Capacities underlying word learning

Children are strikingly good at learning the meanings of words. Current controversy focuses on the relative importance of different capacities in this learning process including principles of association, low-level attentional mechanisms, special word learning constraints, syntactic cues and theory of mind. We argue that children succeed at word learning because they possess certain conceptual biases about the external world, the ability to infer the referential intentions of others and an appreciation of syntactic cues to word meaning. Support for this view comes from studies exploring the phenomena of fast mapping, the whole object bias, the acquisition of names for entities belonging to different ontological kinds and the effect of lexical contrast. Word learning is not the result of a general associative learning process, nor does it involve specialized constraints. The ability to learn the meanings of words depends on a number of capacities, some of which are specific to language and unique to humans, others of which are potentially shared with other species.     

Knowledge and success from ability

This paper argues that knowledge is an instance of a more general and familiar normative kind—that of success through ability (or success through excellence, or success through virtue). This thesis is developed in the context of three themes prominent in the recent literature: that knowledge attributions are somehow context sensitive; that knowledge is intimately related to practical reasoning; and that one purpose of the concept of knowledge is to flag good sources of information. Wedding these themes to the proposed account helps to explain a wide range of standard Gettier problems. It also helps to explain barn façade cases, which require a different kind of treatment.     

Cellular and molecular mechanisms underlying learning and memory impairments produced by cannabinoids

Why does smoking marijuana impair learning and memory? Behavioral studies suggest that a disruption of normal hippocampal function contributes to these deficits. In vitro experiments find that cannabinoid receptor activation reduces neurotransmitter release below the levels required to trigger long-term changes in synaptic strength in the hippocampus. Cannabinoids reduce glutamate release through a G-protein-mediated inhibition of the calcium channels responsible for neurotransmitter release from hippocampal neurons. These mechanisms likely play a role in the learning and memory impairments produced by cannabinoids and by endogenous cannabinoid receptor ligands.     

Mechanisms underlying an ability to behave ethically

Cognitive neuroscientists have anticipated the union of neural and behavioral science with ethics (Gazzaniga 2005). The identification of an ethical rule--the dictum that we should treat others in the manner in which we would like to be treated--apparently widespread among human societies suggests a dependence on fundamental human brain mechanisms. Now, studies of neural and molecular mechanisms that underlie the feeling of fear suggest how this form of ethical behavior is produced. Counterintuitively, a new theory presented here states that it is actually a loss of social information that leads to sharing others' fears with our own, thus allowing us to treat others as we would like to be treated. Adding to that hypothetical mechanism is the well-studied predilection toward affiliative behaviors. Thus, even as Chomsky hypothesizes that humans are predisposed to utter grammatical sentences, we propose that humans are 'wired for reciprocity'. However, these two neural forces supporting ethical behavior do not explain individual or collective violence. At any given moment, the ability to produce behavior that obeys this ethical rule is proposed to depend on a balance between mechanisms for prosocial and antisocial behaviors. That balance results not only from genetic influences on temperament but also from environmental effects particularly during critical neonatal and pubertal periods.     

Temporal and spectral dynamics underlying cognitive control modulated by task-irrelevant stimulus-response learning

Behavioral and recent neuroimaging findings have shown reversal of interference effects due to manipulating proportion congruency (PC), which suggests that task-irrelevant stimulus-response (S-R) associations are strengthened and applied to predict responses. However, it is unclear how the strengthened S-R associations are represented and applied in the brain. We investigated with a between-subjects PC paradigm of the Hedge and Marsh task using electroencephalography (EEG). The behavioral results showed the reversal of the conflict effects, suggesting that task-irrelevant S-R associations were strengthened and used to prepare responses. The EEG results revealed the PC-related reversal of the conflict effects in the frontocentral N2 and parietal P3b amplitudes. Time-frequency analyses showed more pronounced PC-related reversal of the conflict effects in theta band (4–8 Hz) activity in frontocentral sites. These results suggest that the strengthened S-R associations due to PC manipulation modulated cognitive control. Importantly, the amplitude of lateralized readiness potential was higher in the high-PC condition than in the low-PC condition, suggesting that the strengthened short-term-memory spatial S-R associations that modulated cognitive control were applied similarly to long-term-memory spatial S-R associations.     

