Search

In young children, learning the form and meaning of new words is a basic component of language development. What aspects of a child's experience facilitate that word learning? One aspect [...], Purpose: Perceptual learning and production practice are basic mechanisms that children depend on to acquire adult levels of speech accuracy. In this study, we examined perceptual learning and production practice as they contributed to changes in speech accuracy in 3- and 4-year-old children. Our primary focus was manipulating the order of perceptual learning and production practice to better understand when and how these learning mechanisms interact. Method: Sixty-five typically developing children between the ages of 3 and 4 years were included in the study. Children were asked to produce CVCCVC (C = consonant, V = vowel) nonwords like /bozjem/ and /tAvtFep/ that were described as the names of make-believe animals. All children completed two separate experimental blocks: a control block in which participants heard each nonword once and repeated it, and a test block in which the perceptual input frequency of each nonword varied between 1 and 10. Half of the participants completed a control-test order; half completed a test-control order. Results: Greater accuracy was observed for nonwords produced in the second experimental block, reflecting a production practice effect. Perceptual learning resulted in greater accuracy during the test for nonwords that participants heard 3 times or more. However, perceptual learning did not carry over to control productions in the test-control design, suggesting that it reflects a kind of temporary priming. Finally, a post hoc analysis suggested that the size of the production practice effect depended on the age of acquisition of the consonants that comprised the nonwords. Conclusions: The study provides new details about how perceptual learning and production practice interact with each other and with phonological aspects of the nonwords, resulting in complex effects on speech accuracy and learning of form-referent pairs. These findings may ultimately help speech-language pathologists maximize their clients' improvement in therapy. Supplemental Material: https://doi.org/10.23641/asha. 12971411

It is already well established from behavioral studies that both adults (e.g., Ari-Even Roth, Amir, Alaluf, Buchsenspanner, & Kishon-Rabin, 2003; Ari-Even Roth, Kishon-Rabin, & Hildesheimer, 2001; Banai & Lavner, 2014; [...], Purpose: The purpose of this study is to investigate the role of external feedback in auditory perceptual learning of school-age children as compared with that of adults. Method: Forty-eight children (7-9 years of age) and 64 adults (20-35 years of age) conducted a training session using an auditory frequency discrimination (difference limen for frequency) task, with external feedback (EF) provided for half of them. Results: Data supported the following findings: (a) Children learned the difference limen for frequency task only when EF was provided. (b) The ability of the children to benefit from EF was associated with better cognitive skills. (c) Adults showed significant learning whether EF was provided or not. (d) In children, within-session learning following training was dependent on the provision of feedback, whereas between-sessions learning occurred irrespective of feedback. Conclusions: EF was found beneficial for auditory skill learning of 7-9-year-old children but not for young adults. The data support the supervised Hebbian model for auditory skill learning, suggesting combined bottom-up internal neural feedback controlled by top-down monitoring. In the case of immature executive functions, EF enhanced auditory skill learning. This study has implications for the design of training protocols in the auditory modality for different age groups, as well as for special populations.

People are remarkably good at comprehending speech, even though the acoustic realization of a given utterance can vary markedly. This variability can arise from environmental factors (e.g., background noise and [...], Purpose: We investigated whether perceptual learning of noise-vocoded (NV) speech is specific to a particular talker or accent. Method: Four groups of listeners (n = 18 per group) were first trained by listening to 20 NV sentences that had been recorded by a talker with either the same native accent as the listeners or a different regional accent. They then heard 20 novel NV sentences from either the native- or nonnative-accented talker (test), in a 2 x 2 (Training Talker per Accent x Test Talker per Accent) design. Results: Word-report scores at test for participants trained and tested with the same (native- or nonnative-accented) talker did not differ from those for participants trained with 1 talker per accent and tested on another. Conclusions: Learning of NV speech generalized completely between talkers. Two additional experiments confirmed this result. Thus, when listeners are trained to understand NV speech, they are not learning talker- or accent-specific features but instead are learning how to use the information available in the degraded signal. The results suggest that people with cochlear implants, who experience spectrally degraded speech, may not be too disadvantaged if they learn to understand speech through their implant by listening primarily to just 1 other talker, such as a spouse.

