CiteULike: Group: Glimcher_Lab - with tag language

Free-ranging rhesus monkeys spontaneously individuate and enumerate small numbers of non-solid portions.

Justin N Wood — 2007-04-03T16:00:10-00:00

Cognition (20 March 2007)

Fundamental questions in cognitive science concern the origins and nature of the units that compose visual experience. Here, we investigate the capacity to individuate and store information about non-solid portions, asking in particular whether free-ranging rhesus monkeys (Macaca mulatta) quantify portions of a non-solid substance presented in discrete pouring actions. When presented with portions of carrot pieces poured from a cup into opaque boxes, rhesus picked the box with the greatest number of portions for comparisons of 1 vs. 2, 2 vs. 3, and 3 vs. 4, but not for comparisons of 4 vs. 5 and 3 vs. 6. Additional experiments indicate that rhesus based their decisions on both the number of portions and the total amount of food. These results show that the capacity to individuate non-solid portions is not unique to humans, and does not depend on structures of natural language. Further, the fact that rhesus' ability to represent non-solid portions is constrained by the same 4-item limit typically ascribed to the system of parallel individuation that operates over solid objects suggests that the visual system recruits common working memory processes for retaining information about solid objects and non-solid portions. We discuss our results with respect to theories of visual processing, as well as to the role that the human language faculty may have played in both the evolution and development of quantification.

The Role of the Striatum in Processing Language Rules: Evidence from Word Perception in Huntington's Disease

Marc Teichmann — 2007-05-16T17:25:36-00:00

J. Cogn. Neurosci., Vol. 18, No. 9. (1 September 2006), pp. 1555-1569.

On the assumption that linguistic faculties reflect both lexical storage in the temporal cortex and combinatorial rules in the striatal circuits, several authors have shown that striatal-damaged patients are impaired with conjugation rules while retaining lexical knowledge of irregular verbs [Teichmann, M., Dupoux, E., Kouider, S., Brugieres, P., Boisse, M. F., Baudic, S., Cesaro, P., Peschanski, M., & Bachoud-Levi, A. C. (2005). The role of the striatum in rule application. The model of Huntington's disease at early stage. Brain, 128, 1155-1167; Ullman, M. T., Corkin, S., Coppola, M., Hickok, G., Growdon, J. H., Koroshetz, W. J., & Pinker, S. (1997). A neural dissociation within language: Evidence that the mental dictionary is part of declarative memory, and that grammatical rules are processed by the procedural system. Journal of Cognitive Neuroscience, 9, 266-276]. Yet, such impairment was documented only with explicit conjugation tasks in the production domain. Little is known about whether it generalizes to other language modalities such as perception and whether it refers to implicit language processing or rather to intentional rule operations through executive functions. We investigated these issues by assessing perceptive processing of conjugated verb forms in a model of striatal dysfunction, namely, in Huntington's Disease (HD) at early stages. Rule application and lexical processes were evaluated in an explicit task (acceptability judgments on verb and nonword forms) and in an implicit task (lexical decision on frequency-manipulated verb forms). HD patients were also assessed in executive functions, and striatal atrophy was evaluated with magnetic resonance imaging (bicaudate ratio). Results from both tasks showed that HD patients were selectively impaired for rule application but lexical abilities were spared. Bicaudate ratios correlated with rule scores on both tasks, whereas executive parameters only correlated with scores on the explicit task. We argue that the striatum has a core function in linguistic rule application generalizing to perceptive aspects of morphological operations and pertaining to implicit language processes. In addition, we suggest that the striatum may enclose computational circuits that underpin explicit manipulation of regularities.

Performance Feedback Drives Caudate Activation in a Phonological Learning Task

Elizabeth Tricomi — 2007-05-16T17:24:38-00:00

J. Cogn. Neurosci., Vol. 18, No. 6. (1 June 2006), pp. 1029-1043.

Adults have difficulty discriminating nonnative phonetic contrasts, but under certain circumstances training can lead to improvement in this ability. Despite the ubiquitous use of performance feedback in training paradigms in this and many other domains, the mechanisms by which feedback affects learning are not well understood. In this event-related functional magnetic resonance imaging study, we examined how performance feedback is processed during perceptual learning. Thirteen Japanese speakers for whom the English phonemes [r] and [l] were nondistinct performed an identification task of the words "road" and "load" that has been shown to be effective in inducing learning only when performance feedback is present. Each subject performed alternating runs of training with and without feedback, followed by performance of a card-guessing task with monetary reward and punishment outcomes. We found that the caudate nucleus was more robustly activated bilaterally when performing the perceptual identification task with feedback than without feedback, and the right caudate nucleus also showed a differential response to positive and negative feedback. Moreover, using a within-subjects design, we found that the caudate nucleus also showed a similar activation pattern to monetary reward and punishment outcomes in the card-guessing task. These results demonstrate that the caudate responds to positive and negative feedback during learning in a manner analogous to its processing of extrinsic affective reinforcers and indicate that this region may be a critical moderator of the influence of feedback on learning. These findings impact our broader understanding of the mechanisms underlying nondeclarative learning and language acquisition.

The faculty of language: what's special about it?

S Pinker — 2005-02-26T20:46:08-00:00

Cognition, Vol. 95, No. 2. (March 2005), pp. 201-236.

We examine the question of which aspects of language are uniquely human and uniquely linguistic in light of recent suggestions by Hauser, Chomsky, and Fitch that the only such aspect is syntactic recursion, the rest of language being either specific to humans but not to language (e.g. words and concepts) or not specific to humans (e.g. speech perception). We find the hypothesis problematic. It ignores the many aspects of grammar that are not recursive, such as phonology, morphology, case, agreement, and many properties of words. It is inconsistent with the anatomy and neural control of the human vocal tract. And it is weakened by experiments suggesting that speech perception cannot be reduced to primate audition, that word learning cannot be reduced to fact learning, and that at least one gene involved in speech and language was evolutionarily selected in the human lineage but is not specific to recursion. The recursion-only claim, we suggest, is motivated by Chomsky's recent approach to syntax, the Minimalist Program, which de-emphasizes the same aspects of language. The approach, however, is sufficiently problematic that it cannot be used to support claims about evolution. We contest related arguments that language is not an adaptation, namely that it is "perfect," non-redundant, unusable in any partial form, and badly designed for communication. The hypothesis that language is a complex adaptation for communication which evolved piecemeal avoids all these problems.