Andrea L. Patalano

Alternative strategies of categorization.

Psychological studies of categorization often assume that all concepts are of the same general kind, and are operated on by the same kind of categorization process. In this paper, we argue against this unitary view, and for the existence of qualitatively different categorization processes. In particular, we focus on the distinction between categorizing an item by: (a) applying a category-defining rule to the item vs. (b) determining the similarity of that item to remembered exemplars of a category. We begin by characterizing rule application and similarity computations as strategies of categorization. Next, we review experimental studies that have used artificial categories and shown that differences in instructions or time pressure can lead to either rule-based categorization or similarity-based categorization. Then we consider studies that have used natural concepts and again demonstrated that categorization can be done by either rule application or similarity calculations. Lastly, we take up evidence from cognitive neuroscience relevant to the rule vs. similarity issue. There is some indirect evidence from brain-damaged patients for neurological differences between categorization based on rules vs. that based on similarity (with the former involving frontal regions, and the latter relying more on posterior areas). For more direct evidence, we present the results of a recent neuroimaging experiment, which indicates that different neural circuits are involved when people categorize items on the basis of a rule as compared with when they categorize the same items on the basis of similarity.

PET evidence for multiple strategies of categorization

It is widely held that people use multiple strategies to categorize their experiences in the world. We conducted a pair of neuroimaging experiments to identify the neural correlates of two of these strategies— rule application and exemplar similarity. Participants were instructed to perform either a ruleor an exemplar-based categorization task while changes in cerebral blood flow were measured using positron emission tomography. Patterns of neural activity were consistent with the predictions of cognitive models of rule- versus exemplar-based categorization and with existing neuroscience data. The identification of strategy-specific neural patterns offers future researchers a diagnostic tool for assessing strategy use in other situations.

Memory for impasses during problem solving

Three experiments were conducted to investigate the relative memorability of solved versus unsolved problems in long-term memory. In each experiment, subjects worked on a set of potentially solvable word problems, with the time spent on each problem held constant. Problem memorability was then measured with a free-recall task. In Experiment 1, in which a majority of problems were solved, unsolved problems were better remembered. In Experiments 2 and 3, we expanded on these results by manipulating problem difficulty and thus the ratio of solved to unsolved problems. When unsolved problems were as frequent as or more frequent than solved problems, no memory differences were found. Across all three experiments, the ratio of solved to unsolved problems was found to be a significant predictor of unsolved-problem memorability, but was not significantly related to the memorability of solved problems. The results illustrate that when impasses in problem solving are infrequent, they are more available in memory than are solved problems. It is speculated that this memory phenomenon may facilitate the recognition of opportunities to return to problems that have been terminated short of solution.

Opportunism in Memory: Preparing for Chance Encounters

Recognizing opportunities to achieve pending goals is an important cognitive ability. But when and how do we recognize that a current situation is especially suited to resuming a past goal? The predictive encoding model suggests pending goals are encoded into memory in association with anticipated environmental features. Optimally, these features are (a) necessary for successful goal satisfaction, (b) distinctive preconditions for expecting a plan to achieve the goal, and (c) described so as to be readily identified in the environment. Later, ordinary perception of features in the environment leads to automatic recognition of opportunities already prepared in memory. Evidence from experimental studies supports this theory, and demonstrates that general preparation can produce apparently novel opportunism. These findings suggest ways to facilitate the recognition of opportunities to satisfy pending goals.

Minimal-group membership influences children's responses to novel experience with group members

Children, like adults, tend to prefer ingroup over outgroup individuals, but how this group bias affects childrens processing of information about social groups is not well understood. In this study, 5- and 6-year-old children were assigned to artificial groups. They observed instances of ingroup and outgroup members behaving in either a positive (egalitarian) or a negative (stingy) manner. Observations of positive ingroup and negative outgroup behaviors reliably reduced childrens liking of novel outgroup members, while observations of negative ingroup and positive outgroup behaviors had little effect on liking ratings. In addition, children successfully identified the more generous group only when the ingroup was egalitarian and the outgroup stingy. These data provide compelling evidence that children treat knowledge of and experiences with ingroups and outgroups differently, and thereby differently interpret identical observations of ingroup versus outgroup members.

