The effectiveness of feedback in multiple-cue probability learning

How effective are different types of feedback in helping us to learn multiple contingencies? This article attempts to resolve a paradox whereby, in comparison to simple outcome feedback, additional feedback either fails to enhance or is actually detrimental to performance in nonmetric multiple-cue probability learning (MCPL), while in contrast the majority of studies of metric MCPL reveal improvements at least with some forms of feedback. In three experiments we demonstrate that if feedback assists participants to infer cue polarity then it can in fact be effective in nonmetric MCPL. Participants appeared to use cue polarity information to adopt a linear judgement strategy, even though the environment was nonlinear. The results reconcile the paradoxical contrast between metric and nonmetric MCPL and support previous findings of people's tendency to assume linearity and additivity in probabilistic cue learning.     

Prior belief and polarity in multicue learning.

We report two experiments in which participants are trained using a multicue probability learning (MCPL) task, which attempts to simulate the acquisition of expert judgement by experience in the real world. Participants were asked to predict performance in certain occupations given a profile of personality test results with trial-by-trial outcome feedback. Only some cues were relevant, and the polarity of the cues (positive or negative predictors) was unspecified. In addition, 25% of random noise was added to the feedback to simulate real world uncertainty. The main factor of interest was that the role of prior belief (determined in a separate study of stereotypes) interfered with the learning process. Experiment 1 failed to find any influence of prior belief in the cues that were irrelevant to the criterion being trained. However, in Experiment 2 people learned to use the relevant cues better when their effect conformed with rather than conflicted with prior belief Both experiments showed strong effects of cue polarity, with positive predictors much more easily learned. The results are discussed with reference to the cognitive processes involved in MCPL and closely related tasks.     

The influence of cue unreliability on judgment in a multiple cue probability learning task

The effect of cue reliability was tested in a two-cue multiple-cue probability learning (MCPL) task. Subjects were 42 undergraduates. The cue validities were.78 and.37. Unreliability in a cue was defined as variability in multiple observations of that cue on a given trial. That variability was provided by adding random errors to the true value of the cue. One group was given consistent cues (i.e., the more valid cue was the more reliable cue), one group was given inconsistent cues, and the control group was given true scores. Cue reliability did not affect subjects' consistency or achievement, but did interact with the presence of outcome feedback. The subjective weights showed that subjects thought they weighted the more reliable cue more heavily regardless of the cue validities or their actual cue weightings. There were wide individual differences in performance, illustrating the need for an idiographic-statistical approach in studying decision making.     

The role of working memory capacity in multiple-cue probability learning

Multiple-cue probability learning (MCPL) involves learning to predict a criterion when outcome feedback is provided for multiple cues. A great deal of research suggests that working memory capacity (WMC) is involved in a wide range of tasks that draw on higher level cognitive processes. In three experiments, we examined the role of WMC in MCPL by introducing measures of working memory capacity, as well as other task manipulations. While individual differences in WMC positively predicted performance in some kinds of multiple-cue tasks, performance on other tasks was entirely unrelated to these differences. Performance on tasks that contained negative cues was correlated with working memory capacity, as well as measures of explicit knowledge obtained in the learning process. When the relevant cues predicted positively, however, WMC became irrelevant. The results are discussed in terms of controlled and automatic processes in learning and judgement.     

The role of working memory capacity in multiple-cue probability learning

Multiple-cue probability learning (MCPL) involves learning to predict a criterion when outcome feedback is provided for multiple cues. A great deal of research suggests that working memory capacity (WMC) is involved in a wide range of tasks that draw on higher level cognitive processes. In three experiments, we examined the role of WMC in MCPL by introducing measures of working memory capacity, as well as other task manipulations. While individual differences in WMC positively predicted performance in some kinds of multiple-cue tasks, performance on other tasks was entirely unrelated to these differences. Performance on tasks that contained negative cues was correlated with working memory capacity, as well as measures of explicit knowledge obtained in the learning process. When the relevant cues predicted positively, however, WMC became irrelevant. The results are discussed in terms of controlled and automatic processes in learning and judgement.     

A model of probabilistic category learning.

