Detailed behavioral analysis as a window into cross-situational word learning

Recent research has demonstrated that word learners can determine word-referent mappings by tracking co-occurrences across multiple ambiguous naming events. The current study addresses the mechanisms underlying this capacity to learn words cross-situationally. This replication and extension of Yu and Smith (2007) investigates the factors influencing both successful cross-situational word learning and mis-mappings. Item analysis and error patterns revealed that the co-occurrence structure of the learning environment as well as the context of the testing environment jointly affected learning across observations. Learners also adopted an exclusion strategy, which contributed conjointly with statistical tracking to performance. Implications for our understanding of the processes underlying cross-situational word learning are discussed.     

Antipsychotic dose modulates behavioral and neural responses to feedback during reinforcement learning in schizophrenia

Schizophrenia is characterized by an abnormal dopamine system, and dopamine blockade is the primary mechanism of antipsychotic treatment. Consistent with the known role of dopamine in reward processing, prior research has demonstrated that patients with schizophrenia exhibit impairments in reward-based learning. However, it remains unknown how treatment with antipsychotic medication impacts the behavioral and neural signatures of reinforcement learning in schizophrenia. The goal of this study was to examine whether antipsychotic medication modulates behavioral and neural responses to prediction error coding during reinforcement learning. Patients with schizophrenia completed a reinforcement learning task while undergoing functional magnetic resonance imaging. The task consisted of two separate conditions in which participants accumulated monetary gain or avoided monetary loss. Behavioral results indicated that antipsychotic medication dose was associated with altered behavioral approaches to learning, such that patients taking higher doses of medication showed increased sensitivity to negative reinforcement. Higher doses of antipsychotic medication were also associated with higher learning rates (LRs), suggesting that medication enhanced sensitivity to trial-by-trial feedback. Neuroimaging data demonstrated that antipsychotic dose was related to differences in neural signatures of feedback prediction error during the loss condition. Specifically, patients taking higher doses of medication showed attenuated prediction error responses in the striatum and the medial prefrontal cortex. These findings indicate that antipsychotic medication treatment may influence motivational processes in patients with schizophrenia.     

Testing the limits of long-distance learning: learning beyond a three-segment window

Traditional flat-structured bigram and trigram models of phonotactics are useful because they capture a large number of facts about phonological processes. Additionally, these models predict that local interactions should be easier to learn than long-distance ones because long-distance dependencies are difficult to capture with these models. Long-distance phonotactic patterns have been observed by linguists in many languages, who have proposed different kinds of models, including feature-based bigram and trigram models, as well as precedence models. Contrary to flat-structured bigram and trigram models, these alternatives capture unbounded dependencies because at an abstract level of representation, the relevant elements are locally dependent, even if they are not adjacent at the observable level. Using an artificial grammar learning paradigm, we provide additional support for these alternative models of phonotactics. Participants in two experiments were exposed to a long-distance consonant-harmony pattern in which the first consonant of a five-syllable word was [s] or [∫] ("sh") and triggered a suffix that was either [-su] or [-∫u] depending on the sibilant quality of this first consonant. Participants learned this pattern, despite the large distance between the trigger and the target, suggesting that when participants learn long-distance phonological patterns, that pattern is learned without specific reference to distance.     

Generalization and similarity in exemplar models of categorization: Insights from machine learning

Exemplar theories of categorization depend on similarity for explaining subjects’ ability to generalize to new stimuli. A major criticism of exemplar theories concerns their lack of abstraction mechanisms and thus, seemingly, of generalization ability. Here, we use insights from machine learning to demonstrate that exemplar models can actually generalize very well. Kernel methods in machine learning are akin to exemplar models and are very successful in real-world applications. Their generalization performance depends crucially on the chosen similarity measure. Although similarity plays an important role in describing generalization behavior, it is not the only factor that controls generalization performance. In machine learning, kernel methods are often combined with regularization techniques in order to ensure good generalization. These same techniques are easily incorporated in exemplar models. We show that the generalized context model (Nosofsky, 1986) and ALCOVE (Kruschke, 1992) are closely related to a statistical model called kernel logistic regression. We argue that generalization is central to the enterprise of understanding categorization behavior, and we suggest some ways in which insights from machine learning can offer guidance.     

Social learning theory and cognitive behavioral models of body dysmorphic disorder

Contemporary cognitive behavioral models of body dysmorphic disorder are reviewed, whereby the first by Neziroglu and colleagues emphasizes conditioning processes and relational frame theory and the latter by Veale emphasizes information processing. A brief review of the existing cognitive behavioral therapy research follows the presentation of the models. The majority of publications on BDD continue to deal with phenomenology and epidemiology, and much more research on cognitive behavioral treatment is needed. Treatment research should be geared towards testing elements of the models explicated in this article, and randomized controlled trials are greatly needed.     

