A dimensional summation account of polymorphous category learning.

Polymorphous concepts are hard to learn, and this is perhaps surprising because they, like many natural concepts, have an overall similarity structure. However, the dimensional summation hypothesis (Milton and Wills Journal of Experimental Psychology: Learning, Memory and Cognition, 30, 407-415 2004) predicts this difficulty. It also makes a number of other predictions about polymorphous concept formation, which are tested here. In Experiment 4, we confirm the theory's prediction that polymorphous concept formation should be facilitated by deterministic pretraining on the constituent features of the stimulus. This facilitation is relative to an equivalent amount of training on the polymorphous concept itself. In further experiments, we compare the predictions of the dimensional summation hypothesis with a more general strategic account (Experiment 2), a seriality of training account (Experiment 3), a stimulus decomposition account (also Experiment 3), and an error-based account (Experiment 4). The dimensional summation hypothesis provides the best account of these data. In Experiment 5, a further prediction is confirmed-the single feature pretraining effect is eliminated by a concurrent counting task. The current experiments suggest the hypothesis that natural concepts might be acquired by the deliberate serial summation of evidence. This idea has testable implications for classroom learning.

Goal-Directed and Habit-Like Modulations of Stimulus Processing during Reinforcement Learning.

Recent research has shown that perceptual processing of stimuli previously associated with high-value rewards is automatically prioritized even when rewards are no longer available. It has been hypothesized that such reward-related modulation of stimulus salience is conceptually similar to an "attentional habit." Recording event-related potentials in humans during a reinforcement learning task, we show strong evidence in favor of this hypothesis. Resistance to outcome devaluation (the defining feature of a habit) was shown by the stimulus-locked P1 component, reflecting activity in the extrastriate visual cortex. Analysis at longer latencies revealed a positive component (corresponding to the P3b, from 550-700 ms) sensitive to outcome devaluation. Therefore, distinct spatiotemporal patterns of brain activity were observed corresponding to habitual and goal-directed processes. These results demonstrate that reinforcement learning engages both attentional habits and goal-directed processes in parallel. Consequences for brain and computational models of reinforcement learning are discussed.SIGNIFICANCE STATEMENT The human attentional network adapts to detect stimuli that predict important rewards. A recent hypothesis suggests that the visual cortex automatically prioritizes reward-related stimuli, driven by cached representations of reward value; that is, stimulus-response habits. Alternatively, the neural system may track the current value of the predicted outcome. Our results demonstrate for the first time that visual cortex activity is increased for reward-related stimuli even when the rewarding event is temporarily devalued. In contrast, longer-latency brain activity was specifically sensitive to transient changes in reward value. Therefore, we show that both habit-like attention and goal-directed processes occur in the same learning episode at different latencies. This result has important consequences for computational models of reinforcement learning.

A simple algorithm for the offline recalibration of eye-tracking data through best-fitting linear transformation.

Poor calibration and inaccurate drift correction can pose severe problems for eye-tracking experiments requiring high levels of accuracy and precision. We describe an algorithm for the offline correction of eye-tracking data. The algorithm conducts a linear transformation of the coordinates of fixations that minimizes the distance between each fixation and its closest stimulus. A simple implementation in MATLAB is also presented. We explore the performance of the correction algorithm under several conditions using simulated and real data, and show that it is particularly likely to improve data quality when many fixations are included in the fitting process.

Out of control: an associative account of congruency effects in sequence learning.

The demonstration of a sequential congruency effect in sequence learning has been offered as evidence for control processes that act to inhibit automatic response tendencies (Jiménez, Lupiáñez, & Vaquero, 2009) via unconscious conflict monitoring. Here we propose an alternative interpretation of this effect based on the associative learning of chains of sequenced contingencies. This account is supported by simulations with a Simple Recurrent Network, an associative (connectionist) model of sequence learning. We argue that the control- and associative-based accounts differ in their predictions concerning the magnitude of the sequential congruency effect across training. These predictions are tested by reanalysing data from a study by Shanks, Wilkinson, and Channon (2003). The results support the associative learning account which explains the sequential congruency effect without appealing to control processes (either conscious or unconscious).