Listeners regularly encounter unexpected variation in speech, to which they must adapt in order to successfully perceive the signal. Various causes for these idiosyncrasies include accent and dialect differences, speech [...], Purpose: This study examined whether older adults remain perceptually flexible when presented with ambiguities in speech in the absence of lexically disambiguating information. We expected older adults to show less perceptual learning when top-down information was not available. We also investigated whether individual differences in executive function predicted perceptual learning in older and younger adults. Method: Younger (n = 31) and older adults (n = 27) completed 2 perceptual learning tasks composed of a pretest, exposure, and posttest phase. Both learning tasks exposed participants to clear and ambiguous speech tokens, but crucially, the lexically guided learning task provided disambiguating lexical information whereas the distributional learning task did not. Participants also performed several cognitive tasks to investigate individual differences in working memory, vocabulary, and attention-switching control. Results: We found that perceptual learning is maintained in older adults, but that learning may be stronger in contexts where top-down information is available. Receptive vocabulary scores predicted learning across both age groups and in both learning tasks. Conclusions: Implicit learning is maintained with age across different learning conditions but remains stronger when lexically biasing information is available. We find that receptive vocabulary is relevant for learning in both types of learning tasks, suggesting the importance of vocabulary knowledge for adapting to ambiguities in speech.

Perceptual systems must learn to explore and to use the resulting information to hone performance. Optimal performance depends on using information available at many time scales, from the near instantaneous values of variables underlying perception (i.e., detection), to longer term information about appropriate scaling (i.e., calibration), to yet longer term information guiding variable use (i.e., attunement). Fractal fluctuations in explorations would entail fluctuation at all time scales, allowing perceptual systems a flexible way to detect information at all time scales. We tested whether perceptual learning in dynamic touch is related to the fractality of wielding behaviors. A reanalysis of wielding behaviors from Arzamarski, Isenhower, Kay, Turvey, and Michael s (2010) revealed that exploratory movements were fractal and that a fractal-scaling exponent predicts individual differences in haptic judgments. Keywords: perceptual learning, dynamic touch, haptic perception, fractal, scaling exponent DOI: 10.1037/a0019219

Perceptual learning, improvement in perceptual skill with practice, can improve both accuracy and consistency of perceptual reports. Regression statistics can quantify ongoing calibration of perceptible scalar properties (i.e., improvements in accuracy and consistency) because, ideally, actual and perceived values are linearly related. Changes in variance accounted for ([r.sup.2]) track changes in consistency, and changes in both slope and intercept track changes in accuracy. Conjoint changes in all three regression statistics, obscured in separate plots, can be seen simultaneously in a perceptual calibration state space diagram, with the regression statistics as axes, in which an attractor ([r.sup.2] = 1.00, slope = 1.00, intercept = 0.00) represents optimal performance. Decreases in the distance between the attractor and successive points in the state space, each representing perceptual performance, quantify perceptual learning; that distance is a perceptual calibration index. To show the utility of the perceptual calibration index, we illustrate its use in an experiment on wielding hand-held objects.

How do infants learn to perceive the backs of objects that they see only from a limited viewpoint? Infants' 3-dimensional object completion abilities emerge in conjunction with developing motor skills--independent sitting and visual--manual exploration. Infants at 4.5 to 7.5 months of age (n = 28) were habituated to a limited-view object and tested with volumetrically complete and incomplete (hollow) versions of the same object. Parents reported infants' sitting experience, and infants' visual--manual exploration of objects was observed in a structured play session. Infants' self-sitting experience and visual--manual exploratory skills predicted looking at the novel, incomplete object on the habituation task. Further analyses revealed that self-sitting facilitated infants' visual inspection of objects while they manipulated them. The results are framed within a developmental systems approach, wherein infants' sitting skill, multimodal object exploration, and object knowledge are linked in developmental time. Keywords: perceptual development, three-dimensional object perception, exploration, object manipulation, sitting DOI: 10.1037/a0014618