A new connectionist model (named RASHNL) accounts for many "irrational" phenomena found in nonmetric multiple-cue probability learning, wherein people learn to utilize a number of discrete-valued cues that are partially valid indicators of categorical outcomes. Phenomena accounted for include cue competition, effects of cue salience, utilization of configural information, decreased learning when information is introduced after a delay, and effects of base rates. Experiments 1 and 2 replicate previous experiments on cue competition and cue salience, and fits of the model provide parameter values for making qualitatively correct predictions for many other situations. The model also makes 2 new predictions, confirmed in Experiments 3 and 4. The model formalizes 3 explanatory principles: rapidly shifting attention with learned shifts, decreasing learning rates, and graded similarity in exemplar representation.     

An hypothesis generation model for judgment in nonmetric multiple-cue probability learning

The purpose of this paper is to present a two-phase hypothesis generation model to describe behavior in multiple-cue probability learning tasks with nonmetric cues. The model assumes that on each trial the subject generates two sets of hypotheses: (a) a hypothesis concerning which cue dimension (or pattern) will lead to a correct prediction on that trial and (b) a hypothesis concerning which response will be correct given the cue dimension attended to on that trial.Five-hundred-twelve subjects were assigned to 20 groups in a binary choice task involving two binary cue dimensions. Each group observed cues which differed in validity. Analysis of the data indicated that subjects attend to both cue dimensions in making judgments even when one cue has zero validity. A test of the fit of the observed data to the asymptotic response proportions predicted by the model indicated a reasonable fit.     

Cue integration with categories: Weighting acoustic cues in speech using unsupervised learning and distributional statistics

During speech perception, listeners make judgments about the phonological category of sounds by taking advantage of multiple acoustic cues for each phonological contrast. Perceptual experiments have shown that listeners weight these cues differently. How do listeners weight and combine acoustic cues to arrive at an overall estimate of the category for a speech sound? Here, we present several simulations using a mixture of Gaussians models that learn cue weights and combine cues on the basis of their distributional statistics. We show that a cue‐weighting metric in which cues receive weight as a function of their reliability at distinguishing phonological categories provides a good fit to the perceptual data obtained from human listeners, but only when these weights emerge through the dynamics of learning. These results suggest that cue weights can be readily extracted from the speech signal through unsupervised learning processes.     

Electrophysiological measures reveal the role of anterior cingulate cortex in learning from unreliable feedback

Although a growing number of studies have investigated the neural mechanisms of reinforcement learning, it remains unclear how the brain responds to feedback that is unreliable. A recent theory proposes that the reward positivity (RewP) component of the event-related brain potential (ERP) and frontal midline theta (FMT) power reflect separate feedback-related processing functions of anterior cingulate cortex (ACC). In the present study, the electroencephalogram (EEG) was recorded from participants as they engaged in a time estimation task in which feedback reliability was manipulated across conditions. After each response, they received a cue that indicated that the following feedback stimulus was 100%, 75%, or 50% reliable. The results showed that participants’ time estimates adjusted linearly according to the feedback reliability. Moreover, presentation of the cue indicating 100% reliability elicited a larger RewP-like ERP component than the other cues did, and feedback presentation elicited a RewP of approximately equal amplitude for all of the three reliability conditions. By contrast, FMT power elicited by negative feedback decreased linearly from the 100% condition to 75% and 50% condition, and only FMT power predicted behavioral adjustments on the following trials. In addition, an analysis of Beta power and cross-frequency coupling (CFC) of Beta power with FMT phase suggested that Beta-FMT communication modulated motor areas for the purpose of adjusting behavior. We interpreted these findings in terms of the hierarchical reinforcement learning account of ACC, in which the RewP and FMT are proposed to reflect reward processing and control functions of ACC, respectively.     

Failure of additivity in bisection of length

Subjects were intructed to select one rod to lie halfway in length between two given rods. These bisection instructions imply an additive model in the subjective metric. However, the data were inherently nonadditive; the length of the bisector could be an increasing or a decreasing function of the length of one given rod, depending on the length of the other given rod. A convexity analysis and a nonmetric analysis both showed that no monotone transformation could make the data additive. The bisection problem is used to contrast the axiomatic and functional approaches to measurement theory.     

