The subliminal mere exposure effect does not generalize to structurally related stimuli.

R. F. Bornstein (1994) questioned whether subliminal mere exposure effects might generalize to structurally related stimuli, thereby providing evidence for the existence of implicit learning. Two experiments examined this claim using letter string stimuli constructed according to the rules of an artificial grammar. Experiment 1 demonstrated that brief, masked exposure to grammatical strings impaired recognition but failed to produce a mere exposure effect on novel structurally related strings seen at test. Experiment 2 replicated this result but also demonstrated that a reliable mere exposure effect could be obtained, provided the same grammatical strings were presented at test. The results suggest that the structural relationship between training and test items prevents the mere exposure effect when participants are unaware of the exposure status of stimuli, and therefore provide no evidence for the existence of implicit learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit Learning of Musical Timbre Sequences: Statistical Regularities Confronted With Acoustical (Dis)Similarities.

The present study investigated the influence of acoustical characteristics on the implicit learning of statistical regularities (transition probabilities) in sequences of musical timbres. The sequences were constructed in such a way that the acoustical dissimilarities between timbres potentially created segmentations that either supported (S1) or contradicted (S2) the statistical regularities or were neutral (S3). In the learning group, participants first listened to the continuous timbre sequence and then had to distinguish statistical units from new units. In comparison to a control group without the exposition phase, no interaction between sequence type and amount of learning was observed: Performance increased by the same amount for the three sequences. In addition, performance reflected an overall preference for acoustically similar timbre units. The present outcome extends previous data from the domain of implicit learning to complex nonverbal auditory material. It further suggests that listeners become sensitive to statistical regularities despite acoustical characteristics in the material that potentially affect grouping. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A case of syntactical learning and judgment: How conscious and how abstract?

Examined 2 possible bases for grammatical judgments following syntactical learning: unconscious representations of a formal grammar, as in A. S. Reber's (see record 1976-21811-001) hypothesis of implicit learning, and conscious rules within information grammars. 50 undergraduates inspected strings generated by a finite-state grammar, viewed either one at a time or all at a time, with implicit or explicit learning instructions. 15 undergraduates served as controls. In a transfer test, Ss and controls judged the grammaticality of grammatical and nongrammatical strings and reported the bases for their judgments. Concurrent with previous results, Ss correctly classified a significant number of novel strings, indicating the operation of grammatical abstraction. However, reported rules predicted those grammatical judgments without significant residual. Ss acquired correlated grammars—personal sets of conscious rules, each of limited scope and many of imperfect validity. The rules embodied abstractions, consciously represented novelty that could account for abstraction embodied in judgments. It is argued that a better explanation of these results credits grammatical judgments to conscious rules within informal grammars rather than to unconscious representations of a formal grammar. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Influence of Grammatical, Local, and Organizational Redundancy on Implicit Learning: An Analysis Using Information Theory.

People behave as if they know the structure of their environment. Because people rarely study that structure explicitly, several theorists have postulated an implicit learning system that abstracts that structure automatically. An alternative view is that people respond to local structure that derives from global structure. Measures are developed that quantify structure in a set of stimuli, in individual stimuli, and in encoded stimuli. The authors apply the measures to examine serial recall for sequences of colors generated using a stationary Markov grammar. They demonstrate that the 3 kinds of redundancy are confounded and show that the memorial advantage for grammatical stimuli reflects participants' use of local expressions of grammatical structure to aid learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit Spatial Contextual Learning in Healthy Aging.

Three experiments investigated the aging of implicit spatial and spatiotemporal context learning in 2 tasks. In contextual cuing, people learn to use repeated spatial configurations to facilitate search for a target, whereas in higher order serial learning, they learn to use subtle sequence regularities to respond more quickly and accurately to a series of events. Results reveal a dissociation; overall contextual cuing is spared in healthy aging, whereas higher order sequence learning is impaired in the same individuals. This finding suggests that these 2 forms of implicit learning rely on different neural substrates that age differently; the results are also consistent with recent evidence that fronto-striatal circuits are particularly susceptible to decline in health aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative chunk strength in artificial grammar learning.

