Abstract

The issue of the theory-ladenness of observation has long troubled philosophers of science, largely because it seems to threaten the objectivity of science. However, the way in which prior beliefs influence the perception of data is in part an empirical issue that can be investigated by cognitive psychology. This point is illustrated through an experimental analogue of scientific data-interpretation tasks in which subjects judging the covariation between personality variables based their judgments on pure data, their theoretical intuitions about the variables, or both data and prior theoretical beliefs. Results showed that the perceived magnitude of correlations was greatest when subjects relied solely on theoretical intuitions; that data-based judgments were drawn in the direction of those prior beliefs; but that exposure to data nonetheless moderated the strength of the prior theories. In addition, prior beliefs were found to influence judgments only after a brief priming interval, suggesting that subjects needed time to retrieve their theoretical intuitions from memory. These results suggest ways to investigate the processes mediating theory-laden observation, and, contrary to the fears of positivist philosophers, imply that the theory-ladenness of observation does not entail that theoretical beliefs are immune to data