Generalization to unfamiliar talkers in artificial language learning

While there is evidence that talker-specific details are encoded in the phonetics of the lexicon (Kraljic, Samuel, & Brennan, Psychological Science 19(4):332–228, 2008; Logan, Lively, & Pisoni, Journal of the Acoustical Society of America, 89(2):874-886, 1991) and in sentence processing (Nygaard & Pisoni, Perception & Psychophysics, 60(3):355–376, 1998), it is unclear whether categorical linguistic patterns are also represented in terms of talker-specific details. The present study provides evidence that adult learners form talker-independent representations for productive linguistic patterns. Participants were able to generalize a novel linguistic pattern to unfamiliar talkers. Learners were exposed to spoken words that conformed to a pattern in which vowels of a word agreed in place of articulation, referred to as vowel harmony. All items were presented in the voice of one single talker. Participants were tested on items that included both the familiar talker and an unfamiliar talker. Participants generalized the pattern to novel talkers when the talkers spoke with a familiar accent (Experiment 1), as well as with an unfamiliar accent (Experiment 2). Learners showed a small advantage for talker familiarity when the words were familiar, but not when the words were novel. These results are consistent with a theory of language processing in which the lexicon stores fine-grained, talker-specific phonetic details, but productive linguistic processes are subject to abstract, talker-independent representations.     

Recency effects as a window to generalization: separating decisional and perceptual sequential effects in category learning

Accounts of learning and generalization typically focus on factors related to lasting changes in representation (i.e., long-term memory). The authors present evidence that shorter term effects also play a critical role in determining performance and that these recency effects can be subdivided into perceptual and decisional components. Experimental results based on a probabilistic category structure show that the previous stimulus exerts a contrastive effect on the current percept (perceptual recency) and that responses are biased toward or away from the previous feedback, depending on the similarity between successive stimuli (decisional recency). A method for assessing these recency effects is presented that clarifies open questions regarding stimulus generalization and perceptual contrast effects in categorization and in other domains.     

Opposition logic and neural network models in artificial grammar learning

Following neural network simulations of the two experiments of, argued that the opposition logic advocated by was incapable of distinguishing between single and multiple influences on performance of artificial grammar learning and more generally. We show that their simulations do not support their conclusions. We also provide different neural network simulations that do simulate the essential results of Higham et al. (2000).     

Memoirs of a locust: Density-dependent behavioral change as a model for learning and memory

A locust outbreak is a stupendous natural phenomenon that remains in the memory of whoever has been lucky (or unlucky) enough to witness it. Recent years have provided novel and important insights into the neurobiology of locust swarming. However, the central nervous system processes that accompany and perhaps even lie at the basis of locust phase transformation are still far from being fully understood. Our current work deals with the memory of a locust outbreak from a new perspective: that of the individual locust. We take locust density-dependent phase transformation – a unique example of extreme behavioral plasticity, and place it within the context of the accepted scheme of learning and memory. We confirm that a short time period of exposure to a small crowd of locusts is sufficient to induce a significant behavioral change in a previously solitary locust. Our results suggest that part of the behavioral change is due to long-term habituation of evasive and escape responses. We further demonstrate that the memory of a crowding event lasts for at least 24 h, and that this memory is sensitive to a protein synthesis blocker. These findings add much to our understanding of locust density-dependent phase polyphenism. Furthermore, they offer a novel and tractable model for the study of learning and memory-related processes in a very distinctive behavioral context.     

睡眠对恐惧学习的影响及其认知神经机制

睡眠问题可能会诱发恐惧相关情绪障碍(焦虑、创伤性应激障碍、恐怖症等),研究睡眠影响恐惧学习的认知神经机制,有助于增强对恐惧相关情绪障碍的预测、诊断和治疗。以往研究表明睡眠剥夺影响恐惧习得和消退主要是通过抑制vmPFC活动,阻碍其与杏仁核的功能连接,从而导致恐惧习得增强或是消退学习受损。进一步研究发现睡眠不同阶段对恐惧学习相关脑区有独特的影响:剥夺(缺乏)快速眼动睡眠会抑制vmPFC活动、增强杏仁核、海马激活,导致恐惧习得增强,消退学习受损,此外边缘皮层的功能连接减少破坏了记忆巩固(恐惧记忆和消退记忆);而慢波睡眠主要与海马变化有关,慢波睡眠期间进行目标记忆重激活可促进恐惧消退学习。未来研究需要增加睡眠影响恐惧泛化的神经机制研究、及昼夜节律中断对恐惧消退的影响,以及关注动物睡眠研究向人类睡眠研究转化中存在的问题。     

Increased responding to female stimuli as a result of sexual experience: Tests of mechanisms of learning

Sexual experience increases the response of males to stimuli provided by female conspecifics in a variety of species. The mechanisms of learning involved in this type of phenomenon were explored in two experiments with Japanese quail. The results indicated that instrumental conditioning with copulatory opportunity is not necessary for the acquisition of responding to female cues, and responding is not facilitated by learning about the location of the female. However, the response of males to female stimuli (as well as to arbitrary stimuli associated with access to a female) was enhanced by the presence of sexually conditioned contextual cues. Substantial levels of responding also occurred to female stimuli in a context where the subjects never encountered a female quail before. This latter outcome is consistent with the possibility that stimuli from a female become directly associated with sexual reinforcement during the course of sexual experience. Similar forms of learning may be involved in the effects of sexual experience on the response of mammalian species to female odours.     

