Multiple regression analyses in artificial-grammar learning: The importance of control groups

In artificial-grammar learning, it is crucial to ensure that above-chance performance in the test stage is due to learning in the training stage but not due to judgemental biases. Here we argue that multiple regression analysis can be successfully combined with the use of control groups to assess whether participants were able to transfer knowledge acquired during training when making judgements about test stimuli. We compared the regression weights of judgements in a transfer condition (training and test strings were constructed by the same grammar but with different letters) with those in a control condition. Predictors were identical in both conditions—judgements of control participants were treated as if they were based on knowledge gained in a standard training stage. The results of this experiment as well as reanalyses of a former study support the usefulness of our approach.     

Second-order conditioning in human predictive judgements when there is little time to think

Associative accounts uniquely predict that second-order conditioning might be observed in human predictive judgements. Such an effect was found for cue X in two experiments in which participants were required to predict the outcomes of a series of training trials that included P + and PX-, but only when training was paced by requiring participants to make a prediction within 3 s on each trial. In Experiment 1 training on P + ended before training was given on PX - . In Experiment 2 trials with P+, PX-, T + and other cues were intermixed. In the unpaced group inhibitory learning was revealed by a summation test, TX versus TM, where M was a control stimulus. These results suggest either that pacing interferes with learning successive associations more than with learning simultaneous associations or that lack of time to think interferes with inferential processes required for this type of inhibitory learning.     

How does prior knowledge affect implicit and explicit concept learning?

Two experiments investigated the effect of prior knowledge on implicit and explicit learning. Implicit as opposed to explicit learning is sometimes characterized as unselective or purely statistical. During training, one group of participants was presented with category exemplars whose features could be tied together by integrative knowledge, whereas another group saw category exemplars with unrelated feature combinations. Half of the participants in each group learned these categories under a secondary-task condition (meant to discourage explicit learning), and the remaining half performed the categorization task under a single-task condition (meant to favour explicit learning). In a test phase, participants classified only the individual features of the training exemplars. Secondary- as opposed to single-task conditions impaired explicit but not implicit knowledge (as determined by subjective measures). Importantly, prior knowledge resulted in increased amounts of both implicit and explicit knowledge.     

Exploring specificity of speeded aiming movements: Examining different measures of transfer

Participants were trained and tested to move a mouse cursor from a start position to targets on a circular display in a perceptual-motor reversal condition, with horizontal, but not vertical, reversals. During training, some participants (experimental) moved to two targets either along a single diagonal axis (D1) or along both axes (D2). For D2, return movements from the targets were in the same direction as instructed movements to unpracticed targets. Others (control) trained on all targets. Testing always involved all targets. At test, movement times (to reach the target after leaving the start position) were shorter on trained than on untrained targets, especially for the D1 condition, documenting training specificity. However, movement times in the experimental conditions to new targets during testing were shorter than those in the control condition during training, documenting transfer of learning, with more transfer for D2 than for D1. Initiation times (to leave the start position after target onset) showed no transfer. The results provide evidence that specificity and transfer are not mutually exclusive and depend on the measure used to assess performance.     

Implicit sequence learning in a continuous pursuit-tracking task

Assessing implicit learning in the continuous pursuit-tracking task usually concerns a repeated segment of target displacements masked by two random segments, as referred to as Pew’s paradigm. Evidence for segment learning in this paradigm is scanty and contrasts with robust sequence learning in discrete tracking tasks. The present study investigates this issue with two experiments in which participants (N = 56) performed a continuous tracking task. Contrary to Pew’s paradigm, participants were presented with a training sequence that was continuously cycled during 14 blocks of practice, but Block 12 in which a transfer sequence was introduced. Results demonstrate sequence learning in several conditions except in the condition that was obviously the most similar to previous studies failing to induce segment learning. Specifically, it is shown here that a target moving too slowly combined with variable time at which target reversal occurs prevents sequence learning. In addition, data from a post-experimental recognition test indicate that sequence learning was associated with explicit perceptual knowledge about the repetitive structure. We propose that learning repetition in a continuous tracking task is conditional on its capacity to (1) allow participants to detect the repeated regularities and (2) restrict feedback-based tracking strategies.     