Examining the role of depth information in contextual cuing using a virtual reality visual search task.

Two experiments examined the role that depth plays in the formation of associations during contextual cuing of visual search. Current associative models make predictions about the spatial constraints placed on learning within two-dimensional procedures, but there exists very little evidence of how these predictions translate to three-dimensional space. A virtual reality procedure was used to project the stimuli in three dimensions. Experiment 1 established a contextual cuing effect using this procedure, while Experiment 2 examined whether the relative distance between repeated distractors and the target or the position of the distractors relative to the observer modulated contextual cuing. It was found that the contextual cuing effect was consistent across these different conditions. As a result, there was no evidence to suggest that depth information forms a significant part of the representations that form during contextual cuing. These data are therefore broadly consistent with the mechanisms of current associative models of contextual cuing. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Protection from uncertainty in the exploration/exploitation trade-off.

The exploration/exploitation trade-off (EE trade-off) describes how, when faced with several competing alternatives, decision-makers must often choose between a known good alternative (exploitation) and one or more unknown but potentially more rewarding alternatives (exploration). Prevailing theory on how humans perform the EE trade-off states that uncertainty is a major motivator for exploration: the more uncertain the environment, the more exploration that will occur. The current article examines whether exploratory behavior in both choice and attention may be impacted differently depending on whether uncertainty is onset suddenly (unexpected uncertainty), or more slowly (expected uncertainty). It is shown that when uncertainty was expected, participants tended to explore less with their choices, but not their attention, than when it was unexpected. Crucially, the impact of this "protection from uncertainty" on exploration only occurred when participants had an opportunity to learn the structure of the task before experiencing uncertainty. This suggests that the interaction between uncertainty and exploration is more nuanced than simply more uncertainty leading to more exploration, and that attention and choice behavior may index separate aspects of the EE trade-off. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Contextual cuing of visual search does not guide attention automatically in the presence of top-down goals.

Visual search is faster when it occurs within repeated displays, a phenomenon known as contextual cuing (CC). CC has been explained as the result of an automatic orientation of attention toward a target item driven by learned distractor-target associations. In 3 experiments we tested the specific hypothesis that CC is an automatic process of attentional guidance. Participants first searched for a T target in a standard CC procedure. Then, they experienced the same repeated configurations (with the T still present), but now searched for a Y target that was positioned either in a location on the same, or on a different side, from the old T target. Results suggested that there was no interference caused by the old T-target: target search was not affected by the relative positions of the T and Y. Instead, we found a general facilitation in search times for repeated configurations (Experiments 1 and 2). This main effect disappeared when the need for visual search was eliminated in Experiment 3 using a "feature search task". These results suggest that repeated sets of distractors did not trigger an uncontrollable response toward the position of the T; instead, CC was produced by perceptual learning processes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

There is more to contextual cuing than meets the eye: Improving visual search without attentional guidance toward predictable target locations.

It is usually easier to find objects in a visual scene as we gain familiarity with it. Two decades of research on contextual cuing of visual search show that repeated exposure to a search display can facilitate the detection of targets that appear at predictable locations in that display. Typical accounts for this effect attribute an essential role to learned associations between the target and other stimuli in the search display. These associations improve visual search either by driving attention toward the usual location of the target or by facilitating its recognition. Contrary to this view, we show that a robust contextual cuing effect can also be observed when repeated search displays do not allow the location of the target to be predicted. These results suggest that, in addition to the mechanisms already explored by previous research, participants learn to ignore the locations usually occupied by distractors, which in turn facilitates the detection of targets even when they appear in unpredictable locations. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Testing the automaticity of an attentional bias towards predictive cues in human associative learning.