Improvements in performance on many perceptual skills can occur with only a single training session. Of interest here is what aspects of the training experience are being learned during this brief exposure. Although there is considerable evidence that learning associated with specific feature values of the stimulus used in training (stimulus learning) contributes to these rapid improvements, there has been little direct investigation of the possibility that other types of learning do so as well. Here the authors show that not only stimulus learning but also learning of more general aspects of the training experience (procedure learning) contributed to rapid improvements in performance on interaural time difference discrimination. However, practice on the type of judgment to be made did not appear to aid performance (no task learning). These results are consistent with physiological reports that different neural mechanisms are engaged at different time points during even a brief training session, and imply that the circuits that are engaged and likely modified vary in the degree of their selectivity to the target condition. Such changes presumably enable further learning. Keywords: perceptual learning, procedural learning, human, auditory, interaural time difference

The present research investigated the effects of physical context change and perceptual learning on generalization. In a video game, participants learned to suppress their mouse-clicking behavior in the presence of one stimulus (AX). Generalization was observed between the AX stimulus and another stimulus (BX) that was designed to be similar. When testing was conducted in a context different from that in which AX was used in training, responding to AX was attenuated, and responding to BX was enhanced. That is, the generalization gradient flattened. The latter effect was only evident in groups for which generalization had been reduced through a preexposure manipulation believed to produce perceptual learning. Experiment 2 demonstrated that the increase in generalization observed in the first experiment was due to the context change between the preexposure and test rather than to a change between the conditioning and test contexts. Implications for flattening generalization gradients and mechanisms of perceptual learning are discussed.

In Experiment la, participants were exposed, over a series of trials, to separate presentations of 2 similar checkerboard stimuli, AX and BX (where X represents a common background). In one group, AX and BX were presented on alternating trials (intermixed), in another, they were presented in separate blocks of trials (blocked). The intermixed group performed to a higher standard than the blocked group on a same--different test. A superiority of intermixed over blocked exposure was also evident in a within-subject design (Experiment lb) and when the test required discrimination between a preexposed stimulus and the background (e.g., AX vs. X), even if the background changed between preexposure and test (AY vs. Y) (Experiment 2). In Experiment 3, the intermixed/blocked effect was observed when, in preexposure, stimulus presentations were alternated with the background alone (e.g., AX/X). This suggests that the perceptual learning effect is not the consequence of inhibitory associations between unique features but to increased salience of those features. Experiment 4 confirmed this finding and also ruled out an account of the effect in terms of trial spacing. Keywords: discrimination, preexposure, perceptual learning, inhibition, salience

G. P. Bingham, R. C. Schmidt, and L. D. Rosenblum (1989) found that, by hefting objects of different sizes and weights, people could choose the optimal weight in each size for throwing to a maximum distance. In Experiment 1, the authors replicated this result. G. P. Bingham et al. hypothesized that hefting is a smart mechanism that allows objects to be perceived in the context of throwing dynamics. This hypothesis entails 2 assumptions. First, hefting by hand is required for information about throwing by hand. The authors tested and confirmed this in Experiments 2 and 3. Second, optimal objects are determined by the dynamics of throwing. In Experiment 4, the authors tested this by measuring throwing release angles and using them with mean thrown distances from Experiment 1 and object sizes and weights to simulate projectile motion and recover release velocities. The results showed that only weight, not size, affects throwing. This failed to provide evidence supporting the particular smart mechanism hypothesis of G. P. Bingham et al. Because the affordance relation is determined in part by the dynamics of projectile motion, the results imply that the affordance is learned from knowledge of results of throwing. Keywords: afffordances, smart mechanism, haptic perception, dynamics, perceptual learning

