Proceedings of the Annual Meeting of the Cognitive Science Society

In this paper we examine the theoretical and empirical work in psychology that is relevant to Hanson's (1958) and Kuhn's (1962) arguments for the theory ladenness of observation. W e conclude that the data support the Hanson and Kuhn position against the earlier positivist views that sensory data provides an completely objective basis for deciding between rival scientific theories. However, the data also suggest that top-down influences on perception are only strong when the incoming sensory input is weak or ambiguous. Thus, in cases where the bottom-up sensory evidence is strong and unambiguous, there is Uttle evidence that theory can override observation, and so the data do not support the strong form of the theory-laden position that is sometimes attributed to Hanson and Kuhn. In addition we argue that philosophical work on theory-ladenness has focused too narrowly on the issue of perception and ignored attention and memory. Our analysis suggests the need for a much broader view of the mental processes involved in doing science, and our synthesis of the empirical literature shows the influence of top-down schemata on perception, attention, comprehension, and memory. This top-down, bottom-up synthesis seems to us to provide a satisfying resolution of the controversy over the theory-ladenness of perception.