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K J Holyoak

Publications and source records attributed to K J Holyoak.

26 records · Page 2Linked to original sources
PubMed1986

Distributional expectations and the induction of category structure.

Previous research on how categories are learned from observation of exemplars has largely ignored the possible role of prior expectations concerning how exemplars will be distributed. The experiments reported here explored this issue by presenting subjects with category-learning tasks in which the distributions of exemplars defining the categories were varied. In Experiments 1 and 2 the distributional form of a category was found to affect speed of learning. Learning was faster when a category's distribution was normal than when it was multimodal. Also, subjects in the early stages of learning a multimodal category responded as if it were unimodal. These results suggested that subjects enter category-learning tasks with expectations of unimodal, possibly normal, distributions of exemplars. Experiments 3 and 4 attempted to manipulate subjects' prior expectations by varying the distribution of exemplars in the first of two consecutive category-learning tasks. Learning a multimodal category was influenced by the shape of a previously learned distribution and was facilitated when the earlier distribution was either multimodal or skewed, rather than normal. These results are interpreted as support for a dual-process model of category learning that incorporates the effects of prior expectations concerning exemplar distributions.

Adolescent↗
PubMed1984

Induction of category distributions: a framework for classification learning.

We present a framework for classification learning that assumes that learners use presented instances (whether labeled or unlabeled) to infer the density functions of category exemplars over a feature space and that subsequent classification decisions employ a relative likelihood decision rule based on these inferred density functions. A specific model based on this general framework, the category density model, was proposed to account for the induction of normally distributed categories either with or without error correction or provision of labeled instances. The model was implemented as a computer simulation. Results of five experiments indicated that people could learn category distributions not only without error correction, but without knowledge of the number of categories or even that there were categories to be learned. These and other findings dictated a more general learning model that integrated distributional representations based on both parametric descriptions and stored instances.

Decision Making↗
PubMed1984

Development of analogical problem-solving skill.

3 experiments were performed to assess children's ability to solve a problem by analogy to a superficially dissimilar situation. Preschoolers and fifth and sixth graders were asked to solve a problem that allowed multiple solutions. Some subjects were first read a story that included an analogous problem and its solution. When the mapping between the relations involved in the corresponding solutions was relatively simple, and the corresponding instruments were perceptually and functionally similar, even preschoolers were able to use the analogy to derive a solution to the transfer problem (Experiment 1). Furthermore, salient similarity of the instruments was neither sufficient (Experiment 2) nor necessary (Experiment 3) for success by preschool subjects. When the story analog mapped well onto the transfer problem, 4-year-olds were often able to generate a solution that required transformation of an object with little perceptual or semantic similarity to the instrument used in the base analog (Experiment 3). The older children used analogies in a manner qualitatively similar to that observed in comparable studies with adults (Experiment 1), whereas the younger children exhibited different limitations.

Child↗
PubMed1981

A positional discriminability model of linear-order judgments.

The process of judging the relative order of stimuli in a visual array was investigated in three experiments. In the basic paradigm, a linear array of six colored lines was presented briefly, and subject decided which of two target lines was the leftmost or rightmost (Experiment 1). The target lines appeared in all possible combinations of serial positions and reaction time (RT) was measured. Distance and semantic congruity effects were obtained, as well as a bowed serial position function. The RT pattern resembled that observed in comparable studies with memorized linear orderings. The serial position function was flattened when the background lines were homogeneously dissimilar to the target lines (Experiment 2). Both a distance effect and bowed serial position functions were obtained when subjects judged which of two target lines was below a black bar cue (Experiment 3). The results favored and analog positional discriminability model over a serial ends-inward scanning model. The positional discriminability model was proposed as a "core model" for the processes involved in judging relative order or magnitude in the domains of memory and perception.

Color Perception↗