In 4 experiments, adherence to grammatical rules and associative chunk strength (including different measures, each calculated on the basis of the frequency with which bigrams and trigrams present in the test strings appeared in the learning strings) were manipulated independently in the test phase of an artificial grammar learning task. When participants learned few items of the grammar (Experiments 1A and 2A), the associated items were more often classified as grammatical than the nonassociated ones. On the other hand, when the learning phase included most of the grammatical items (Experiments 1B and 2B), the only effect observed was an effect of grammaticality. These results suggest that, depending on the specific constraints of the tasks, knowledge based on bigrams and trigrams and knowledge based on the abstraction of the grammatical structure can be used for the classification task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychometric intelligence dissociates implicit and explicit learning.

The hypothesis that performance on implicit learning tasks is unrelated to psychometric intelligence was examined in a sample of 605 German pupils. Performance in artificial grammar learning, process control, and serial learning did not correlate with various measures of intelligence when participants were given standard implicit instructions. Under an explicit rule discovery instruction, however, a significant relationship between performance on the learning tasks and intelligence appeared. This finding provides support for Reber's hypothesis that implicit learning, in contrast to explicit learning, is independent of intelligence, and confirms thereby the distinction between the 2 modes of learning. However, because there were virtually no correlations among the 3 learning tasks, the assumption of a unitary ability of implicit learning was not supported. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The conscious, the unconscious, and familiarity.

This article examines the role of subjective familiarity in the implicit and explicit learning of artificial grammars. Experiment 1 found that objective measures of similarity (including fragment frequency and repetition structure) predicted ratings of familiarity, that familiarity ratings predicted grammaticality judgments, and that the extremity of familiarity ratings predicted confidence. Familiarity was further shown to predict judgments in the absence of confidence, hence contributing to above-chance guessing. Experiment 2 found that confidence developed as participants refined their knowledge of the distribution of familiarity and that differences in familiarity could be exploited prior to confidence developing. Experiment 3 found that familiarity was consciously exploited to make grammaticality judgments including those made without confidence and that familiarity could in some instances influence participants' grammaticality judgments apparently without their awareness. All 3 experiments found that knowledge distinct from familiarity was derived only under deliberate learning conditions. The results provide decisive evidence that familiarity is the essential source of knowledge in artificial grammar learning while also supporting a dual-process model of implicit and explicit learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual Feature Learning in Artificial Grammar Classification.

The Artificial Grammar Learning task has been used extensively to assess individuals' implicit learning capabilities. Previous work suggests that participants implicitly acquire rule-based knowledge as well as exemplar-specific knowledge in this task. This study investigated whether exemplar-specific knowledge acquired in this task is based on the visual features of the exemplars. When a change in the font and case occurred between study and test, there was no effect on sensitivity to grammatical rules in classification judgments. However, such a change did virtually eliminate sensitivity to training frequencies of letter bigrams and trigrams (chunk strength) in classification judgments. Performance of a secondary task during study eliminated this font sensitivity and generally reduced the contribution of chunk strength knowledge. The results are consistent with the idea that perceptual fluency makes a contribution to artificial grammar judgments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The transfer effect in artificial grammar learning: Reappraising the evidence on the transfer of sequential dependencies.

Exposure to sequences of elements generated by an artificial grammar enables observers to classify new sequences presented either with the same (within-domain) or different (across-domain) vocabulary elements as being well- or ill-formed according to that grammar (A. S. Reber, 1969). Experiment 1 replicated G. T. M. Altmann, Z. Dienes, and A. Goode's (1995) demonstration of this effect, but inspection of hits and correct rejections revealed that a single cue was used to reject a subset of the ungrammatical sequences. Experiment 2 removed this cue, and participants no longer discriminated between grammatical and ungrammatical sequences in the novel domain. The authors conclude that G. T. M. Altmann et al.'s demonstration of discrimination in the novel domain did not necessitate the application of knowledge pertaining to sequential dependencies. Implications of the data for other studies, showing abstraction of knowledge across test sequences, are also considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incidental and intentional sequence learning in youth-onset psychosis and attention-deficit/hyperactivity disorder (ADHD).