人际互动中社会学习的计算神经机制

人类在社会互动中通过他人的行为对他人特质、意图及特定情境下的社会规范进行学习, 是优化决策、维护积极社会互动的重要条件。近年来, 越来越多的研究通过结合计算模型与神经影像技术对社会学习的认知计算机制及其神经基础进行了深入考察。已有研究发现, 人类的社会学习过程能够较好地被强化学习模型与贝叶斯模型刻画, 主要涉及的认知计算过程包括主观期望、预期误差和不确定性的表征以及信息整合的过程。大脑对这些计算过程的执行主要涉及奖惩加工相关脑区(如腹侧纹状体与腹内侧前额叶)、社会认知加工相关脑区(如背内侧前额叶和颞顶联合区)及认知控制相关脑区(如背外侧前额叶)。需要指出的是, 计算过程与大脑区域之间并不是一一映射的关系, 提示未来研究可借助多变量分析与脑网络分析等技术从系统神经科学的角度来考察大尺度脑网络如何执行不同计算过程。此外, 将来研究应注重生态效度, 利用超扫描技术考察真实互动下的社会学习过程, 并更多地关注内隐社会学习的计算与神经机制。     

Knowledge and the value of cognitive ability

We challenge a line of thinking at the fore of recent work on epistemic value: the line (suggested by Kvanvig in The value of knowledge and the pursuit of understanding, 2003 and others) that if the value of knowledge is “swamped” by the value of mere true belief, then we have good reason to doubt its theoretical importance in epistemology. We offer a value-driven argument for the theoretical importance of knowledge—one that stands even if the value of knowledge is “swamped” by the value of true belief. Specifically, we contend that even if knowledge itself has no special epistemic value, its relationship to other items of value—cognitive abilities—gives ample reason to locate the concept at the very core of epistemology.     

Implicit learning as an ability

The ability to automatically and implicitly detect complex and noisy regularities in the environment is a fundamental aspect of human cognition. Despite considerable interest in implicit processes, few researchers have conceptualized implicit learning as an ability with meaningful individual differences. Instead, various researchers (e.g., Reber, 1993; Stanovich, 2009) have suggested that individual differences in implicit learning are minimal relative to individual differences in explicit learning. In the current study of English 16–17 year old students, we investigated the association of individual differences in implicit learning with a variety of cognitive and personality variables. Consistent with prior research and theorizing, implicit learning, as measured by a probabilistic sequence learning task, was more weakly related to psychometric intelligence than was explicit associative learning, and was unrelated to working memory. Structural equation modeling revealed that implicit learning was independently related to two components of psychometric intelligence: verbal analogical reasoning and processing speed. Implicit learning was also independently related to academic performance on two foreign language exams (French, German). Further, implicit learning was significantly associated with aspects of self-reported personality, including intuition, Openness to Experience, and impulsivity. We discuss the implications of implicit learning as an ability for dual-process theories of cognition, intelligence, personality, skill learning, complex cognition, and language acquisition.     

Development switch in neural circuitry underlying odor-malaise learning

Fetal and infant rats can learn to avoid odors paired with illness before development of brain areas supporting this learning in adults, suggesting an alternate learning circuit. Here we begin to document the transition from the infant to adult neural circuit underlying odor-malaise avoidance learning using LiCl (0.3 M; 1% of body weight, ip) and a 30-min peppermint-odor exposure. Conditioning groups included: Paired odor-LiCl, Paired odor-LiCl-Nursing, LiCl, and odor-saline. Results showed that Paired LiCl-odor conditioning induced a learned odor aversion in postnatal day (PN) 7, 12, and 23 pups. Odor-LiCl Paired Nursing induced a learned odor preference in PN7 and PN12 pups but blocked learning in PN23 pups. 14C 2-deoxyglucose (2-DG) autoradiography indicated enhanced olfactory bulb activity in PN7 and PN12 pups with odor preference and avoidance learning. The odor aversion in weanling aged (PN23) pups resulted in enhanced amygdala activity in Paired odor-LiCl pups, but not if they were nursing. Thus, the neural circuit supporting malaise-induced aversions changes over development, indicating that similar infant and adult-learned behaviors may have distinct neural circuits.     

Social cues modulate the representations underlying cross-situational learning

Because children hear language in environments that contain many things to talk about, learning the meaning of even the simplest word requires making inferences under uncertainty. A cross-situational statistical learner can aggregate across naming events to form stable word-referent mappings, but this approach neglects an important source of information that can reduce referential uncertainty: social cues from speakers (e.g., eye gaze). In four large-scale experiments with adults, we tested the effects of varying referential uncertainty in cross-situational word learning using social cues. Social cues shifted learners away from tracking multiple hypotheses and towards storing only a single hypothesis (Experiments 1 and 2). In addition, learners were sensitive to graded changes in the strength of a social cue, and when it became less reliable, they were more likely to store multiple hypotheses (Experiment 3). Finally, learners stored fewer word-referent mappings in the presence of a social cue even when given the opportunity to visually inspect the objects for the same amount of time (Experiment 4). Taken together, our data suggest that the representations underlying cross-situational word learning of concrete object labels are quite flexible: In conditions of greater uncertainty, learners store a broader range of information.     