Terminal Feedback Outperforms Concurrent Visual,Auditory, and Haptic Feedback in Learning a Complex Rowing-Type Task

Augmented feedback, provided by coaches or displays, is a well-established strategy to accelerate motor learning. Frequent terminal feedback and concurrent feedback have been shown to be detrimental for simple motor task learning but supportive for complex motor task learning. However, conclusions on optimal feedback strategies have been mainly drawn from studies on artificial laboratory tasks with visual feedback only. Therefore, the authors compared the effectiveness of learning a complex, 3-dimensional rowing-type task with either concurrent visual, auditory, or haptic feedback to self-controlled terminal visual feedback. Results revealed that terminal visual feedback was most effective because it emphasized the internalization of task-relevant aspects. In contrast, concurrent feedback fostered the correction of task-irrelevant errors, which hindered learning. The concurrent visual and haptic feedback group performed much better during training with the feedback than in nonfeedback trials. Auditory feedback based on sonification of the movement error was not practical for training the 3-dimensional movement for most participants. Concurrent multimodal feedback in combination with terminal feedback may be most effective, especially if the feedback strategy is adapted to individual preferences and skill level.     

Explicit and implicit processes in multicue judgment

In two experiments, a multicue probability learning task was used to train participants in relating judgments to a criterion, on the basis of several cues that could or could not be relevant. The outcome feedback had 25% added noise to simulate real-world experience-based learning. Judgmental strategies acquired were measured by individual multiple linear regression analyses of a test phase (with no feedback) and were compared with self-ratings of cue relevance. In a third experiment, participants were instructed explicitly on cue relevance, with no training phase. The pattern of results suggested that both implicit and explicit cognitive processes influenced judgments and that they may have been sensitive to different task manipulations in the learning phase. On more complex tasks, despite weak explicit learning, explicit processes continued to influence judgments, producing a decrement in performance. These findings explain why studies of expert judgment often show only moderate levels of self-insight, since people have only partial access to the processes determining their judgments.     

Errors committed with high confidence are hypercorrected.

The relation between people's confidence in the accuracy of an erroneous response and their later performance was investigated. Most models of human memory suggest that the higher a person's confidence, the stronger the item (in the context of the eliciting cue) that is retrieved from memory. In recall, stronger associates to a cue interfere with competing associates more than do weaker associates. This state of affairs implies that errors endorsed with high, rather than low, confidence should be more difficult to correct by learning the correct response feedback. In contrast to the authors' expectations, highly confident errors were the most likely to be corrected in a subsequent retest. Participants nearly always endorsed the correct response in cases in which both the correct response and the original erroneous response were generated at retest, suggesting that people possess a refined metacognitive ability to know what is correct and incorrect.     

Does test-enhanced learning transfer for triple associates?

Test-enhanced learning and transfer for triple-associate word stimuli was assessed in three experiments. In each experiment, training and final-test trials involved the presentation of two words per triple associate (triplet), with the third word having to be retrieved. In agreement with the prior literature on different stimuli, training through testing with feedback yielded markedly better final-test performance than did restudy. However, in contrast to the positive transfer reported for paired associate stimuli, minimal or no positive transfer was observed, relative to a restudy control, from a trained cue combination (e.g., A, B, ?) to other cue combinations from the same triplet that required a different response (e.g., B, C, ?). That result also held when two unique cue combinations per triplet were tested during training, and for triplets with low and high average associative strengths. Supplementary analyses provided insight into the overall transfer effect: An incorrect response during training appears to yield positive transfer relative to restudy, whereas a correct response appears to yield no, or even negative, transfer. Cross-experiment analyses indicated that test-enhanced learning is not diminished when two or three cue combinations are presented during training. Thus, even though learning through testing is highly specific, testing on all possible stimulus–response combinations remains the most efficient strategy for the learning of triple associates.     