The goal was to compare incidental and intentional spatial sequence learning in youth-onset psychosis and ADHD. The authors tested 8- to 19-year-olds with psychosis or ADHD and healthy controls on a serial reaction time (RT) task and used manual and oculomotor measures to examine learning. Participants were also administered a block in which they were explicitly instructed to learn a sequence. As in our previous studies with healthy adults and children, oculomotor anticipations and RTs showed learning effects similar to those in the manual modality. Results showed intact sequence-specific learning but fewer oculomotor anticipations in both clinical groups during incidental learning. In intentional learning, only the psychosis group showed impairments compared to controls. There were no interactions between age and diagnosis. Thus, the psychosis group showed relatively preserved incidental learning despite impairments in intentional learning. Additionally, both clinical groups showed impairments in the ability to search for, extract, and anticipate regularities (whether the regularities were there or not), but not in the ability to respond to these regularities when they were there. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impaired implicit learning in schizophrenia.

Schizophrenia patients consistently show deficits on tasks of explicit learning and memory. In contrast, their performance on implicit processing tasks often appears to be relatively intact, although most studies have focused on implicit learning of motor skills. This study evaluated implicit learning in 59 medicated schizophrenia outpatients and 43 controls using 2 different cognitive skill tasks. Participants completed a probabilistic classification task to assess procedural habit learning and an artificial grammar task to assess incidental learning of complex rule-based knowledge, as well as an explicit verbal learning and memory task. In addition to performing worse than controls on the explicit learning task, patients showed worse overall performance on the probabilistic classification task, which involves gradual learning through trial-by-trial performance feedback. However, patients and controls showed similar levels of learning on the artificial grammar task, suggesting a preserved ability to acquire complex rule-based knowledge in the absence of performance feedback. Discussion focuses on possible explanations for schizophrenia patients' poor probabilistic classification task performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatial attention and implicit sequence learning: Evidence for independent learning of spatial and nonspatial sequences.

This research investigated whether regular spatial orienting sequences can be learned implicitly and independently of response requirements. In a new version of a serial response task introduced by M. J. Nissen and P. Bullemer (1987) participants had to discriminate between objects that could occur at different locations. Independent sequences determined the succession of locations and objects. Even participants who were not aware of any regularities exhibited evidence for learning of both sequences (Experiment 1). Experiment 2 showed that the joint learning of spatial and object sequences was as efficient as learning of single sequences and that it even occurred when learning required memory for past sequence elements and attention was blocked through a secondary tone-counting task. Results are consistent with the idea that independent systems may exist for the implicit acquisition of spatial and nonspatial regularities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Abstract Analogies and Positive Transfer in Artificial Grammar Learning.

Following Brooks and Vokey (1991), we show that positive transfer to new items generated from an artificial grammar in which the vocabulary has been changed from training to test can be based on "abstract analogy" to specific training items (specific similarity) rather than abstraction of a grammar and symbol remapping rules, even with remapping unique to each test item. The results confirm that transcendence over symbols provides no support for the implicit learning of abstract structure. Ironically, they also show that the effect of specific similarity does not depend on surface characteristics of the items, but the residual effect of grammaticality does. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Encoder: A Connectionist Model of How Learning to Visually Encode Fixated Text Images Improves Reading Fluency.

This article proposes that visual encoding learning improves reading fluency by widening the span over which letters are recognized from a fixated text image so that fewer fixations are needed to cover a text line. Encoder is a connectionist model that learns to convert images like the fixated text images human readers encode into the corresponding letter sequences. The computational theory of classification learning predicts that fixated text-image size makes this learning difficult but that reducing image variability and biasing learning should help. Encoder confirms these predictions. It fails to learn as image size increases but achieves humanlike visual encoding accuracy when image variability is reduced by regularities in fixation positions and letter sequences and when learning is biased to discover mapping functions based on the sequential, componential structure of text. After training, Encoder exhibits many humanlike text familiarity effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incidentally, things in general are particularly determined: An episodic-processing account of implicit learning.