It is well established that associative learning, such as learning new cue-outcome pairings, produces changes in attention: cues that are good predictors of relevant outcomes become prioritised compared with those that are non-predictive or redundant. However, there is controversy about whether such a learnt attentional bias results from a controlled orientation of attention, or whether it can be involuntary in nature. In three experiments, participants learned that cues of certain colours were predictive or non-predictive, and we assessed attention to cues using a dot-probe task. On dot-probe trials, participants were instructed to control attention by orienting towards a cue of a certain shape (target), while trying to ignore another cue (distractor). Although the colours of the cues were critical for the associative learning task, they were irrelevant for the dot-probe task. The results show that, even though participants' controlled attention was focused on the target shape (as evident in response times and accuracy data), response times to the probe were slower (Experiments 1 and 2) and error rates were higher (Experiments 2 and 3) when the distractor was of a (previously) predictive colour. These data suggest that attention was captured involuntarily by the predictive value of the distractor, despite this being counterproductive to the task goal.

Failures of executive function when at a height: Negative height-related appraisals are associated with poor executive function during a virtual height stressor.

It is difficult to maintain cognitive functioning in threatening contexts, even when it is imperative to do so. Research indicates that precarious situations can impair subsequent executive functioning, depending on whether they are appraised as threatening. Here, we used virtual reality to place participants at ground level or at a virtual height in order to examine the impact of a threat-related context on concurrent executive function and whether this relationship was modulated by negative appraisals of heights. Executive function was assessed via the Go/NoGo and N-Back tasks, indexing response inhibition and working memory updating respectively. Participants with negative appraisals of heights exhibited impaired executive function on both tasks when performing at a virtual height (i.e., a threat-related context) but not at ground-level, demonstrating the importance of considering the cognitive consequences of individual differences in negative interpretations of emotionally-evocative situations. We suggest that a virtual reality approach holds practical benefits for understanding how individuals are able to maintain cognitive ability when embedded within threatening situations.

Learned predictiveness models predict opposite attention biases in the inverse base-rate effect.

Several attention-based models of associative learning are built upon the learned predictiveness principle, whereby learning is optimized by attending to the most predictive features and ignoring the least predictive features. Despite their functional similarity, these models differ in their formal mechanisms and thus may produce very different predictions in some circumstances. As we demonstrate, this is particularly evident in the inverse base-rate effect. Using simulations with a modified Mackintosh model and the EXIT model, we found that models based on the learned predictiveness principle can account for rare-outcome choice biases associated with the inverse base-rate effect, despite making opposite predictions for relative attention to rare versus common predictors. The models also make different predictions regarding changes in attention across training, and effects of context associations on attention to cues. Using a human causal learning task, we replicated the inverse base-rate effect and a recently reported reduction in this effect when the context is not predictive of the common outcome and used eye-tracking to test model predictions about changes in attention both prior to making a decision, and during feedback. The results support the predictions made by EXIT, where the rare predictor commands greater attention than the common predictor throughout training. In addition, patterns of attention prior to making a decision differed to those during feedback, where effects of using a partially predictive context were evident only prior to making a prediction. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The onset of uncertainty facilitates the learning of new associations by increasing attention to cues.

Past research in animals has suggested that attention is distributed to exploit known relationships between stimuli and explore stimuli whose consequences are uncertain. While there is strong support for exploitative attention and its effects on learning in humans, the evidence for exploratory attention is less well developed. Two experiments examined whether preferential allocation of attention (as measured by eye-gaze) to cues associated with uncertainty leads to more rapid learning of new associations involving these cues in the future. In each experiment, participants first learned about compounds containing one predictive cue and one nonpredictive cue. The level of uncertainty during this first stage of training was also manipulated: cue-outcome relationships were either deterministic (certain) or probabilistic (uncertain). In a second stage, new cue-outcome relationships were trained and the uncertainty of these relationships could be resolved by learning about the previously nonpredictive cues. As a result of the manipulation of uncertainty in the first stage, some participants experienced a sudden onset of uncertainty at the start of this second stage, while others experienced a stable level of uncertainty throughout the experiment. Experiment 1 showed that the former learned novel cue-outcome associations faster than participants for whom uncertainty was constant. Furthermore, participants experiencing unexpected uncertainty showed a greater increase in attention to cues in Stage 2. Extending the training stage in Experiment 2 resulted in a larger difference in rate of learning between conditions in stage 2. We argue that this represents evidence for an effect of exploratory attention on rate of learning in humans.