Information theory and artificial grammar learning: inferring grammaticality from redundancy

In artificial grammar learning experiments, participants study strings of letters constructed using a grammar and then sort novel grammatical test exemplars from novel ungrammatical ones. The ability to distinguish grammatical from ungrammatical strings is often taken as evidence that the participants have induced the rules of the grammar. We show that judgements of grammaticality are predicted by the local redundancy of the test strings, not by grammaticality itself. The prediction holds in a transfer test in which test strings involve different letters than the training strings. Local redundancy is usually confounded with grammaticality in stimuli widely used in the literature. The confounding explains why the ability to distinguish grammatical from ungrammatical strings has popularized the idea that participants have induced the rules of the grammar, when they have not. We discuss the judgement of grammaticality task in terms of attribute substitution and pattern goodness. When asked to judge grammaticality (an inaccessible attribute), participants answer an easier question about pattern goodness (an accessible attribute).     

Realism in confidence judgements of performance based on implicit learning

In two experiments we employed calibration methods to investigate the realism of participants' confidence ratings of their own classification performance based on knowledge acquired after training on an artificial grammar. In Experiment 1 participants showed good realism (but overconfidence) for grammatical strings but very poor realism for non-grammatical strings. Method of training (string repetition in writing or mere exposure) did not affect the realism. Furthermore, the participants underestimated their overall performance. In Experiment 2, using a more complex grammar and controlling for two types of associative chunk-strength, participants showed good realism (but still overconfidence) for both letter and symbol strings, irrespective of grammaticality. Together, these experiments show that implicit learning can give rise to knowledge products that are associated with fairly realistic meta-knowledge. It is argued that both the zero-correlation criterion and the guessing criterion are misplaced when used to define implicit knowledge; two reasons being that confidence judgements may be affected both by implicit knowledge and by inferences.     

The Relation Between Implicit and Explicit Learning: Evidence for Parallel Development

Much research has focused on the separability of implicit and explicit learning, but less has focused on how they might interact. A recent model suggests that in the motor-skill domain, explicit knowledge can guide movement, and the implicit system learns in parallel, based on these movements. Functional imaging studies do not support that contention, however; they indicate that learning is exclusively implicit or explicit. In the experiment reported here, participants learned a motor sequencing task either implicitly or explicitly. At transfer, most of the stimuli were random, but the sequence occasionally appeared; thus, it was not obvious that explicit knowledge could be applied to the task. Nevertheless, participants with explicit training showed sequence knowledge equivalent to those with implicit training, implying that implicit knowledge had been acquired in parallel with explicit knowledge. This result has implications for the development of automaticity and of motor-skill learning.     

Dual learning processes in interactive skill acquisition

Acquisition of interactive skills involves the use of internal and external cues. Experiment 1 showed that when actions were interdependent, learning was effective with and without external cues in the single-task condition but was effective only with the presence of external cues in the dual-task condition. In the dual-task condition, actions closer to the feedback were learned faster than actions farther away but this difference was reversed in the single-task condition. Experiment 2 tested how knowledge acquired in single and dual-task conditions would transfer to a new reward structure. Results confirmed the two forms of learning mediated by the secondary task: A declarative memory encoding process that simultaneously assigned credits to actions and a reinforcement-learning process that slowly propagated credits backward from the feedback. The results showed that both forms of learning were engaged during training, but only at the response selection stage, one form of knowledge may dominate over the other depending on the availability of attentional resources.     

学习条件和样例相似性对类别学习元认知监控的影响

采用“学习-迁移”范式 ,探讨了学习条件和样例相似性对类别学习元认知监控的影响。实验选取虚构动物材料,采用2（学习条件：规则、无规则）×3（样例相似性：低、中、高）×2（匹配类型：正向匹配、反向匹配）混合实验设计,结果显示,在规则条件下,高样例相似性组正向匹配新项目的分类正确率显著高于反向匹配新项目的分类正确率;在无规则条件下,样例相似性越高,正向匹配新项目的分类准确率越高,所有项目的信心值也越高。这表明,规则和样例相似性是类别学习元认知判断的线索;在同一任务中,分类会涉及基于规则和基于相似性两个过程。     

