Rick Dale

Graded motor responses in the time course of categorizing atypical exemplars

The time course of categorization was investigated in four experiments, which revealed graded competitive effects in a categorization task. Participants clicked one of two categories (e.g.,mammal orfish) in response to atypical or typical exemplars (e.g.,whale orcat) in the form of words (Experiments 1 and 2) or pictures (Experiments 3 and 4). Streamingx, y coordinates of mouse movement trajectories were recorded. Normalized mean trajectories revealed a graded competitive process: Atypical exemplars produced trajectories with greater curvature toward the competing category than did typical exemplars. The experiments contribute to recent examination of the time course of categorization and carry implications for theories of representation in cognitive science.

The role of sequential learning in language evolution: computational and experimental studies

After having been plagued for centuries by unfounded speculations, the study of language evolution is now emerging as an area of legitimate scientific inquiry. Early conjectures about the origin and evolution of language suffered from a severe lack of empirical evidence to help rein in proposed theories. This led to outlandish claims such as the idea that Chinese was the original ur-language of humankind, surviving the biblical flood because of Noah and his family (Webb, 1669, cited in Aitchison, 1998). Or, the suggestion that humans have learned how to sing and speak from the birds in the same way as they would have learned how to weave from spiders (Burnett, 1773, cited in Aitchison, 1998). Given this state of the art, it was perhaps not surprising that the influential Societe Linguistique de Paris in 1866 imposed a ban on papers discussing issues related to language origin and evolution, and effectively excluded such theorizing from the scientific discourse.

From apples and oranges to symbolic dynamics: a framework for conciliating notions of cognitive representation

We introduce symbolic dynamics to cognitive scientists with the aim of furthering constructive debate on representation. Symbolic dynamics is a mathematical framework in which both continuous and discrete states of a system can be considered jointly. We discuss a number of theoretical implications this framework has for cognitive science, and offer some consideration of the way in which it might be employed for comparing or conciliating discrete and continuous representational theories. Symbolic dynamics may thus serve as a common, level playing field for debate in theories of cognitive representation.