A dynamic touch paradigm in which participants judged the lengths of rods and pipes was used to test the D. M. Jacobs and C. F. Michaels (2007) theory of perceptual learning. The theory portrays perception as the exploitation of a locus on an information manifold and learning as continuous movement across that manifold to a new locus, as guided by information available in feedback. The information manifold was defined as a 1-dimensional space of inertial variables. To encourage maximal learning, a 2-step procedure was used in each of 2 experiments. Each step comprised a pretest to identify the starting locus on the information manifold, a practice phase in which feedback specifying the optimal locus was given, and a posttest in which the ending locus on the manifold was identified. In the 2nd step, a different feedback variable specified a different optimum. In both experiments, participants, who sometimes began at different loci, showed the predicted movement toward the optimum in each phase. Whereas previous applications of the theory posit the existence of information-for-learning without identifying a candidate variable, such a candidate is identified. Keywords: perceptual learning, direct perception, ecological psychology, dynamic touch, haptics

In three experiments, rats were given concurrent exposure to a compound flavor (AX) and to one of the elements of the compound (X). The perceptual effectiveness of A was then assessed by a test involving generalization of a conditioned aversion. Comparison was made with a preexposure procedure in which the compound and the common element were presented on separate trials, either in alternation or in separate blocks of trials. The effectiveness of the unique cue was less after blocked preexposure than after either of the other procedures; concurrent preexposure did not produce a greater effect than did alternating preexposure. These results challenge the suggestion that concurrent preexposure engages a special comparison process that will facilitate this form of perceptual learning.

During sustained viewing of an ambiguous stimulus, an individual's perceptual experience will generally switch between the different possible alternatives rather than stay fixed on one interpretation (perceptual rivalry). Here, we measured pupil diameter while subjects viewed different ambiguous visual and auditory stimuli. For all stimuli tested, pupil diameter increased just before the reported perceptual switch and the relative amount of dilation before this switch was a significant predictor of the subsequent duration of perceptual stability. These results could not be explained by blink or eye-movement effects, the motor response or stimulus driven changes in retinal input. Because pupil dilation reflects levels of norepinephrine (NE) released from the locus coeruleus (LC), we interpret these results as suggestive that the LC-NE complex may play the same role in perceptual selection as in behavioral decision making. attention | norepinephrine | vision | decision making

A robust finding in humans and animals is that intermixed exposure to 2 similar stimuli (AX/BX) results in better discriminability of those stimuli on test than does exposure to 2 equally similar stimuli in 2 separate blocks (CX_DX)--the intermixed--blocked effect. This intermixed-blocked effect may be an example of the superiority of spaced over massed practice; in the intermixed, but not the blocked exposure regime, each presentation of a given stimulus (e.g., AX) is separated from the next by the presentation of its partner (BX). Two experiments with human participants replicated the intermixed--blocked effect and showed that the effect was not due to the spacing of exposure trials. A mechanism for the intermixed--blocked effect is proposed, which combines theories from associative learning and memory. Keywords: perceptual learning, spaced practice, memory, discrimination

The effect of multidimensional perceptual-cognitive skills training including situational awareness, anticipation and decision making on the performance of older adult tennis players on-court is presented. Results provide evidence that perceptual-cognitive skills can be trained in aged individual.

Human participants received unsupervised exposure to difficult-to-discriminate stimuli (e.g., A and A'), created with a morphing procedure from photographs of faces, before learning a discrimination between them. Experiments 1 and 2 demonstrated that prior exposure enhanced later discrimination and that intermixed exposure (A, A', A, A' ...) resulted in better subsequent discrimination than blocked exposure (B, B, ... B', B' ...). Experiments 3 and 4 showed that simultaneous exposure to 2 similar stimuli facilitated the later acquisition of both a simultaneous and a successive discrimination, and this effect was observed even though simultaneous exposure to 2 stimuli fostered the development of an excitatory association between them (Experiment 5). The findings of Experiments 1 and 2 revealed a perceptual learning effect with pictures of faces, and the findings of Experiments 3-5 ate difficult to reconcile with associative analyses of perceptual learning. Keywords: perceptual learning, humans, unsupervised, associative, faces