The role of category coherence in experience-based prediction

Both real-world category knowledge and instance-based sample data are often available as sources of inductive inference. In three experiments using natural social categories, we test the influence of general category knowledge on the use of category instances to make property inductions both to other category members and to others in the population. We find that a category’s coherence—the extent to which its features are interrelated through prior knowledge (Murphy & Medin, 1985)—influences inductions positively to new category members and negatively to the population. This effect of coherence is strongest with small as compared with large samples of instances. The results are interpreted from both similarity and explanation-based perspectives.

The role of numeracy and approximate number system acuity in predicting value and probability distortion.

It is well documented that individuals distort outcome values and probabilities when making choices from descriptions, and there is evidence of systematic individual differences in distortion. In the present study, we investigated the relationship between individual differences in such distortions and two measures of numerical competence, numeracy and approximate number system (ANS) acuity. Participants indicated certainty equivalents for a series of simple monetary gambles, and data were used to estimate individual-level value and probability distortion, using a cumulative prospect theory framework. We found moderately strong negative correlations between numeracy and value and probability distortion, but only weak and non-statistically reliable correlations between ANS acuity and distortions. We conclude that low numeracy contributes to number distortion in decision making, but that approximate number system acuity might not underlie this relationship.

The influence of category coherence on inference about cross-classified entities

A critical function of categories is their use in property inference (Heit, 2000). However, one challenge to using categories in inference is that most entities in the world belong to multiple categories (e.g., Fido could be a dog, a pet, a mammal, or a security system). Building on Patalano, Chin-Parker, and Ross (2006), we tested the hypothesis that category coherence (the extent to which category features go together in light of prior knowledge) influences the selection of categories for use in property inference about cross-classified entities. In two experiments, we directly contrasted coherent and incoherent categories, both of which included cross-classified entities as members, and we found that the coherent categories were used more readily as the source of both property transfer and property extension. We conclude that category coherence, which has been found to be a potent influence on strength of inference for singly classified entities (Rehder & Hastie, 2004), is also central to category use in reasoning about novel cross-classified ones.

Partition dependence in consumer choice: Perceptual groupings do not reliably shape decisions

The partitioning of options into arbitrary categories has been shown to influence decisions about allocating choices or resources among those options; this phenomenon is called partition dependence. While we do not call into question the validity of the partition dependence phenomenon in the present work, we do examine the robustness of one of the experimental paradigms reported by Fox, Ratner, and Lieb (Journal of Experimental Psychology: General, 134, 538–551, 2005, Study 4). In three experiments (N = 300) conducted here, participants chose from a menu of perceptually partitioned options (varieties of candy distributed across bowls). We found no clear evidence of partition dependent choice in children (Experiment 1) and no evidence at all of partition dependence in adults’ choices (Experiments 1–3). This was true even when methods were closely matched to those of Fox et al.’s Study 4 (Experiment 3). We conclude that the candy-bowl choice task does not reliably elicit partition dependence and propose possible explanations for the discrepancy between these findings and prior reports. Future work will explore the conditions under which partition dependence in consumer choice does reliably arise.

Partition dependence in development: Are children’s decisions shaped by the arbitrary grouping of options?

The grouping of options into arbitrary categories influences adults’ decisions about allocating choices or resources among those options; this is called “partition dependence.” Partition dependence has been demonstrated in a wide range of contexts in adults and is often presented as a technique for designing choice architectures that nudge people towards better decisions. Whether children also make partition dependent decisions is unknown, as are potential patterns of developmental change. In this experiment (N = 159), we examined whether children exhibit partition dependence using a novel resource allocation task. This novel task, distributing food tokens to zoo animals, did elicit partition dependence in our developmental sample. Both older children (ages 7-10 years) and younger children (ages 3-6 years) made partition dependent allocations, and younger children exhibited a larger partition dependence effect than did older children. This work provides the first evidence that children’s decisions, like adults’, are influenced by the arbitrary grouping of the options, and suggests that younger children may be more susceptible to this influence, at least in the context explored here.