The role of uncertainty in attentional and choice exploration.

The exploitation-exploration (EE) trade-off describes how, when making a decision, an organism must often choose between a safe alternative with a known pay-off, and one or more riskier alternatives with uncertain pay-offs. Recently, the concept of the EE trade-off has been extended to the examination of how organisms distribute limited attentional resources between several stimuli. This work suggests that when the rules governing the environment are certain, participants learn to "exploit" by attending preferentially to cues that provide the most information about upcoming events. However, when the rules are uncertain, people "explore" by increasing their attention to all cues that may provide information to help in predicting upcoming events. In the current study, we examine how uncertainty affects the EE trade-off in attention using a contextual two-armed bandit task, where participants explore with both their attention and their choice behavior. We find evidence for an influence of uncertainty on the EE trade-off in both choice and attention. These findings provide support for the idea of an EE trade-off in attention, and that uncertainty is a primary motivator for exploration in both choice and attentional allocation.

Outcome predictability biases cued search.

Within the domain of associative learning, there is substantial evidence that people (and other animals) select among environmental cues on the basis of their reinforcement history. Specifically, people preferentially attend to, and learn about, cueing stimuli that have previously predicted events of consequence (a predictiveness bias). By contrast, relatively little is known about whether people prioritize some (to-be-predicted) outcome events over others on the basis of their past experience with those outcomes (a predictability bias). The present experiments assessed whether the prior predictability of a stimulus results in a learning bias in a contingency learning task, as such effects are not anticipated by formal models of associative learning. Previously unpredictable stimuli were less readily learned about than previously predictable stimuli. This pattern is unlikely to reflect the use of strategic search processes or blocking of learning by the context. Instead we argue that our findings are most consistent with the operation of a biased learning mechanism. (PsycINFO Database Record

Overt attention in contextual cuing of visual search is driven by the attentional set, but not by the predictiveness of distractors.

Two experiments examined biases in selective attention during contextual cuing of visual search. When participants were instructed to search for a target of a particular color, overt attention (as measured by the location of fixations) was biased strongly toward distractors presented in that same color. However, when participants searched for targets that could be presented in 1 of 2 possible colors, overt attention was not biased between the different distractors, regardless of whether these distractors predicted the location of the target (repeating) or did not (randomly arranged). These data suggest that selective attention in visual search is guided only by the demands of the target detection task (the attentional set) and not by the predictive validity of the distractor elements. (PsycINFO Database Record

Spatiotemporal competition and task-relevance shape the spatial distribution of emotional interference during rapid visual processing: Evidence from gaze-contingent eye-tracking.

People's ability to perceive rapidly presented targets can be disrupted both by voluntary encoding of a preceding target and by spontaneous attention to salient distractors. Distinctions between these sources of interference can be found when people search for a target in multiple rapid streams instead of a single stream: voluntary encoding of a preceding target often elicits subsequent perceptual lapses across the visual field, whereas spontaneous attention to emotionally salient distractors appears to elicit a spatially localized lapse, giving rise to a theoretical account suggesting that emotional distractors and subsequent targets compete spatiotemporally during rapid serial visual processing. We used gaze-contingent eye-tracking to probe the roles of spatiotemporal competition and memory encoding on the spatial distribution of interference caused by emotional distractors, while also ruling out the role of eye-gaze in driving differences in spatial distribution. Spontaneous target perception impairments caused by emotional distractors were localized to the distractor location regardless of where participants fixated. But when emotional distractors were task-relevant, perceptual lapses occurred across both streams while remaining strongest at the distractor location. These results suggest that spatiotemporal competition and memory encoding reflect a dual-route impact of emotional stimuli on target perception during rapid visual processing.

Attenuation of visual evoked responses to hand and saccade-initiated flashes.

