The impact of training sequence and between-category similarity on unsupervised induction

Studies of supervised categorization often show better learning when examples are presented in random alternation rather than massed by category, but such interleaving impairs learning in unsupervised tasks. The exemplar comparison hypothesis explains this result by assuming that people in unsupervised tasks discover generalizations about categories by comparing individual examples, and that interleaving increases the difficulty of such within-category comparisons. The category invention hypothesis explains the interleaving effect by assuming that people are more likely to merge or aggregate potentially separable categories when they are interleaved, and this initial failure to recognize separate categories then acts as an effective barrier to further learning. The present experiments show that the interleaving effect depends on the similarity or alignability of the presented categories. This result provides evidence in favour of the category invention hypothesis, which expects that highly dissimilar (nonalignable) categories will resist aggregation and hence will not be affected by interleaving. The nonmonotonic pattern of learning, and the interaction between sequence and similarity, observed in the alignable conditions of Experiment 3 were also consistent with category invention, but not with exemplar comparison. Implications are discussed for real-world learning, especially the relationship between exposure and learning and between supervised and unsupervised learning.     

Weighing the past and the future in decision making

Prior irreversible investments of money, time, or effort referred to as sunk costs frequently lead to decisions to continue a chosen course of action despite that this is irrational. With the aim of demonstrating that such escalation of commitment is a special case of a more general phenomenon, two experiments were carried out employing undergraduates as participants. Experiment 1 showed for fictitious personal and business investment scenarios that both prior losses and gains (sunk outcomes) affected choices to continue or discontinue the investment. In Experiment 2 the effect of sunk outcomes was reduced although not eliminated by a monetary bonus that in one condition depended on the future outcomes of the second gamble in two-stage gambles, in another condition on the future returns in personal investment scenarios. In support of a more inclusive theory subsuming escalation of commitment, the decisions were affected by both past and future outcomes and both gains and losses.     

The role of perceptual salience during the segmentation of connected speech

Statistical learning allows listeners to track transitional probabilities among syllable sequences and use these probabilities for subsequent speech segmentation. Recent studies have shown that other sources of information, such as rhythmic cues, can modulate the dependencies extracted via statistical computation. In this study, we explored how syllables made salient by a pitch rise affect the segmentation of trisyllabic words from an artificial speech stream by native speakers of three different languages (Spanish, English, and French). Results showed that, whereas performance of French participants did not significantly vary across stress positions (likely due to language-specific rhythmic characteristics), the segmentation performance of Spanish and English listeners was unaltered when syllables in word-initial and word-final positions were salient, but it dropped to chance level when salience was on the medial syllable. We argue that pitch rise in word-medial syllables draws attentional resources away from word boundaries, thus decreasing segmentation effectiveness.     

Spreading the words: A spacing effect in vocabulary learning

The spacing effect refers to the frequently observed finding that distributing learning across time leads to better retention than massing it into one single study session. In the present study, we examined whether the spacing effect generalises to primary school vocabulary learning. To this aim, children from Grade 3 were taught the meaning of 15 new words using a massed procedure and 15 other new words using a spaced procedure. The 15 words in the massed condition were divided into three sets of five words, and each set was taught three times in one of three learning sessions. In the spaced condition, learning was distributed across the three sessions: All 15 words were practised once in each of the three learning sessions. At the retention tests after 1 week and after 5 weeks we observed that the meaning of spaced words was remembered better than the meaning of massed words.     

Phases of procedural learning and memory: characterisation with perceptual-motor sequence tasks

ABSTRACT

Procedural learning and memory has been conceptualised as consisting of cognitive and autonomous phases. Although the Serial Reaction Time Task (SRTT) is a popular task used to study procedural memory (PM), it has not been used to explore the different phases of PM. The present study employed a modified SRTT and investigated whether it can distinguish phases of PM. Our results revealed that performance at the beginning of typing a repeating sequence was marked by a steep learning curve, followed by gradual improvements and ending in high performance levels without further improvement. Steep performance increases characterise the effortful learning of the cognitive phase, gradual increases at higher performances characterise emerging automatisation of the associative phase, and sustained highest performance characterises autonomous procedures when PM has formed. Our study presents an easy-to-use measure, capable of distinguishing phases of PM, and which can be useful to assess PM during brain development.     

