of words where each word is presented most often in one color. Learning is indicated by faster and more accurate responses when a word is presented in its usual color, relative to another color. To eliminate the possibility that this effect is driven exclusively by the familiarity of item-specific word-color pairings, we examine whether contingency learning effects can be observed also when colors are related to categories of words rather than to individual words. To this end, the reported experiments used three categories of words (animals, verbs, and professions) that were each predictive of one color. Importantly, each individual word was presented only once, thus eliminating individual color-word contingencies. Nevertheless, for the first time, a category-based contingency effect was observed, with faster and more accurate responses when a category item was presented in the color in which most of the other items of that category were presented. This finding helps to constrain episodic learning models and sets the stage for new research on category-based contingency learning.

Interference in Dutch-French Bilinguals.

In the present manuscript, we investigate the source of congruency effects in a group of Dutch-French bilinguals. In particular, participants performed a color-identification Stroop task, in which both (first language) Dutch and (second language) French distracting color words were presented in colors. The typical finding is impaired responding when the word and color are incongruent (e.g., "red" in blue) relative to congruent (e.g., "red" in red). This congruency effect is observed for both first and second language distracting color words. The current experiment used a 2-to-1 keypress mapping manipulation, which allows one to separate stimulus conflict (i.e., conflict between word and color meanings) and response conflict (i.e., conflict between potential responses). For both the first and second language, both stimulus and response conflict were observed. These results suggest that second language words influence semantic and response processing similarly to first language words, rather than having diminished semantic and/or response influences.

Best not to bet on the horserace: A comment on Forrin and MacLeod (2017) and a relevant stimulus-response compatibility view of colour-word contingency learning asymmetries.

One powerfully robust method for the study of human contingency learning is the colour-word contingency learning paradigm. In this task, participants respond to the print colour of neutral words, each of which is presented most often in one colour. The contingencies between words and colours are learned, as indicated by faster and more accurate responses when words are presented in their expected colour relative to an unexpected colour. In a recent report, Forrin and MacLeod (2017b, Memory & Cognition) asked to what extent this performance (i.e., response time) measure of learning might depend on the relative speed of processing of the word and the colour. With keypress responses, learning effects were comparable when responding to the word and to the colour (contrary to predictions). However, an asymmetry appeared in a second experiment with vocal responses, with a contingency effect only present for colour identification. In a third experiment, the colour was preexposed, and contingency effects were again roughly symmetrical. In their report, they suggested that a simple speed-of-processing (or "horserace") model might explain when contingency effects are observed in colour and word identification. In the present report, an alternative view is presented. In particular, it is argued that the results are best explained by appealing to the notion of relevant stimulus-response compatibility, which also resolves discrepancies between horserace model predictions and participant results. The article presents simulations with the Parallel Episodic Processing model to demonstrate this case.

Evaluation of Vascular Control Mechanisms Utilizing Video Microscopy of Isolated Resistance Arteries of Rats.

This protocol describes the use of in vitro television microscopy to evaluate vascular function in isolated cerebral resistance arteries (and other vessels), and describes techniques for evaluating tissue perfusion using Laser Doppler Flowmetry (LDF) and microvessel density utilizing fluorescently labeled Griffonia simplicifolia (GS1) lectin. Current methods for studying isolated resistance arteries at transmural pressures encountered in vivo and in the absence of parenchymal cell influences provide a critical link between in vivo studies and information gained from molecular reductionist approaches that provide limited insight into integrative responses at the whole animal level. LDF and techniques to selectively identify arterioles and capillaries with fluorescently-labeled GS1 lectin provide practical solutions to enable investigators to extend the knowledge gained from studies of isolated resistance arteries. This paper describes the application of these techniques to gain fundamental knowledge of vascular physiology and pathology in the rat as a general experimental model, and in a variety of specialized genetically engineered "designer" rat strains that can provide important insight into the influence of specific genes on important vascular phenotypes. Utilizing these valuable experimental approaches in rat strains developed by selective breeding strategies and new technologies for producing gene knockout models in the rat, will expand the rigor of scientific premises developed in knockout mouse models and extend that knowledge to a more relevant animal model, with a well understood physiological background and suitability for physiological studies because of its larger size.

Time-out for conflict monitoring theory: Preventing rhythmic biases eliminates the list-level proportion congruent effect.

The proportion congruent (PC) effect is the observation that congruency effects are smaller when most trials are incongruent rather than congruent. The list-level PC (LLPC) effect is the finding that a PC effect can transfer from biased inducer items to unbiased diagnostic items. Such effects are generally interpreted as resulting from conflict monitoring and attentional adaptation. An alternative view proposes that PC effects result from simple learning biases unrelated to conflict. The temporal learning account proposes that LLPC effects stem from a different task rhythm in the mostly congruent and mostly incongruent conditions. Two prime-probe experiments provide a critical test of this notion. In both, half of the participants were forced to withhold responding for a short period of time on inducer trials. This equates the task rhythm in the mostly congruent and mostly incongruent lists, while still maintaining differing levels of conflict. Consistent with the temporal learning account, but inconsistent with the conflict monitoring account, the LLPC effect was eliminated when rhythms were equated. (PsycINFO Database Record