Executive control of actions across time and space

ReviewThis is the author accepted manuscript. The final version is available from Sage via the DOI in this record.Many popular psychological accounts attribute adaptive human behavior to an ‘executive control’ system that regulates a lower-level ‘impulsive’ or ‘associative’ system. However, recent findings argue against this strictly hierarchical view. Instead, control of impulsive and inappropriate actions depends on an interplay between multiple basic cognitive processes. The outcome of these processes can be biased in advance. Action control is also strongly influenced by personal experiences in the recent and distant past. Thus, executive control emerges from an interactive and competitive network. Main challenges for future research are to describe and understand these interactions, and to put executive action control in a wider socio-cultural and evolutional context.The author is currently supported by a starting grant from the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP7/2007-2013)/ ERC Grant Agreement No. 312445

Effects of reward and punishment on the interaction between going and stopping in a selective stop-change task

Dataset available at: http://hdl.handle.net/10871/24540Inhibition of no-longer relevant go responses supports flexible and goal-directed behavior. The present study explored if the interaction between going and stopping is influenced by monetary incentives. Subjects (N = 108) performed a selective stop-change task, which required them to stop and change a go response if a valid signal occurred, but to execute the planned go response if invalid signals or no signals occurred. There were two incentive groups: the punishment group lost points for unsuccessful valid-signal trials, whereas the reward group gained points for successful valid-signal trials. There was also a control group that could not win or lose points on any trials. We found that, compared with the control group, incentives encouraged subjects to slow down on no-signal trials, suggesting proactive control adjustments. Furthermore, latencies of valid change responses were shorter in the incentive groups than in the control group, suggesting improvements in executing an alternative response. However, incentives did not modulate stop latency or the interaction between going and stopping on valid-signal trials much. Finally, Bayesian analyses indicated that there was no difference between the reward and punishment groups. These findings are inconsistent with the idea that reward and punishment have distinct effects on stop performance.This study was supported by a starting grant to FV from the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP7/2007-2013)/ ERC Grant Agreement No. 312445. FV is also supported by a Royal Society Wolfson Research Merit Award

Effects of reward and punishment on the interaction between going and stopping in a selective stop-change task (dataset)

This data is related to the article 'Effects of reward and punishment on the interaction between going and stopping in a selective stop-change task' to be published by Springer in Psychological Research. Available at: http://hdl.handle.net/10871/24543Behavioural data and R scripts (analyses) for a behavioural experiment. Experiment documentation is included as well

What can Associative Learning do for Driving?

This is the final version of the paper. Available from Cognitive Science Society via the link in this record.To improve road safety, it is important to understand the impact that the contingencies around traffic lights have upon drivers’ behavior. There are formal rules that govern behavior at UK traffic lights (see The Highway Code, 2015), but what does experience of the contingencies do to us? While a green light always cues a go response and a singleton red a stop, the behavior linked to amber is ambiguous; in the presence of red it cues readiness to start, while on its own it cues "preparation" to stop. Could it be that the contingencies between stimuli and responses lead to implicit learning of responses that differ from those suggested by the rules of the road? This study used an incidental go/no-go task in which colored shapes were stochastically predictive of whether a response was required. The stimuli encoded the contingencies between traffic lights and their appropriate responses, for example, stimulus G was a go cue, mimicking the response to a green light. Evidence was found to indicate that G was a go cue, while A (which had the same contingencies as an amber light) was a weak go cue, and that R (a stop cue) was surprisingly responded to as a neutral cue.W.G.N. is supported by an ERSC studentship (ES/J50015X/1)