Auditory expectations for newly acquired structures

Our study investigated whether newly acquired auditory structure knowledge allows listeners to develop perceptual expectations for future events. For that aim, we introduced a new experimental approach that combines implicit learning and priming paradigms. Participants were first exposed to structured tone sequences without being told about the underlying artificial grammar. They then made speeded judgements on a perceptual feature of target tones in new sequences (i.e., in-tune/out-of-tune judgements). The target tones respected or violated the structure of the artificial grammar and were thus supposed to be expected or unexpected. In this priming task, grammatical tones were processed faster and more accurately than ungrammatical ones. This processing advantage was observed for an experimental group performing a memory task during the exposure phase, but was not observed for a control group, which was lacking the exposure phase (Experiment 1). It persisted when participants realized an in-tune/out-of-tune detection task during exposure (Experiment 2). This finding suggests that the acquisition of new structure knowledge not only influences grammaticality judgements on entire sequences (as previously shown in implicit learning research), but allows developing perceptual expectations that influence single event processing. It further promotes the priming paradigm as an implicit access to acquired artificial structure knowledge.     

The acquisition of morphological knowledge investigated through artificial language learning

Affix knowledge plays an important role in visual word recognition, but little is known about how it is acquired. The authors present a new method of investigating the acquisition of affixes in which participants are trained on novel affixes presented in novel word contexts (e.g., sleepnept). Experiment 1 investigated the role of semantic information on affix acquisition by comparing a form-learning condition with a condition in which participants also received definitions for each novel word. Experiment 2 investigated the role of long-term consolidation on affix acquisition by comparing knowledge of learned affixes two days and nearly two months after training. Results demonstrated that episodic knowledge of affixes can be acquired shortly after a single training session using either form or semantic learning, but suggested that the development of lexicalized representations of affixes requires the provision of semantic information during learning as well as a substantial period of offline consolidation.     

Training conditional and cumulative risk judgements: the role of frequencies,problem‐structure and einstellung

Two experiments implement and evaluate a training scheme for learning to apply frequency formats to probability judgements couched in terms of percentages. Results indicate that both conditional and cumulative probability judgements can be improved in this manner, however the scheme is insufficient to promote any deeper understanding of the problem structure. In both experiments, training on one problem type only (either conditional or cumulative risk judgements) resulted in an inappropriate transfer of a learned method at test. The obstacles facing a frequency‐based training programme for teaching appropriate use of probability data are discussed. Copyright © 2006 John Wiley & Sons, Ltd.     

The acquisition of morphological knowledge investigated through artificial language learning

Affix knowledge plays an important role in visual word recognition, but little is known about how it is acquired. The authors present a new method of investigating the acquisition of affixes in which participants are trained on novel affixes presented in novel word contexts (e.g., sleepnept). Experiment 1 investigated the role of semantic information on affix acquisition by comparing a form-learning condition with a condition in which participants also received definitions for each novel word. Experiment 2 investigated the role of long-term consolidation on affix acquisition by comparing knowledge of learned affixes two days and nearly two months after training. Results demonstrated that episodic knowledge of affixes can be acquired shortly after a single training session using either form or semantic learning, but suggested that the development of lexicalized representations of affixes requires the provision of semantic information during learning as well as a substantial period of offline consolidation.     

Caffeine cravings impair memory and metacognition

Cravings for food and other substances can impair cognition. We extended previous research by testing the effects of caffeine cravings on cued-recall and recognition memory tasks, and on the accuracy of judgements of learning (JOLs; predicted future recall) and feeling-of-knowing (FOK; predicted future recognition for items that cannot be recalled). Participants (N?=?55) studied word pairs (POND-BOOK) and completed a cued-recall test and a recognition test. Participants made JOLs prior to the cued-recall test and FOK judgements prior to the recognition test. Participants were randomly allocated to a craving or control condition; we manipulated caffeine cravings via a combination of abstinence, cue exposure, and imagery. Cravings impaired memory performance on the cued-recall and recognition tasks. Cravings also impaired resolution (the ability to distinguish items that would be remembered from those that would not) for FOK judgements but not JOLs, and reduced calibration (correspondence between predicted and actual accuracy) for JOLs but not FOK judgements. Additional analysis of the cued-recall data suggested that cravings also reduced participants’ ability to monitor the likely accuracy of answers during the cued-recall test. These findings add to prior research demonstrating that memory strength manipulations have systematically different effects on different types of metacognitive judgements.     

