32 research outputs found
The effect of experience and instructions on learned attentional biases
Afiliaciones: Instituto de Investigación Biomédica de Målaga (IBIMA), University of Malaga, Spain
Primary Care and Public Health Sciences, Kingâs College London, UK
School of Psychology, UNSW Australia, Sydney, AustraliaIt has been shown that selective attention is allocated to the best available predictor of an outcome, which is known as learned predictiveness. Mitchell et al. (2012) have shown that instructions about the ârelevanceâ of each stimulus can influence (and even reverse) the learned predictiveness attentional bias, suggesting that propositional reasoning plays a crucial role in this phenomenon. Our experiment further explores the effects of instructions on this learned attentional bias. As a difference with previous work, we measured attentional capture through spatial cueing effects, which have been found to rely on rapid attentional processes (Le Pelley et al., 2013). Participants responded faster to events presented in the spatial location cued by stimuli that had previously been trained as predictive through trial-by-trial learning. However, verbal instructions regarding relevance failed to speed up participantsâ responses or to modulate the effect of learned predictiveness on spatial cueing. These results suggest that predictive stimuli produce an attentional bias which is not (always) under voluntary control.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tech
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 âexploitâ by attending preferentially to cues that provide the most information about upcoming events. However, when the rules are uncertain, people âexploreâ 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
Dynamic measurements of pressures, sail shape and forces on a full-scale spinnaker
This work presents a full-scale experimental study on a sailing yacht in downwind conditions with simultaneous time-resolved measurements of pressures, sail shape and loads. Those on-water experiments on a J/80 class yacht permit the dynamic behaviour of the fluid structure system made of a light cloth sail and highly curved flow to be investigated. Aerodynamic forces on the asymmetric spinnaker were determined from pressure distribution and shape measurements and also from strain gauges located on the corners of the sail. Both time-averaged and instantaneous data are analysed. The time-averaged pressures and forces were studied according to the apparent wind angle. The pressure distribution and thus the loads tend to decrease when the apparent wind angle is increased. The standard deviation of pressures was largest near the luff, decreasing downstream. Simultaneous time series recordings of the pressure distributions, flapping sail shapes, and forces in the sheets show a strong correlation. Flapping of spinnaker creates pressure peaks at the leading edge, increasing the aerodynamic forces dynamically by 50 to 70%. These results will also give reliable benchmark data to validate unsteady fluid structure interaction predictions from numerical simulations of downwind sails
Crossâmodal symbolic processing can elicit either an N2 or a protracted N2/N400 response
"This is the pre-peer reviewed version of the following article: Griffiths, O., Le Pelley, M. E., Jack, B. N., Luque, D., & Whitford, T. J. (2016). Cross-modal symbolic processing can elicit either an N2 or a protracted N2/N400 response. Psychophysiology, 53(7), 1044â1053. https://doi.org/10.1111/psyp.12649 , which has been published in final form at https://doi.org/10.1111/psyp.12649. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions."A crossâmodal symbolic paradigm was used to elicit EEG activity related to semantic incongruence. Twentyâfive undergraduate students viewed pairings of visual lexical cues (e.g., DOG) with congruent (50% of trials) or incongruent (50%) auditory nonlexical stimuli (animal vocalizations; e.g., sound of a dog woofing or a cat meowing). In one condition, many different pairs of congruent/incongruent stimuli were shown, whereas in a second condition only two pairs of stimuli were repeatedly shown. A typical N400âlike pattern of incongruenceârelated activity (including activity in the N2 time window) was evident in the condition using many stimuli, whereas the incongruenceârelated activity in the twoâstimuli condition was confined to differential N2âlike activity. A supplementary analysis excluded stimulus characteristics as the source of this differential activity between conditions. We found that a single individual performing a fixed task can demonstrate either a protracted N400âlike pattern of activity or a more temporally focused N2âlike pattern of activity in response to the same stimulus, which suggests that the N2 may be a precursor to the protracted N400 response
Dissociable learning processes, associative theory, and testimonial reviews: A comment on Smith and Church (2018
Smith and Church (Psychonomic Bulletin & Review, 25, 1565â1584 2018) present a âtestimonialâ review of dissociable learning processes in comparative and cognitive psychology, by which we mean they include only the portion of the available evidence that is consistent with their conclusions. For example, they conclude that learning the information-integration category-learning task with immediate feedback is implicit, but do not consider the evidence that people readily report explicit strategies in this task, nor that this task can be accommodated by accounts that make no distinction between implicit and explicit processes. They also consider some of the neuroscience relating to information-integration category learning, but do not report those aspects that are more consistent with an explicit than an implicit account. They further conclude that delay conditioning in humans is implicit, but do not report evidence that delay conditioning requires awareness; nor do they present the evidence that conditioned taste aversion, which should be explicit under their account, can be implicit. We agree with Smith and Church that it is helpful to have a clear definition of associative theory, but suggest that their definition may be unnecessarily restrictive. We propose an alternative definition of associative theory and briefly describe an experimental procedure that we think may better distinguish between associative and non-associative processes
Learned predictiveness influences rapid attentional capture:Evidence From the Dot Probe Task
Attentional theories of associative learning and categorization propose that learning about the predictiveness of a stimulus influences the amount of attention that is paid to that stimulus. Three experiments tested this idea by looking at the extent to which stimuli that had previously been experienced as predictive or nonpredictive in a categorization task were able to capture attention in a dot probe task. Consistent with certain attentional theories of learning, responses to the dot probe were faster when it appeared in a location cued by a predictive stimulus compared to a location cued by a nonpredictive stimulus. This result was obtained only with short (250-ms or 350-ms) but not long (1,000-ms) delays between onset of the stimuli and the dot probe, suggesting that the observed spatial cuing effect reflects the operation of a relatively rapid, automatic process. These findings are consistent with the approach to the relationship between attention and learning taken by the class of models exemplified by Mackintosh's (1975) theory. © 2013 American Psychological Association
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
Measuring habit formation through goal-directed response switching
Reward-learning theory views habits as stimulusâresponse links formed through extended reward training. Accordingly, animal research has shown that actions that are initially goal-directed can become habitual after operant overtraining. However, a similar demonstration is absent in human research, which poses a serious problem for translational models of behavior. We propose that response-time (RT) switch cost after operant training can be used as a new, reliable marker for the operation of the habit system in humans. Using a new method, we show that RT switch cost demonstrates the properties that would be expected of a habitual behavior: (1) it increases with overtraining; (2) it increases when rewards are larger, and (3) it increases when time pressure is added to the task, thereby hindering the competing goal-directed system. These results offer a promising new pathway for studying the operation of the habit system in humans