On the cognitive processes underlying contextual interference and observational learning

The main goal of the present study was to determine whether observation of an unskilled model learning a timing task enables the observer to develop a cognitive representation of the task similar to the one acquired through physical practice (Adams, 1986; Bandura, 1977; Lee & White, 1990). To reach that goal, we tested whether a contextual interference effect would be obtained in a retention test of subjects who had observed an individual practicing three variations of a timing task under a random or a blocked schedule of practice. Similar patterns of results in an immediate retention test were found following observation and physical practice. This suggests that observation indeed engaged the observers in the same type of cognitive activities as did physical practice. Moreover, a schedule of practice made up of 100% physical practice led to improved learning compared with a schedule of practice made up of 50% observation followed by 50% physical practice. This suggests that learning is enhanced more by numerous implementations of a motor program than by its mere construction or retrieval.     

Inter-individual variability in metacognitive ability for visuomotor performance and underlying brain structures

Metacognition refers to the ability to discriminate between one’s own correct and incorrect decisions. The neurobiological underpinnings of metacognition have mainly been studied in perceptual decision-making. Here we investigated whether differences in brain structure predict individual variability in metacognitive sensitivity for visuomotor performance. Participants had to draw straight trajectories toward visual targets, which could unpredictably deviate around detection threshold, report such deviations when detected, and rate their confidence level for such reports. Structural brain MRI analyses revealed that larger gray-matter volume (GMV) in the left middle occipital gyrus, left medial parietal cortex, and right postcentral gyrus predicted higher deviation detection sensitivity. By contrast, larger GMV in the right prefrontal cortex but also right anterior insula and right fusiform gyrus predicted higher metacognitive sensitivity. These results extend past research by linking metacognitive sensitivity for visuomotor behavior to brain areas involved in action agency (insula), executive control (prefrontal cortex) and vision (fusiform).     

Connectionist models of social learning: a case of learning by observing a simple task]

This article proposes a connectionist model of the social learning theory developed by Bandura (1977). The theory posits that an individual in an interactive situation is capable of learning new behaviours merely by observing them in others. Such learning is acquired through an initial phase in which the individual memorizes what he has observed (observation phase), followed by a second phase where he puts the recorded observations to use as a guide for adjusting his own behaviour (reproduction phase). We shall refer to the two above-mentioned phases to demonstrate that it is conceivable to simulate learning by observation otherwise than through the recording of perceived information using symbolic representation. To this end we shall rely on the formalism of ecological neuron networks (Parisi, Cecconi, & Nolfi, 1990) to implement an agent provided with the major processes identified as essential to learning through observation. The connectionist model so designed shall implement an agent capable of recording perceptive information and producing motor behaviours. The learning situation we selected associates an agent demonstrating goal-achievement behaviour and an observer agent learning the same behaviour by observation. Throughout the acquisition phase, the demonstrator supervises the observer's learning process based on association between spatial information (input) and behavioural information (output). Representation thus constructed then serves as an adjustment guide during the production phase, involving production by the observer of a sequence of actions which he compares to the representation stored in distributed form as constructed through observation. An initial simulation validates model architecture by confirming the requirement for both phases identified in the literature (Bandura, 1977) to simulate learning through observation. The representation constructed over the observation phase evidences acquisition of observed behaviours, although this phase alone is not sufficient to ensure accurate reproduction and must be made functional through the production phase (Deakin & Proteau, 2000). Results obtained through a second simulation replicate those produced by Bandura & Jeffery (1973), who observed that the individual tested following the retention phase recalled recorded information better than he realized in the production phase. The outcome of a third simulation shows that, when performing the transfer task, agents performed the task all the more effectively when they were required to learn a simple path which facilitated knowledge transfer to an adjacent situation. New explanatory assumptions of the mechanics of learning through observation may be produced through OLEANNet. Thus, observed deterioration between memorization and production is caused by successive approximations which occur in the acquisition phase then in the production phase. Further, depending on the type of learning undergone by agents, use of representation as a production guide induces a more or less stringent constraint in the approximation of actual behaviour. This results, during the transfer task, in the ability to effectively generalize acquired knowledge where such knowledge is not specifically related to the task at hand. In conclusion, connectionist model architecture appears valid for modeling learning through observation as defined by Bandura (1977). However, certain limitations appear during implementation, especially in terms of the observed behaviour's availability and the planning of produced behaviours that future developments are liable to counter.     

Retrospective revaluation as simple associative learning

Backward blocking, unovershadowing, and backward conditioned inhibition are examples of retrospective revaluation phenomena that have been suggested to involve more than simple associative learning. Models of these phenomena have thus used additional concepts, for example, appealing to attentional effects or more elaborate learning mechanisms. The author shows that a suitable representation of stimuli, paired with a careful analysis of the discriminations faced by animals, leads to an account of these and other phenomena in terms of a simple elemental model of associative learning, with essentially the same learning mechanism as the R. A. Rescorla and A. R. Wagner (1972) model. The author concludes with a discussion of some implications for theories of learning.