Rats received habituation to either 2 compound flavors (AX and BY; the activation group) or a compound and an element alone (AX and Y; the habituation group). They also received additional presentations of Y alone either after (Experiment 1) or intermixed (Experiment 2) with habituation. In the habituation group, A had undergone habituation whereas B had not; in the activation group, both A and B had undergone habituation, but presenting Y alone should result in associative activation of B and that, according to G. Hall (2003), should increase B's efficacy. A supplementary experiment demonstrated that the presentation of Y does activate a representation of B. In both experiments, an aversion was established to AB, and subsequently the habituation group showed a greater aversion to B than to A. However, in neither experiment was there any indication that the activation group showed a greater aversion to B than to A. These results are inconsistent with the suggestion that the associative activation of a stimulus representation in the absence of the stimulus reverses the effects of habituation training. Keywords: habituation, association, salience modification, perceptual learning

In 4 experiments, rats were given intermixed or blocked preexposure to an array of landmarks that subsequently defined the location of a hidden goal in a Morris pool task. Previous research has shown that intermixed preexposure to pairs of adjacent landmarks retards learning whereas preexposure to individual landmarks facilitates subsequent learning (J. Prados, V. D. Chamizo, & N. J. Mackintosh, 1999). Accordingly, in Experiment 1, intermixed and blocked preexposure to pairs of adjacent landmarks was found to retard learning. In Experiment 2, however, a scheduling effect was found: Rats given intermixed preexposure to the individual landmarks learned faster than rats given blocked or no preexposure. Experiment 3 showed that intermixed (but not blocked) preexposure to pairs of landmarks resulted in a facilitatory effect when preexposure and test were carried out in different contexts. Experiment 4 replicated within a single experiment the main results observed in Experiments 1 and 3. This pattern of results suggests that intermixed preexposure engages learning processes other than latent inhibition that facilitate subsequent learning of the navigation task. Keywords: Morris navigation task, latent inhibition, perceptual learning, associative inhibition, salience modulation

Olfactory memory is especially persistent. The current study explored whether this applies to a form of perceptual learning, in which experience of an odor mixture results in greater judged similarity between its elements. Experiment 1A contrasted 2 forms of interference procedure, 'compound' (mixture AW, followed by presentation of new mixtures each containing 1 of its elements, AX and DW) and 'elemental' (mixture CY, followed by presentation of its elements C and Y) against a nonexposed control. Learning was evident in both interference conditions to the same degree, relative to the control. Experiment 1B established that the interference conditions did not significantly differ from uninterfered paired controls. Experiment 2 compared the 'compound' procedure with 2 exposed control conditions and assessed whether participants had acquired the interfering mixtures too (AX and DY). Learning was evident in the 'compound' treated pair (AW) and also for the mixtures AX and DW that made up the interfering compounds. These results are problematic for configural explanations and a new formulation is suggested., The claim that human olfactory cognition is qualitatively different from other sensory domains has been made frequently and relies to no small extent upon the finding that odor memory is [...]

A test of the predicted interaction between within-category discontinuity and verbal rule complexity on information-integration and rule-based category learning was conducted. Within-category discontinuity adversely affected information-integration category learning but not rule-based category learning. Model-based analyses suggested that some information-integration participants improved performance by recruiting more 'units' in the discontinuous condition. Verbal rule complexity adversely affected rule-based category learning but not information-integration category learning. Model-based analyses suggested that the rule based effect was on both decision criterion learning and variability in decision criterion placement. These results suggest that within-category discontinuity and decision rule complexity differentially impact information-integration and rule-based category learning and provide information regarding the detailed processing characteristics of these two proposed category learning systems. Keywords: multiple systems, classification learning, category learning, procedural-based learning, rule complexity DOI: 10.1037/0278-7393.33.1.197

