A neuropsychological theory is proposed that assumes category learning is a competition between separate verbal and implicit (i.e., procedural-learning-based) categorization systems. The theory assumes that the caudate nucleus is an important component of the implicit system and that the anterior cingulate and prefrontal cortices are critical to the verbal system. In addition to making predictions for normal human adults, the theory makes specific predictions for children, elderly people, and patients suffering from Parkinson's disease, Huntington's disease, major depression, amnesia, or lesions of the prefrontal cortex. Two separate formal descriptions of the theory are also provided. One describes trial-by-trial learning, and the other describes global dynamics. The theory is tested on published neuropsychological data and on category learning data with normal adults.

This is the manuscript that was published, with only minor copy-editing alterations, as: Haidt, J. (2001). The emotional dog and its rational tail: A social intuitionist approach to moral judgment. Psychological Review. 108, 814-834 Copyright 2001, American Psychological Association To obtain a reprint of the final type-set article, please go through your library’s journal services, or contact the author directly Research on moral judgment has been dominated by rationalist models, in which moral judgment is thought to be caused by moral reasoning. Four reasons are given for considering the hypothesis that moral reasoning does not cause moral judgment; rather, moral reasoning is usually a post-hoc construction, generated after a judgment has been reached. The social intuitionist model is presented as an alternative to rationalist models. The model is a social model in that it de-emphasizes the private reasoning done by individuals, emphasizing instead the importance of social and cultural influences. The model is an intuitionist model in that it states that moral judgment is generally the result of quick, automatic evaluations (intuitions). The model is more consistent than rationalist models with recent findings in social, cultural, evolutionary, and biological psychology, as well as anthropology and primatology. Author notes

This review proposes that implicit learning processes are the cognitive substrate of social intuition. This hypothesis is supported by (a) the conceptual correspondence between implicit learning and social intuition (nonverbal communication) and (b) a review of relevant neuropsychological (Huntington's and Parkinson's disease), neuroimaging, neurophysiological, and neuroanatomical data. It is concluded that the caudate and putamen, in the basal ganglia, are central components of both intuition and implicit learning, supporting the proposed relationship. Parallel, but distinct, processes of judgment and action are demonstrated at each of the social, cognitive, and neural levels of analysis. Additionally, explicit attempts to learn a sequence can interfere with implicit learning. The possible relevance of the computations of the basal ganglia to emotional appraisal, automatic evaluation, script processing, and decision making are discussed. These "feelings " have an efficiency of operation which it is impossi-ble for thought to match. Even our most highly intellectualized operations depend upon them as a "fringe " by which to guide our inferential movements. They give us our sense of rightness and wrongness, of what to select and emphasize and follow up, and what

Can we learn without awareness? Although this issue has been extensively explored through studies of implicit learning, there is currently no agreement about the extent to which knowledge can be acquired and projected onto performance in an unconscious way. The controversy, like that surrounding implicit memory, seems to be at least in part attributable to unquestioned acceptance of the unrealistic assumption that tasks are process-pure, that is, that a given task exclusively involves either implicit or explicit knowledge. Methods such as the Process Dissociation Procedure (PDP, Jacoby, 1991) have been developed to overcome the conceptual limitations of the process purity assumption, but have seldom been used in the context of implicit learning research. In this paper, we show how the PDP can be applied to a free generation task so as to disentangle explicit and implicit sequence learning. Our results indicate that participants who are denied preparation to the next stimulus nevertheless exhibit knowledge of the sequence through their reaction time performance despite remaining unable (1) to project this knowledge in a recognition task and (2) to refrain from expressing their knowledge when specifically instructed to do so. These findings provide strong evidence that sequence learning can be unconscious.

Children's (Grades 1 to 5) implicit learning of French orthographic regularities were investigated through nonword judgment (Experiments 1 and 2) and completion (Experiments 3a and 3b) tasks. Children were increasingly sensitive to (a) the frequency of double consonants (Experiments 1, 2 and 3a), (b) the fact that vowels can never be doubled (Experiment 2) and (c) the legal position of double consonants (Experiments 2 and 3b). The later effect transferred to never doubled consonants, although with a decrement in performance. Moreover, this decrement persisted without any trend towards fading even after the massive amounts of experience provided by years of practice. This result runs against the idea that transfer to novel material is indicative of abstract rule-based knowledge, and suggests instead the action of mechanisms sensitive to the statistical properties of the material. A connectionist model is proposed as an instantiation of such mechanisms.