Instructed and acquired contingencies in response-inhibition tasks

This is the author accepted manuscript. The final version is available from Ubiquity Press via the DOI in this record.Inhibitory control can be triggered directly via the retrieval of previously acquired stimulusstop associations from memory. However, a recent study suggests that this item-specific stop learning may be mediated via expectancies of the contingencies in play (Best, Lawrence, Logan, McLaren, & Verbruggen, 2016). This could indicate that stimulus-stop learning also induces strategic, proactive changes in performance. We further tested this hypothesis in the present study. In addition to measuring expectancies following task completion, we introduced a between-subjects expectancy manipulation in which one group of participants were informed about the stimulus-stop contingencies and another group did not receive any information about the stimulus-stop contingencies. Moreover, we combined this instruction manipulation with a distractor manipulation that was previously used to examine strategic proactive adjustments. We found that the stop-associated items slowed responding in both conditions. Furthermore, participants in both conditions generated expectancies following task completion that were consistent with the stimulus-stop contingencies. The distractor manipulation was ineffective. However, we found differences in the relationship between the expectancy ratings and task performance: in the instructed condition, the expectancies reliably correlated with the response slowing for the stop-associated items, whereas in the uninstructed condition we found no reliable correlation. These differences between the correlations were reliable, and our conclusions were further supported by Bayesian analyses. We conclude that stimulus-stop associations that are acquired either via task instructions or via task practice have similar effects on behavior but could differ in how they elicit response slowing.Economic and Social Research Council (ESRC

Transfer of learned category-response associations is modulated by instruction (article)

The dataset associated with this article is available at http://hdl.handle.net/10871/27115This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Although instructions often emphasize categories (e.g., odd number → left hand response) rather than specific stimuli (e.g., 3 → left hand response), learning is often interpreted in terms of stimulus-response (S-R) bindings or, less frequently, stimulus-classification (S-C) bindings with little attention being paid to the importance of category-response (C-R) bindings. In a training-transfer paradigm designed to investigate the early stages of category learning, participants were required to classify stimuli according to the category templates presented prior to each block (Experiments 1-4). In some transfer blocks the stimuli, categories and/or responses could be novel or repeated from the preceding training phase. Learning was assessed by comparing the transfer-training performance difference across conditions. Participants were able to rapidly transfer C-R associations to novel stimuli but evidence of S-C transfer was much weaker and S-R transfer was largely limited to conditions where the stimulus was classified under the same category. Thus, even though there was some evidence that learned S-R and S-C associations contributed to performance, learned C-R associations seemed to play a much more important role. In a final experiment (Experiment 5) the stimuli themselves were presented prior to each block, and the instructions did not mention the category structure. In this experiment, the evidence for S-R learning outweighed the evidence for C-R learning, indicating the importance of instructions in learning. The implications for these findings to the learning, cognitive control, and automaticity literatures are discussed.This work was supported by the European Research Council (grant number 312445). Frederick Verbruggen is a Royal Society Wolfson Research Merit Award holder

Training response inhibition to reduce food consumption: Mechanisms, stimulus specificity and appropriate training protocols.

Published onlineJournal ArticleThis is the final version of the article. Available from Elsevier via the DOI in this record.Training individuals to inhibit their responses towards unhealthy foods has been shown to reduce food intake relative to a control group. Here we aimed to further explore these effects by investigating the role of stimulus devaluation, training protocol, and choice of control group. Restrained eaters received either inhibition or control training using a modified version of either the stop-signal or go/no-go task. Following training we measured implicit attitudes towards food (Study 1) and food consumption (Studies 1 and 2). In Study 1 we used a modified stop-signal training task with increased demands on top-down control (using a tracking procedure and feedback to maintain competition between the stop and go processes). With this task, we found no evidence for an effect of training on implicit attitudes or food consumption, with Bayesian inferential analyses revealing substantial evidence for the null hypothesis. In Study 2 we removed the feedback in the stop-signal training to increase the rate of successful inhibition and revealed a significant effect of both stop-signal and go/no-go training on food intake (compared to double-response and go training, respectively) with a greater difference in consumption in the go/no-go task, compared with the stop-signal task. However, results from an additional passive control group suggest that training effects could be partly caused by increased consumption in the go control group whereas evidence for reduced consumption in the inhibition groups was inconclusive. Our findings therefore support evidence that inhibition training tasks with higher rates of inhibition accuracy are more effective, but prompt caution for interpreting the efficacy of laboratory-based inhibition training as an intervention for behaviour change.This project was supported by a PhD studentship from the School of Psychology, Cardiff University (to R. Adams) and a Biotechnology and Biological Sciences Research Council Grant (BB/K008277/1) to C. Chambers and F. Verbruggen. F Verbruggen is supported by a starting grant from the European Research Council (ERC) under the European Union’s Seventh Framework Programme (FP7/2007–2013)/ERC Grant Agreement No. 312445. R. Adams was principally responsible for all parts of the paper. N. Lawrence, F. Verbruggen and C. Chambers made substantial contributions to all parts of the paper. C. Chambers was senior author and oversaw the project