This study tested whether 4-month-old infants respond primarily to objects' physical or retinal image sizes. In the study's main experiment, infants were habituated to either a 6-cm-diameter disk at a distance of 18 cm or a 10-cm disk at 50 cm. They were then given 2 test trials in which the 6- and 10-cm disks were presented side by side at a distance of 30 cm. For each infant, one test object had a novel physical size but a familiar retinal image size, and the other had a familiar physical size but a novel retinal image size. The infants exhibited a significant looking preference for the object that had a novel physical size. A preliminary experiment found that 4-month-olds' looking preferences are based on novelty, not familiarity, under the conditions of this study. Given this finding, the results suggest that 4-month-old infants attend and respond primarily to physical size, not to retinal image size. Keywords: size constancy, size perception, object perception, infancy, perceptual development

A perceptual learning experiment provides evidence that the mental lexicon cannot consist solely of detailed acoustic traces of recognition episodes. In a training lexical decision phase, listeners heard an ambiguous [f-s] fricative sound, replacing either If] or [s] in words. In a test phase, listeners then made lexical decisions to visual targets following auditory primes. Critical materials were minimal pairs that could be a word with either [f] or [s] (cf. English knife-nice), none of which had been heard in training. Listeners interpreted the minimal pair words differently in the second phase according to the training received in the first phase. Therefore, lexically mediated retuning of phoneme perception not only influences categorical decisions about fricatives (Norris, McQueen, & Cutler, 2003), but also benefits recognition of words outside the training set. The observed generalization across words suggests that this retuning occurs prelexically. Therefore, lexical processing involves sublexical phonological abstraction, not only accumulation of acoustic episodes. Keywords: Speech perception; Perceptual learning; Phonological abstraction; Episodic models; Spoken-word recognition

Piriform cortical circuits are hypothesized to form perceptions from responses to specific odorant features, but the anterior piriform cortex (aPCX) and posterior piriform cortex (pPCX) differ markedly in their anatomical organization, differences that could lead to distinct roles in odor encoding. Here, we tested whether experience with a complex odorant mixture would modify encoding of the mixture and its components in aPCX and pPCX. Rats were exposed to an odorant mixture and its components in a go/no-go rewarded odor discrimination task. After reaching behavioral performance criterion, single-unit recordings were made from the aPCX and pPCX in these rats and in odor-naive, control, urethane-anesthetized rats. After odor experience, aPCX neurons were more narrowly tuned to the test odorants, and there was a decorrelation in aPCX population responses to the mixture and its components, suggesting a more distinct encoding of the familiar mixture from its components. In contrast, pPCX neurons were more broadly tuned to the familiar odorants, and pPCX population responses to the mixture and its components became more highly correlated, suggesting a pPCX encoding of similarity between familiar stimuli. The results suggest aPCX and pPCX play different roles in the processing of familiar odors and are consistent with an experience-dependent encoding (perceptual learning) of synthetic odorant identity in aPCX and an experience-dependent encoding of odor similarity or odor quality in pPCX. memory | olfactory discrimination | perceptual learning | odorant mixture | odor encoding

Participants learned to classify seemingly arbitrary words into categories that also corresponded to ad hoc categories (see, e.g., Barsalou, 1983). By adapting experimental mechanisms previously used to study knowledge restructuring in perceptual categorization, we provide a novel account of how experimental and preexperimental knowledge interact. Participants were told of the existence of the ad hoc categories either at the beginning or the end of training. When the ad hoc labels were revealed at the end of training, participants switched from categorization based on experimental learning to categorization based on preexperimental knowledge in some, but not all, circumstances. Important mediators of the extent of that switch were the amount of performance error experienced during prior learning and whether or not prior knowledge was in conflict with experimental learning. We present a computational model of the trade-off between preexperimental knowledge and experimental learning that accounts for the main results.