An investigation of students' knowledge of the delayed judgements of learning effect

Judgements of learning (JOL) of paired associates can be made immediately after learning or after a delay, while viewing the first word (cue) only or both words (cue–target) in a pair. Delayed cue-only judgements are more related to subsequent memory performance than delayed cue–target, immediate cue-only, or immediate cue–target judgements. In two experiments we tested students' knowledge of this delayed JOL effect and whether their knowledge increases as a function of task experience (Experiment 2). The majority of the participants did not choose the more effective judgement strategy and they did not systematically alter their behaviour as a function of task experience. Instead, a subset of the participants selected judgement strategies on the basis of a learning goal, that is, a strategy that let them restudy both words in a pair. In sum, most students appear to be unaware of the powerful influence of delayed cue-only JOLs on monitoring accuracy.     

Using mnemonic images and explicit sound contrasting to help Japanese children learn English alphabet sounds

Although mnemonics have been shown to be effective in remembering letter-sound associations, the use of foreign words as cues for English phonemes had not been investigated. Learning phonemes in Japan is challenging because the Japanese language is based on a different sound unit called mora (mostly consonant-vowel combinations). This study investigated the effectiveness of using mnemonic images utilizing Japanese words as cues for the phonemes, and explicit sound contrasting of phonemic sounds with morae they could be confused with, in facilitating children's acquisition of knowledge about alphabet letter-sound correspondence. The participants were 140 6th-grade Japanese students who were taught phoneme-consonant correspondence, with or without the use of mnemonics or explicit sound contrasting. Analysis of the students’ pre- and post-instruction assessments revealed significant interaction effects between types of instruction provided and instruction phase, indicating better performance in letter-sound association as a consequence of the inclusion of both mnemonics and explicit sound contrasting.     

人工语法中的内隐学习实验研究

用Reber等人发明的人工语法和人工语法学习程序,研究在复杂规则学习中的内隐学习与外显学习过程.实验结果发现内隐学习中启动效应存在,内隐学习效应明显,支持Reber等人提出的内隐学习理论;对内隐记忆与外显记忆关系的研究,支持杨治良等(1998)提出的内隐和外显记忆的"钢筋水泥"结构性模型的假设.     

The relation of learning disabilities to the long-term outcomes of concussion

ObjectiveThis study sought to cross-sectionally evaluate the relation between learning disorders (LD) and long-term concussion outcomes.MethodSeventy-three asymptomatic male university athletes (23 history of concussion with LD; 24 history of concussion no LD; 26 controls) completed the Beck Depression Inventory-2 (BDI-II), the Profile of Mood States (POMS), the Cogstate battery, and an Oddball task during which event-related brain potentials were recorded.ResultsConcussed athletes with LD exhibited greater depressive symptoms (BDI-II), greater total mood disturbance (POMS), decreased accuracy on the One-Card Learning and the N-back task (Cogstate), decreased accuracy on the Oddball task, and reduced ERN amplitude relative to both the concussed athletes without a LD and controls. Concussed athletes with LD also exhibited prolonged P3 latency relative to controls. Irrespective of LD, concussed athletes exhibited increased anger-hostility and decreased Pe amplitudes relative to controls. No differences were observed in P3a amplitude or latency.ConclusionHaving LD may be a significant factor moderating the neurophysiological, cognitive and psycho-affective outcomes of concussion, and may explain a significant portion of the persistent deficits observed by researchers and clinicians.     

Prism adaptation in schizophrenia

The prism adaptation test examines procedural learning (PL) in which performance facilitation occurs with practice on tasks without the need for conscious awareness. Dynamic interactions between frontostriatal cortices, basal ganglia, and the cerebellum have been shown to play key roles in PL. Disruptions within these neural networks have also been implicated in schizophrenia, and such disruptions may manifest as impairment in prism adaptation test performance in schizophrenia patients. This study examined prism adaptation in a sample of patients diagnosed with schizophrenia (N=91) and healthy normal controls (N=58). Quantitative indices of performance during prism adaptation conditions with and without visual feedback were studied. Schizophrenia patients were significantly more impaired in adapting to prism distortion and demonstrated poorer quality of PL. Patients did not differ from healthy controls on aftereffects when the prisms were removed, but they had significantly greater difficulties in reorientation. Deficits in prism adaptation among schizophrenia patients may be due to abnormalities in motor programming arising from the disruptions within the neural networks that subserve PL.