Automatic Learning of the Frequencies of Occurrence of Stimulus Features

Whether people automatically learn the relative frequency of occurrence of stimulus features when they attend to instances of a concept was investigated. College students viewed instances of a concept defined by a conjunction of two stimulus features. The frequency of stimulus features was varied systematically. The instructions or orienting task given to subjects and the rate of stimulus presentation during learning were manipulated. Following learning, subjects estimated the frequencies of stimulus features. To measure concept learning, a recognition test (consisting of old instances, new instances, and new noninstances) and a definition test were given. Contrary to the view that feature frequencies are learned automatically, instructions and rate of presentation both affected subjects' knowledge of features occurring with high frequency. These plus other findings in the literature suggest that feature-frequency learning is neither automatic nor effortful. An alternative to the dichotomy of automatic versus effortful processes is discussed.