This article builds a bridge between research on regulatory focus in motivation and classification learning. It tests the hypothesis that a fit between the situational regulatory focus and the reward structure of the task leads to greater cognitive flexibility than does a mismatch between situational focus and the reward structure and that the fit between the regulatory-focus-induced processing characteristics and the nature of the environment influences performance. In Experiment 1, we used a classification task for which cognitive flexibility should be advantageous and examined both gains (Experiment 1A) and losses (Experiment 1B) reward structures. In Experiments 2 and 3, we used a classification task for which cognitive flexibility should be disadvantageous. In Experiment 2, we used a gains reward structure, and in Experiment 3, we used a losses reward structure. As was predicted, when cognitive flexibility was advantageous, the participants in a regulatory fit showed faster learning and more quickly shifted toward the optimal response strategy. Also as was predicted, when cognitive flexibility was disadvantageous, the participants in a regulatory mismatch showed faster learning and more quickly shifted toward the optimal response strategy. Implications for current theories of motivation and classification learning are discussed.

Prism exposure produces 2 kinds of adaptive response. Recalibration is ordinary strategic remapping of spatially coded movement commands to rapidly reduce performance error. Realignment is the extraordinary process of transforming spatial maps to bring the origins of coordinate systems into correspondence. Realignment occurs when spatial discordance signals noncorrespondence between spatial maps. In Experiment 1, generalization of recalibration aftereffects from prism exposure to postexposure depended upon the similarity of target pointing limb postures. Realignment aftereffects generalized to the spatial maps involved in exposure. In Experiment 2, the 2 kinds of aftereffects were measured for 3 test positions, one of which was the exposure training position. Recalibration aftereffects generalized nonlinearly, while realignment aftereffects generalized linearly, replicating Bedford (1989, 1993a) using a more familiar prism adaptation paradigm. Recalibration and realignment require methods for distinguishing their relative contribution to prism adaptation. Keywords: cognitive learning, coordination, motor control, perceptual learning, recalibration, realignment, spatial mapping

Recent visual marking studies have shown that the carry-over of distractor inhibition can impair the ability of singletons to capture attention if the singleton and distractors share features. The current study extends this finding to first-order motion targets and distractors, clearly separated in time by a visual cue (the letter X). Target motion discrimination was significantly impaired, a result attributed to the carry-over of distractor inhibition. Increasing the difficulty of cue detection increased the motion target impairment, as distractor inhibition is thought to increase under demanding (high load) conditions in order to maximize selection efficiency. The apparent conflict with studies reporting reduced distractor inhibition under high load conditions was resolved by distinguishing between the effects of 'cognitive' and 'perceptual' load. Keywords: inhibition, perceptual load, visual marking, motion

In two experiments, we examined how preexposure to discriminative stimuli and introduction of a 21-day retention interval affected the latent inhibition (LI) and perceptual learning (PL) of rats in a choice-maze discrimination task. Experimental groups were preexposed to three wall patterns, one in each of three arms of a maze. Control groups were preexposed only to white arms. PL groups were trained to discriminate A versus B, and LI groups, to discriminate A or B versus C. The A and B patterns shared many elements not shared with the C pattern. In Experiment 1, both at the end of training and after the subsequent retention interval, the PL groups performed better than controls, whereas the LI groups performed worse. In Experiment 2, inserting the 21-day retention interval between preexposure and discrimination training disrupted final measures of LI but not PL performance. Implications for current concepts of PL and LI are discussed.

Judgments of learning (JOLs) underestimate the increase in recall that occurs with repeated study (the underconfidence-with-practice effect; UWP). The authors explore an account in terms of a foresight bias in which JOLs are inflated when the to-be-recalled target highlights aspects of the cue that are not transparent when the cue appears alone and the tendency of practice to alleviate bias by providing learners with cues pertinent to recall. In 3 experiments the UWP effect was strongest for items that induce a foresight bias, but delaying JOLs reduced the debiasing effects of practice, thereby moderating the UWP effect. This occurred when delayed JOLs were prompted by the cue alone (like during testing), not when prompted by the cue-target pair (like during study). Keywords: judgments of learning, underconfidence, debiasing, foresight bias