基本特征水平的知觉学习与注意的作用

在基本特征水平的知觉学习的研究中是否存在注意与反馈的作用,是一直存在着争论的问题。该研究通过线索不同的有效性来控制注意的分配,探讨了在基本特征水平的知觉学习中注意与反馈的作用,共进行了两个实验,实验一采用内源和外源性线索影响注意分配,探讨基本特征刺激加工过程中注意的作用;实验二对基本特征刺激的知觉学习过程的特性进行研究。学习和探测任务都是让被试从所呈现的刺激中寻找靶子英文字母L。结果发现：在基本特征水平的知觉学习中存在有注意的作用;其学习过程存在反馈的作用。     

On scales of sensation: Prolegomena to any future psychophysics that will be able to come forth as science

Sensory scales fall into two classes. Type I scales of sensory intensity can be approximated by metric scaling procedures (magnitude estimation, magnitude production) and nonmetric procedures (conjoint measurement); Type I scales are supported by theoretical consideration of sensory processes. Type II scales of sensory dissimilarity can be approximated by metric scaling procedures (category rating, interval estimation, equisection) and nonmetric procedures (analysis of proximities). The psychophysical functions that relate Type I and Type II scales to their corresponding physical scales are in both cases power functions, but the exponents that govern Type I functions are typically about twice as large. Both Type I scales of sensory intensity and Type II scales of sensory dissimilarity are meaningful measures of perceptual experience, but they are measures of different aspects of perception. The duality of sensory scales helps to explain some apparent contradictions among divergent attempts to validate scales of sensation.     

Transient covert attention does alter appearance: a reply to Schneider (2006)

We recently demonstrated that transient covert attention increases the apparent contrast of a stimulus (Carrasco, Ling, & Read, 2004). Schneider (2006) proposes that the observed increase in apparent contrast is largely due to sensory interactions occurring between the precue a nd stimulus,rather than to attention. Specifically, hereports that cuing effects only occur at contrasts ne ar detection threshold, and that there a re confounding sensoryinteractions between the cue and stimulus at suprathreshold detection contrasts. Our response is twofold. First, we outline the key methodological differences between our original study and Schneider's that are likely to account for the different results, and explain how we had ruled out the sensory interaction explanation of the cue. Second, we directly test the prediction put forth by Schneider. If the effects were due to sensory interactions, reversing the luminance polarity of the precue in our paradigm should lead to differential cuing effects. We replicate one of the experiments of our original study and add a condition in which the cue luminance is either black or white. Our results replicated our previous findings-they showed an increase in apparent contrast to a high-contrast stimulus when it was precued. Moreover, we found that the black cue and the white cue had the same effect, thus ruling out the alternative explanation proposed by Schneider. Transient attention does alter contrast appearance.     

Sensitivity to attachment, alignment, and contrast polarity variation in local perceptual grouping

A number of leading theories (e.g., Grossberg & Mingolla, 1985; Kellman & Shipley, 1991; Rensink & Enns, 1995) commonly assume that perceptual grouping by contour alignment occurs preattentively across reversing contrast polarity elements. We examined this notion in seven visual search experiments. We found that only grouping by attachment supported preattentive visual search and that grouping by contour alignment required attention in order to operate. Both attachment grouping and grouping by contour alignment were sensitive to contrast reversals. Further results showed that contour alignment was a strong grouping cue only among elements with the same contrast sign but that it did not facilitate grouping across reversing contrast. These results suggest that grouping by contour alignment operates only on inputs of consistent contrast polarity.     

Integration of disparity and velocity information for haptic and perceptual judgments of object depth

Do reach-to-grasp (prehension) movements require a metric representation of three-dimensional (3D) layouts and objects? We propose a model relying only on direct sensory information to account for the planning and execution of prehension movements in the absence of haptic feedback and when the hand is not visible. In the present investigation, we isolate relative motion and binocular disparity information from other depth cues and we study their efficacy for reach-to-grasp movements and visual judgments. We show that (i) the amplitude of the grasp increases when relative motion is added to binocular disparity information, even if depth from disparity information is already veridical, and (ii) similar distortions of derived depth are found for haptic tasks and perceptual judgments. With a quantitative test, we demonstrate that our results are consistent with the Intrinsic Constraint model and do not require 3D metric inferences (Domini, Caudek, & Tassinari, 2006). By contrast, the linear cue integration model (Landy, Maloney, Johnston, & Young, 1995) cannot explain the present results, even if the flatness cues are taken into account.     

Multidimensional scaling of form: A psychophysical analysis

Both metric and nonmetric multidimensional scaling methods were used to analyze similarity estimates when random polygons were used as stimulus patterns. Three dimensions, dispersion, jaggedness, and elongation were obtained with both analyses and were related to physical measures of the patterns.