Evidence of blocking with geometric cues in a virtual watermaze

Three computer based experiments, testing human participants in a non-immersive virtual watermaze task, used a blocking design to assess whether two sets of geometric cues would compete in a manner described by associative models of learning. In stage 1, participants were required to discriminate between visually distinct platforms. In stage 2, additional spatial information was provided by the shape or the color of the walls of the pool. In a test trial, the platforms were removed and the spatial knowledge acquired regarding the position of the platform was assessed. Experimental groups were compared against control groups which did not receive stage 1 training. The unique color of the correct platform, in Experiments 1 and 3, disrupted learning about the colored walls but not the geometry of the pool. In Experiment 2, the correct platform was identifiable from its position within the three platform array. Learning the relative position of the correct platform within the array disrupted learning about its position relative to the geometry of the pool, but not to the colored walls. The results suggest that learning the position of a goal in relation to the geometry of the environment can be blocked but only by an alternative geometric cue.     

Prior knowledge and subtyping effects in children's category learning

Two experiments examined how 5- and 10-year-old children revise their category representations when exposed to exemplars that are congruent or incongruent with existing knowledge. During training children were presented with exemplars containing features that were congruent or incongruent with children's social stereotypes together with a stereotype-neutral feature. In the knowledge-subtyping condition this neutral feature predicted the stereotype-congruence of the other features. In the knowledge-standard condition the neutral feature was uncorrelated with stereotype-congruence. At test children made judgements about feature co-occurrence within the learned category. In each experiment these judgements were influenced by both stereotypical beliefs and exemplar observation. Stereotypical beliefs, however, had a greater influence on co-occurrence judgements in the knowledge-subtyping than in the standard conditions. In Experiment 2 these effects were shown to generalize to judgements about features that were not presented during training. These results challenge current models of knowledge-based categorization by showing that exemplar structure determines whether novel exemplar features are incorporated into category representations.     

个体差异对工作记忆训练迁移效果的调节

本研究考察了流体智力基线水平对工作记忆训练迁移效果的影响。采用前后测设计,以视觉和听觉双任务n-back作为工作记忆训练任务,对训练组进行为期一个月的训练;积极对照组采用阅读任务进行训练。结果发现积极控制组的流体智力水平在基线与后测之间无显著变化;而训练组流体智力水平在后测时与基线相比有显著提高,且工作记忆训练提升量越大的个体其流体智力改善越大。说明认知训练有效迁移到了流体智力水平的改善上。我们还发现流体智力基线水平调节了工作记忆训练对流体智力水平的迁移,即工作记忆训练提升量越大,流体智力改善值越大,对于那些流体智力基线水平较高的人来说,工作记忆训练对流体智力改善的效果更大。流体智力基线水平、工作记忆训练提升量及两者的乘积共同影响了流体智力改善值。这一结果表明个体差异如流体智力基线水平可以调节工作记忆训练对流体智力水平的迁移。     

Completely ruled out? Using response time data to investigate biconditional artificial grammar learning

Two experiments are reported on incidental learning using a biconditional artificial grammar (based on Johnstone & Shanks, 2001). Phonological repetition of rule-related letters was encouraged by requiring participants to write down and rehearse each training exemplar aloud for several seconds (Experiment 1). A cover story was introduced emphasising the relatedness of the two halves of each exemplar but without mentioning the rules (Experiment 2). Participants had no explicit knowledge of the rules and grammaticality classification was mostly at chance. Confidence judgements (Experiment 2) did not distinguish between numbers of correct and incorrect responses. The important finding was that response times were faster for grammatical than ungrammatical test exemplars. Results are discussed with reference to phonological phrasing, fluency, and competition between controlled and automatic processes.     

Orientation in trapezoid-shaped enclosures: implications for theoretical accounts of geometry learning

Human participants learned to select 1 of 4 distinctively marked corners in a rectangular virtual enclosure. After training, control and test trials were interspersed with training trials. On control and test trials, all markers were equivalent in color, but only during test trials was the shape of the enclosure manipulated. Specifically, for each test trial, a single long wall or short wall of the enclosure increased twice as long as or decreased half as long as that present in the training enclosure. These manipulations produced 8 unique trapezoid-shaped enclosures. Participants were allowed to select 1 corner during control and test trials. Performance during control trials revealed that participants selected the correct and rotationally equivalent locations. Performance during test trials revealed that participants selected locations in trapezoid-shaped enclosures that were consistent with those predicted by global geometry (i.e., principal axis of space) but were inconsistent with those predicted by local geometry (i.e., proportion of rewarded training features present at a location). Results have implications for theoretical accounts of geometry learning.