Action mechanisms for social cognition: behavioral and neural correlates of developing Theory of Mind

Many psychological theories posit foundational links between two fundamental constructs: (1) our ability to produce, perceive, and represent action; and (2) our ability to understand the meaning and motivation behind the action (i.e. Theory of Mind; ToM). This position is contentious, however, and long‐standing competing theories of social‐cognitive development debate roles for basic action‐processing in ToM. Developmental research is key to investigating these hypotheses, but whether individual differences in neural and behavioral measures of motor action relate to social‐cognitive development is unknown. We examined 3‐ to 5‐year‐old children's (N = 26) EEG mu‐desynchronization during production of object‐directed action, and explored associations between mu‐desynchronization and children's behavioral motor skills, behavioral action‐representation abilities, and behavioral ToM. For children with high (but not low) mu‐desynchronization, motor skill related to action‐representation abilities, and action‐representation mediated relations between motor skill and ToM. Results demonstrate novel foundational links between action‐processing and ToM, suggesting that basic motor action may be a key mechanism for social‐cognitive development, thus shedding light on the origins and emergence of higher social cognition.     

Set recognition as a window to perceptual and cognitive processes

The Set visual perception game is a fertile research platform that allows investigation of perception, with gradual processing culminating in a momentary recognition stage, in a context that can be endlessly repeated with novel displays. Performance of the Set game task is a play-off between perceptual and conceptual processes. The task is to detect (among the 12 displayed cards) a 3-card set, defined as containing cards that are either all similar or all different along each of four dimensions with three possible values. We found preference and reduced response times (RTs) for perceiving set similarity (rather than span) and for including cards sharing the most abundant value in the display, suggesting that these are searched preferentially (perhaps by mutual enhancement). RT decreases with number of sets in the display according to a horse race model, implying independence of simultaneous searches. Central cards are included slightly more often, but set card proximity seems irrelevant. A supplementary experiment determining dimensional salience showed consistent but individual preferences, yet these seemed not to affect set identification. Training induced gradual improvement, which generalized to a new version of the game, suggesting high-level learning. We conclude that elements of perception such as similarity detection are basic for finding sets in this task, as in other real-world perceptual and cognitive tasks, suggesting the presence of basic similarity-perceiving mechanisms. The findings confirm the conclusion that conceptual processes are affected by perception.     

Predicting danger: the nature, consequences, and neural mechanisms of predictive fear learning

The ability to detect and learn about the predictive relations existing between events in the world is essential for adaptive behavior. It allows us to use past events to predict the future and to adjust our behavior accordingly. Pavlovian fear conditioning allows anticipation of sources of danger in the environment. It guides attention away from poorer predictors toward better predictors of danger and elicits defensive behavior appropriate to these threats. This article reviews the differences between learning about predictive relations and learning about contiguous relations in Pavlovian fear conditioning. It then describes behavioral approaches to the study of these differences and to the examination of subtle variations in the nature and consequences of predictive learning. Finally, it reviews recent data from rodent and human studies that have begun to identify the neural mechanisms for direct and indirect predictive fear learning.     

统计学习的认知神经机制及其与语言的关系

统计学习是指个体在连续刺激流中发现转移概率等统计规律的过程, 在Saffran等(1996)的经典婴儿语音切分研究中首次被提出。大量研究证实了统计学习的普遍存在, 近期学界开始关注统计学习的特异性及其对认知的影响, 尤其是从学习过程及其特异性两个方面阐述统计学习的认知神经机制并揭示其和语言的交互作用。未来应从脑和行为的多模态数据视角, 丰富统计学习结果的行为和神经指标, 考察不同类型统计学习过程的动态神经活动模式, 建立统计学习行为和脑的关联, 深化对统计学习认知神经机制的认识, 在统计学习与语言交互作用的基础上, 从成人二语学习切入结合音乐统计学习训练探讨促进语言学习的统计学习干预手段。     

Generalization of action knowledge following observational learning

Both observational and physical practices support the acquisition of motor skill knowledge in the form of spatiotemporal coordination patterns. The current experiment examined the extent that observation and physical practice can support the transfer of spatiotemporal knowledge and amplitude knowledge associated with motor skills. Evidence from a multijoint limb task revealed that knowledge about spatiotemporal patterns (relative phase) acquired by observers and models can be generalized exceptionally well within the trained arm (right) and across to the untrained arm (left). Transfer of relative phase occurred even when untrained combinations of joint amplitudes were required. This indicates that observation and physical practice both lead to the development of an effector-independent representation of the spatiotemporal knowledge in this task. Both observers and models showed some transfer of the relative amplitude knowledge, with observers demonstrating superior transfer for both a trained and untrained-arm transfer test, while the models were limited to positive transfer on an untrained-arm transfer test. The representation of movement amplitude knowledge is effector-independent in this task, but the use of that knowledge is constrained by the specific practice context and the linkage between the elbow and wrist.