One of the most important reasons to investigate human metacognition is its role in directing how people study. However, limited evidence exists that metacognitively guided study benefits learning. Three experiments are presented that provide evidence for this link. In Experiment 1, participants' learning was enhanced when they were allowed to control what they studied. Experiments 2a-d replicated this finding and showed contributions of self-regulated study to learning. Experiments 3a and 3b showed that, when forced to choose among items they did not know, participants chose the easiest items and benefited from doing so, providing evidence for the link between metacognitive monitoring/control and learning, and supporting the region of proximal learning model of study-time allocation. Keywords: metacognition, study-time allocation, region of proximal learning, education, memory

Four experiments tested context switch effects on acquisition and extinction in human predictive learning. A context switch impaired probability judgments about a cue-outcome relationship when the cue was trained in a context in which a different cue underwent extinction. The context switch also impaired judgments about a cue trained in a context different from the extinction context, whenever this training was concurrent with extinction of another cue. After extinction, new cue--outcome relationships learned, even in a different task, became context specific. Moreover, renewal was consistently observed. It is suggested that context switch effects result from a process by which ambiguity leads participants to attend to the contexts. Keywords: context switch effects, extinction, attention, human predictive learning, renewal, retrieval theory of forgetting

Rats were given intermixed preexposure to the compound flavors AX and BX and to the compound CX in a separate block of trials (4 presentations of each compound). In Experiment 1, rats showed less generalization of conditioned aversion from AX to BX than from CX to BX, a perceptual learning effect. Experiment 2 showed that the formation of an excitatory association proceeded more readily between A and B than between C and B, suggesting that intermixed preexposure maintains the effective salience of A and B and does not establish inhibition between them, a process that would require prolonged preexposure. According to this analysis, salience modulation and associative inhibition may contribute to perceptual learning at different stages of preexposure. Keywords: perceptual learning, salience modulation, inhibition

Perceptual learning in humans was examined in 2 experiments. In Experiment 1, participants received intermixed exposure to 2 similar compounds (AX, BX, AX, BX, ...) and blocked exposure to a 2nd pair of similar compounds (CY, CY, ..., DY, DY, ...). Aversions established to AX and CY generalized less to BX than to DY. In Experiment 2, 1 pair of compounds was presented in a forward order (i.e., AX [right arrow] BX), whereas the 2nd pair of compounds was presented in a backward order (i.e., DY [right arrow] CY). Aversions established to AX and CY generalized less to BX than to DY. These results indicate that inhibitory associations contribute to perceptual learning in humans and thereby establish a fundamental similarity between the mechanisms that underlie perceptual learning in humans and rats. Keywords: perceptual learning, association, inhibition, flavor aversion, generalization

In 3 experiments, rats received preexposure to presentations of a compound flavor BX. The effective salience of B was then tested by assessing its ability to interfere with the aversion controlled by another flavor or the tendency to drink a saline solution after the induction of a salt need. It was found that the effective salience of B was maintained when during preexposure, presentations of BX alternated with presentations of X alone. This was true both when BX was presented as a simultaneous compound (Experiment 1) and as a serial compound (X [right arrow] B; Experiments 2 and 3); salience was not maintained when the serial compound took the form B [right arrow] X (Experiments 2 and 3a). It was argued that the salience of B declines during preexposure but is restored when presentations of X are able to activate the representation of B by way of the associative X-B link. Keywords: rat, conditioning, perceptual learning, stimulus salience

The authors studied the role of attention as a selection mechanism in implicit learning by examining the effect on primary sequence learning of performing a demanding target-selection task. Participants were trained on probabilistic sequences in a novel version of the serial reaction time (SRT) task, with dual- and triple-stimulus participants having to ignore irrelevant items in the SRT display. Despite large performance decrements under dual- and triple-stimulus configurations, testing under single-stimulus conditions revealed no impairment to sequence learning. These findings suggest that implicit sequence learning is resistant to disruption of the selection process. Results are discussed in terms of a componential model of attention and in relation to the implicit--explicit distinction. Keywords: selective attention, filtering cost, implicit--explicit distinction, automatic processing, perceptual load