Biomedical subjects

E Heit

Publications and source records attributed to E Heit.

9 recordsLinked to original sources

PubMed2001

Diversity-based reasoning in children.

One of the hallmarks of inductive reasoning by adults is the diversity effect, namely that people draw stronger inferences from a diverse set of evidence than from a more homogenous set of evidence. However, past developmental work has not found consistent diversity effects with children age 9 and younger. We report robust sensitivity to diversity in children as young as 5, using everyday stimuli such as pictures of objects with people. Experiment 1 showed the basic diversity effect in 5- to 9-year-olds. Experiment 2 showed that, like adults, children restrict their use of diversity information when making inferences about remote categories. Experiment 3 used other stimulus sets to overcome an alternate explanation in terms of sample size rather than diversity effects. Finally, Experiment 4 showed that children more readily draw on diversity when reasoning about objects and their relations with people than when reasoning about objects' internal, hidden properties, thus partially explaining the negative findings of previous work. Relations to cross-cultural work and models of induction are discussed.

Adult↗

PubMed2001

Putting together prior knowledge, verbal arguments, and observations in category learning.

Two experiments addressed the novel issue of how people incorporate verbal arguments into category learning. In Experiment 1, at the start of learning, subjects were given verbal arguments, which had an influence equivalent to a fixed number of category members. In Experiment 2, subjects learned under slower paced conditions, and it was found that both prior knowledge and arguments had multiple effects on categorization: a fixed initial influence plus selective weighting of new observations. The results supported the idea that verbally presented arguments can be treated in a similar manner as other forms of prior knowledge, from the perspective of applying models of categorization.

Adult↗

PubMed2000

Associative recognition: a case of recall-to-reject processing.

Two-process accounts of recognition memory assume that memory judgments are based on both a rapidly available familiarity-based process and a slower, more accurate, recall-based mechanism. Past experiments on the time course of item recognition have not supported the recall-to-reject account of the second process, in which the retrieval of an old item is used to reject a similar foil (Rotello & Heit, 1999). In three new experiments, using analyses similar to those of Rotello and Heit, we found robust evidence for recall-to-reject processing in associative recognition, for word pairs, and for list-discrimination judgments. Put together, these results have implications for two-process accounts of recognition.

Adult↗

PubMed2000

Properties of inductive reasoning.

This paper reviews the main psychological phenomena of inductive reasoning, covering 25 years of experimental and model-based research, in particular addressing four questions. First, what makes a case or event generalizable to other cases? Second, what makes a set of cases generalizable? Third, what makes a property or predicate projectable? Fourth, how do psychological models of induction address these results? The key results in inductive reasoning are outlined, and several recent models, including a new Bayesian account, are evaluated with respect to these results. In addition, future directions for experimental and model-based work are proposed.

Adult↗

PubMed1998

Influences of prior knowledge on selective weighting of category members.

Three experiments addressed how prior theories affect categorization, comparing the influence of theory-congruent versus theory-incongruent category members. Subjects observed descriptions of persons, some congruent with prior knowledge and some incongruent, then made transfer judgments. In Experiment 1, subjects were given a relatively long time to study each description, whereas in Experiment 2 study time was manipulated between subjects. In Experiment 3, learning was self-paced by each subject. It was found that, with enough study time, prior knowledge had 2 distinct influences. First, prior knowledge provided an initial representation, subsequently revised in light of new observations. Second, incongruent observations had more impact than congruent observations on categorization. In comparison, when study time was more limited, revision proceeded in a Bayesian manner, in that congruent and incongruent observations had equal impacts.

Adult↗

PubMed1996

The instantiation principle in natural categories.

According to the instantiation principle, the representation of a category includes detailed information about its diverse range of instances. Many accounts of categorisation, including classical and standard prototype theories, do not follow the instantiation principle, because they assume that detailed, exemplar-level information is filtered out of category representations. Nevertheless, the instantiation principle can be implemented in a wide class of models, including both exemplar and abstraction models. To assess the instantiation principle empirically, a parameter-free exemplar-based model of instantiation was applied to typicality judgments for 16 simple categories (e.g. mammal, beverage) and 14 complex categories (e.g. dangerous mammal) in four superordinates (animal, food, small animal, dangerous animal). Across three studies, the model did an excellent job of predicting mean typicality judgments (correlations generally above 0.9) and a good job of predicting standard deviations (fits generally from 0.6 to 0.9). In Study 3, predicting the skew of typicality distributions was successful as well (a fit of 0.87), and dropping atypical exemplars from the simulations degraded prediction. All of these results support the instantiation principle, indicating that subjects incorporate detailed information about category instances into their representations of categories.

Humans↗

PubMed1994

Similarity and property effects in inductive reasoning.

Three experiments investigated the proposal that inductive inferences about different properties depend on different measures of similarity. In Experiments 1 and 2, Ss were given the premise that a category of animals has some property and judged the probability that another category of animals also has that property. Ss made the strongest inferences when the kind of property (anatomical or behavioral) corresponded to the kind of similarity between the animal categories (anatomical or behavioral). These results cannot be explained in terms of a single measure of similarity underlying induction. In Experiment 3, Ss rated the similarity of animal pairs with respect to anatomy or behavior. Regression analyses showed that both behavioral and anatomical similarity influenced behavioral inferences, but only anatomical similarity influenced anatomical inferences.

Adult↗

PubMed1994

Models of the effects of prior knowledge on category learning.

When people learn about a new category, they are influenced by prior knowledge of other categories. In 5 experiments, subjects made categorization judgments after observing descriptions of persons from a location referred to as City W. In these experiments, prior knowledge as well as observations within City W were manipulated. The integration, weighting, and distortion models of categorization explain prior knowledge effects in different ways. The integration model, which assumes that categorization is influenced by prior examples from other categories, predicted the results of the experiments. It was found that the effect of prior knowledge was independent of the observed proportion of category membership in City W, that the prior knowledge effect was diminished with more observations, and that learning about City W affected subjects' judgments about the general population. The weighting and distortion models could not account for all of the results.

Humans↗

PubMed1993

An evaluation of the total similarity principle: effects of similarity on frequency judgments.

Memory models that embody the total similarity principle (e.g., Gillund & Shiffrin, 1984; Hintzman, 1988; Murdock, 1982; Ratcliff, 1990) assume that frequency judgments reflect the total similarity of a test item to stimuli that have been studied. In 4 experiments, subjects estimated the frequencies of target words that had been presented in the context of varying numbers of semantically similar words. In a fifth experiment, subjects made forced-choice relative frequency judgments. The results of these experiments supported 1 prediction of total similarity models: Presenting similar words will increase rather than decrease frequency judgments of target words. However, a second prediction of these models was not supported. In particular, similar-word presentations had no effect on the judged frequencies of target words that had not been shown.

Adult↗