Winning and losing: Effects on impulsive action

In the present study, we examined the effect of wins and losses on impulsive action in gambling (Experiments 1-3) and non-gambling tasks (Experiments 4-5). In each experiment, subjects performed a simple task in which they had to win points. On each trial, they had to choose between a gamble and a non-gamble. The gamble was always associated with a higher amount but a lower probability of winning than the non-gamble. After subjects indicated their choice (i.e. gamble or not), feedback was presented. They had to press a key to start the next trial. Experiments 1-3 showed that, compared to the non-gambling baseline, subjects were faster to initiate the next trial after a gambled loss, indicating that losses can induce impulsive actions. In Experiments 4 and 5, subjects alternated between the gambling task and a neutral decision-making task in which they could not win or lose points. Subjects were faster in the neutral decision-making task if they had just lost in the gambling task, suggesting that losses have a general effect on action. Our results challenge the dominant idea that humans become more cautious after suboptimal outcomes. Instead, they indicate that losses in the context of potential rewards are emotional events that increase impulsivity.This work was supported by an Economic and Social Research Council Grant (ES/J00815X/1) to FV, CDC & IPLM, a starting grant to FV from the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP7/2007-2013)/ ERC Grant Agreement No. 312445, and a Biotechnology and Biological Sciences Research Council Grant (BB/K008277/1) to CDC and FV

Structure and implementation of novel task rules: A cross-sectional developmental study

This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.Rule-based performance improves remarkably throughout childhood. The present study examined how children and adolescents structured tasks and implemented rules when novel task instructions were presented in a child-friendly version of a novel instruction-learning paradigm. Each mini-block started with the presentation of the new stimulus-response mappings for a GO task. Prior to implementing this mapping, responses were required to advance through screens during a preparatory (NEXT) phase. Children (4-11 years) and late adolescents (17-19 years) responded more slowly during the NEXT phase when the NEXT response was incompatible with the instructed stimulus-response mapping. This instructionbased interference effect was more pronounced in young children than in older children. We argue that these findings are most consistent with age-related differences in rule structuring. We discuss the implications of our findings for theories of rule-based performance, instruction-based learning, and development.This work was supported by an ERC starting grant to FV (No. 312445)

Hunting for nuclear markers in green algal lineages: molecular evolution of glucose-6-phosphate isomerase

The Chlorophyta exhibit a remarkable cytological diversity ranging from unicellular microscopic algae with a single nucleus, over multicellular filaments and foliose blades, to coencytic and even siphonous life forms that are essentially composed of a giant cell containing thousands of nuclei. Unravelling the evolutionary history of this diverse and evolutionary old group is a difficult task due to the antiquity of the major lineages and considerable rate variation between those lineages for the commonly used 18S ribosomal DNA sequences and chloroplast markers (Lewis et al., Therefore different genes with known function and sequence data available are tested and more recently a cDNA library is screened to search for new useful genes.Glucose-6-phosphate isomerase (G6PI) is one of the genes we are testing. It is an important enzyme of the carbohydrate biosynthesis pathway in photosynthetic organisms and of the glycolysis in all organisms. Little is known about copy number of the gene in the Chlorophyta. The complete genome sequences of Chlamydomonas reinhardtii and Ostreococcus taur revealed that both have a single copy of G6PI. In plants however within a single genus there are species with one G6PI gene and other species with two G6PI (e.g. Arabidopsis, Actinidia,…) and up to thre copies are observed in Zea mays. It always concerns recent duplication within one genus.To investigate if the G6PI gene(s) is useful as a phylogenetic marker in the Chlorophyta, primers were made based on the G6PI genome sequences of Arabidopsis thaliana, Oryza sativa, Chlamydomonas reinhardtii and Ostreococcus tauri. The primers were tested on DNA and RNA of a variety of green algae.Following conclusions can be drawn from these preliminary results: 1. epiphytic or endophytic bacteria interfere with the direct amplification of nuclear genes; 2. the G6PI gene is informative on several taxonomic levels: for deep phylogenies we have to use a codon substitution model, for species level relationships introns may offer opportunities towards studies at the interspecific level; 3. most likely only one (functional) copy of the G6PI gene is present in the tested taxa