The authors investigated the extent to which touch, vision, and audition mediate the processing of statistical regularities within sequential input. Few researchers have conducted rigorous comparisons across sensory modalities; in particular, the sense of touch has been virtually ignored. The current data reveal not only commonalities but also modality constraints affecting statistical learning across the senses. To be specific, the authors found that the auditory modality displayed a quantitative learning advantage compared with vision and touch. In addition, they discovered qualitative learning biases among the senses: Primarily, audition afforded better learning for the final part of input sequences. These findings are discussed in terms of whether statistical learning is likely to consist of a single, unitary mechanism or multiple, modality-constrained ones. The world is temporally bounded: Events do not occur all at once but rather are distributed in time. Therefore, it is crucial for organisms to be able to encode and represent temporal order information. One potential method for encoding temporal order is to learn the statistical relationships of elements within sequential input. This process appears to be important in a diverse set of learning situations, including speech segmentation (Saffran, Newport, & Aslin, 1996), learning orthographic regularities of written words (Pacton, Perruchet, Fayol, & Cleeremans, 2001), visual processing (Fiser & Aslin, 2002), visuomotor learning (e.g., serial reaction time tasks; Cleeremans, 1993) and nonlinguistic, auditory

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Evidence for unconscious learning has typically been based on dissociations between direct and indirect tests of learning. Because of some inherent problems with dissociation logic, we applied the logic of opposition to 2 artificial grammar learning experiments. In Experiment 1, participants were exposed to 2 different sets of letter strings, generated from 2 different grammars, and later rated test strings for grammaticality with either in concert (rate "grammatical" strings consistent with either structure) or opposition (rate "grammatical" only strings from 1 of the structures) instructions. Manipulating response deadline affected controlled, but not automatic influences. In Experiment 2, after similar training, a source monitoring test was administered from which the in concert and opposition conditions were derived. The test indicated that varying the retention interval affected controlled, but not automatic influences. The results are discussed in terms of awareness, knowledge representation and metacognitive processing. Beyond Dissociation Logic: Evidence for Controlled and Automatic Influences in Artificial Grammar Learning The study of various types of unconscious influence on behavior is one of the most hotly debated and widely researched topics in psychology. Traditionally, Freudian psychologists have assumed that unconscious influences stem from repressed sexual and aggressive urges and fantasies. In contrast, modern researchers in cognitive psychology assume that unconscious influences are broader and not necessarily linked to repression. For example, people might treat a mundane, previously encountered stimulus differently from a novel one, despite the fact that they do not consciously recall having encountered it before (e.g., they may claim to like an ol...

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Implicit learning is generally characterized as learning that proceeds both unintentionally and unconsciously. Here are some examples: 1 Reber (1967), who coined the term ‘implicit learning’, asked participants to study a series of letter strings such as VXVS for a few seconds each. Then he told them that these strings were all constructed according to a particular set of rules (that is, a grammar; see Figure 8.1) and that in the test phase they would see some new strings and would have to decide which ones conformed to the same rules and which ones did not. Participants could make these decisions with better-than-chance accuracy but had little ability to describe the rules. For example, participants could not recall correctly which letters began and ended the strings. Reber described his results as a ‘peculiar combination of highly efficient behavior with complex stimuli and almost complete lack of verbalizable knowledge about them ’ (p. 859). 2 In the 1950s, a number of studies asked people to generate words ad libitum and established that the probability with which they would produce, say, plural nouns was increased if each such word was reinforced by the experimenter saying ‘umhmm ’ (e.g. Greenspoon, 1955). This result occurred in subjects apparently unable to report the reinforcement contingency. 3 Svartdal (1991) presented participants with brief trains of between 4 and 17 auditory clicks. Participants immediately had to press a response button exactly the same number of times and were instructed that feedback would be presented when the number of presses matched the number of clicks. In fact, though, feedback was contingent on speed of responding: for some