Sensory attenuation refers to reduced brain responses to self-initiated sensations relative to those produced by the external world. It is a low-level process that may be linked to higher-level cognitive tasks such as reality monitoring. The phenomenon is often explained by prediction error mechanisms of universal applicability to sensory modality; however, it is most widely reported for auditory stimuli resulting from self-initiated hand movements. The present series of event-related potential (ERP) experiments explored the generalizability of sensory attenuation to the visual domain by exposing participants to flashes initiated by either their own button press or volitional saccade and comparing these conditions to identical, computer-initiated stimuli. The key results showed that the largest reduction of anterior visual N1 amplitude occurred for saccade-initiated flashes, while button press-initiated flashes evoked an intermediary response between the saccade-initiated and externally initiated conditions. This indicates that sensory attenuation occurs for visual stimuli and suggests that the degree of electrophysiological attenuation may relate to the causal likelihood of pairings between the type of motor action and the modality of its sensory response.

Prediction and uncertainty in associative learning: examining controlled and automatic components of learned attentional biases.

It has been suggested that attention is guided by two factors that operate during associative learning: a predictiveness principle, by which attention is allocated to the best predictors of outcomes, and an uncertainty principle, by which attention is allocated to learn about the less known features of the environment. Recent studies have shown that predictiveness-driven attention can operate rapidly and in an automatic way to exploit known relationships. The corresponding characteristics of uncertainty-driven attention, on the other hand, remain unexplored. In two experiments we examined whether both predictiveness and uncertainty modulate attentional processing in an adaptation of the dot probe task. This task provides a measure of automatic orientation to cues during associative learning. The stimulus onset asynchrony of the probe display was manipulated in order to explore temporal characteristics of predictiveness- and uncertainty-driven attentional effects. Results showed that the predictive status of cues determined selective attention, with faster attentional capture to predictive than to non-predictive cues. In contrast, the level of uncertainty slowed down responses to the probe regardless of the predictive status of the cues. Both predictiveness- and uncertainty-driven attentional effects were very rapid (at 250 ms from cue onset) and were automatically activated.

Sequential effects and sequence learning in a three-choice serial reaction time task.

The recent history of events can influence responding despite there being no contingent relationship between those events. These 'sequential effects' are ubiquitous in cognitive psychology, yet their study has been dominated by two-choice reaction time tasks in which sequences necessarily comprise simple response repetitions and alternations. The current study explored sequential effects in a three-choice reaction time task where the target was constrained to either move clockwise or anticlockwise on each trial, allowing for assessment of sequential effects involving the direction of target transitions rather than target location. Across two experiments, a reliable pattern of sequential effects was found in the absence of contingencies, whereby the most notable feature was that participants were fastest to respond to subsequences where the target moved in a consistent direction on consecutive trials, compared to when the target direction alternated. In Experiment 2, the direction of motion was biased to move in one direction 75% of the time and in a subsequent transfer phase, participants showed evidence of learning this probabilistic sequence but still exhibited the same pattern of sequential effects on trials where the target moved in the more prevalent or less prevalent direction. Simulations with a connectionist model of sequence learning (the Augmented Serial Recurrent Network, Cleeremans & McClelland, 1991) produced an adequate replication of the sequential effects in both experiments in addition to an effect of sequence learning in Experiment 2. We propose that sequential effects may represent learning about transient contingencies and may be described using the same associative learning mechanisms intended for sequence learning.

Attenuation of auditory evoked potentials for hand and eye-initiated sounds.

Reduction of auditory event-related potentials (ERPs) to self-initiated sounds has been considered evidence for a predictive model in which copies of motor commands suppress sensory representations of incoming stimuli. However, in studies which involve arbitrary auditory stimuli evoked by sensory-unspecific motor actions, learned associations may underlie ERP differences. Here, in a new paradigm, eye motor output generated auditory sensory input, a naïve action-sensation contingency. We measured the electroencephalogram (EEG) of 40 participants exposed to pure tones, which they produced with either a button-press or volitional saccade. We found that button-press-initiated stimuli evoked reduced amplitude compared to externally initiated stimuli for both the N1 and P2 ERP components, whereas saccade-initiated stimuli evoked intermediate attenuation at N1 and no reduction at P2. These results indicate that the motor-to-sensory mapping involved in speech production may be partly generalized to other contingencies, and that learned associations also contribute to the N1 attenuation effect.