People can become sensitive to the rules of a grammar without awareness. A. S. Reber (1989) and others have argued that this implicit learning results from automatic abstraction of general structure. Instead, it is argued that people perform only those operations required to satisfy known demands. In various tasks, Ss learned the structures of individual items, coded experiences of processing items in specific ways, or abstracted elements of the general structure: There was no evidence that Ss abstracted structure when it was not required to perform the immediate task. Each type of knowledge was acquired without awareness that the domain had a general structure, but each made Ss sensitive to certain aspects of that structure, enabling them to identify grammatical items in an unanticipated test. The conclusion is that implicit sensitivity to general structure is accidental, a by-product of coding whatever Ss experience in processing stimuli for another purpose. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Artificial grammar learning depends on implicit acquisition of both abstract and exemplar-specific information.

The contributions of exemplar-specific and abstract knowledge to artificial grammar learning were examined in amnesic patients and controls. In Experiment 1, grammatical rule adherence and chunk strength exerted separate effects on grammaticality judgments. Amnesic patients exhibited intact classification performance, demonstrating the same pattern of results as controls. In Experiment 2, amnesic patients exhibited impaired declarative memory for chunks. In Experiment 3, both amnesic patients and controls exhibited transfer when tested with a letter set different than the one used for training, although performance was better when the same letter sets were used at training and test. The results suggest that individuals learn both abstract information about training items and exemplar-specific information about chunk strength and that both types of learning occur independently of declarative memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic contextual cuing and visual attention.

Since M. M. Chun and Y. Jiang's (1998) original study, a large body of research based on the contextual cuing paradigm has shown that the visuocognitive system is capable of capturing certain regularities in the environment in an implicit way. The present study investigated whether regularities based on the semantic category membership of the context can be learned implicitly and whether that learning depends on attention. The contextual cuing paradigm was used with lexical displays in which the semantic category of the contextual words either did or did not predict the target location. Experiments 1 and 2 revealed that implicit contextual cuing effects can be extended to semantic category regularities. Experiments 3 and 4 indicated an implicit contextual cuing effect when the predictive context appeared in an attended color but not when the predictive context appeared in an ignored color. However, when the previously ignored context suddenly became attended, it immediately facilitated performance. In contrast, when the previously attended context suddenly became ignored, no benefit was observed. Results suggest that the expression of implicit semantic knowledge depends on attention but that latent learning can nevertheless take place outside the attentional field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theories of artificial grammar learning.

Artificial grammar learning (AGL) is one of the most commonly used paradigms for the study of implicit learning and the contrast between rules, similarity, and associative learning. Despite five decades of extensive research, however, a satisfactory theoretical consensus has not been forthcoming. Theoretical accounts of AGL are reviewed, together with relevant human experimental and neuroscience data. The author concludes that satisfactory understanding of AGL requires (a) an understanding of implicit knowledge as knowledge that is not consciously activated at the time of a cognitive operation; this could be because the corresponding representations are impoverished or they cannot be concurrently supported in working memory with other representations or operations, and (b) adopting a frequency-independent view of rule knowledge and contrasting rule knowledge with specific similarity and associative learning (co-occurrence) knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit learning of nonlocal musical rules: A comment on Kuhn and Dienes (2005).

In a recent study, G. Kuhn and Z. Dienes (2005) reported that participants previously exposed to a set of musical tunes generated by a biconditional grammar subsequently preferred new tunes that respected the grammar over new ungrammatical tunes. Because the study and test tunes did not share any chunks of adjacent intervals, this result may be construed as straightforward evidence for the implicit learning of a structure that was only governed by nonlocal dependency rules. It is shown here that the grammar modified the statistical distribution of perceptually salient musical events, such as the probability that tunes covered an entire octave. When the influence of these confounds was removed, the effect of grammaticality disappeared. (PsycINFO Database Record (c) 2010 APA, all rights reserved)