Working memory does not dissociate between different perceptual categorization tasks

Working memory is crucial for many higher level cognitive functions, ranging from mental arithmetic to reasoning and problem solving. Likewise, the ability to learn and categorize novel concepts forms an indispensable part of human cognition. However, very little is known about the relationship between working memory and categorization. This article reports 2 studies that related people's working memory capacity (WMC) to their learning performance on multiple rule-based and information-integration perceptual categorization tasks. In both studies, structural equation modeling revealed a strong relationship between WMC and category learning irrespective of the requirement to integrate information across multiple perceptual dimensions. WMC was also uniformly related to people's ability to focus on the most task-appropriate strategy, regardless of whether or not that strategy involved information integration. Contrary to the predictions of the multiple systems view of categorization, working memory thus appears to underpin performance in both major classes of perceptual category-learning tasks.     

Speaker reliability guides children's inductive inferences about novel properties

Prior work shows that children can make inductive inferences about objects based on their labels rather than their appearance (Gelman, 2003). A separate line of research shows that children's trust in a speaker's label is selective. Children accept labels from a reliable speaker over an unreliable speaker (e.g., Koenig & Harris, 2005). In the current paper, we tested whether 3- and 5-year-old children attend to speaker reliability when they make inductive inferences about a non-obvious property of a novel artifact based on its label. Children were more likely to use a reliable speaker's label than an unreliable speaker's label when making inductive inferences. Thus, children not only prefer to learn from reliable speakers, they are also more likely to use information from reliable speakers as the basis for future inferences. The findings are discussed in light of the debate between a similarity-driven and a label-driven approach to inductive inferences.     

Postural Asymmetries in Response to Holding Evenly and Unevenly Distributed Loads During Self-Selected Stance

The authors examined postural asymmetries during quiet stance and while holding evenly or unevenly distributed loads. Right-hand dominant subjects preferentially loaded their right lower limb when holding no load or a load evenly distributed in both hands, but no differences in center of pressure (CoP) were observed between the left and right limbs. However, longer CoP displacement was observed under the preferentially loaded limb, which may reflect a functional asymmetry that allows quick movement of one limb in response to a potential perturbation. When a load was held only in the nondominant hand, sample entropy decreased in the left (loaded) limb but increased in the right (unloaded) limb, suggesting the unloaded foot compensated for a loss of control flexibility in the loaded foot.     

Learning and extrapolating a periodic function

How people learn continuous functional relationships remains a poorly understood capacity. In this article, I argue that the mere presence of nonmonotonic extrapolation of periodic functions neither threatens existing theories of function learning nor distinguishes between them. However, I show that merely learning periodic functions is extremely difficult. It is only when stimuli are presented numerically, rather than as numberless quantities, that participants learn anything like a periodic function. In addition, I show that even then, people do not regularly extrapolate periodically. The lesson is that careful methodologies will be required to understand a psychological capacity that is as idiosyncratic as the learning of complex functions appears to be.     

State-trace analysis can be an appropriate tool for assessing the number of cognitive systems: A reply to Ashby (2014)

Ashby (2014) has argued that state-trace analysis (STA) is not an appropriate tool for assessing the number of cognitive systems, because it fails in its primary goal of distinguishing single-parameter and multiple-parameter models. We show that this is based on a misunderstanding of the logic of STA, which depends solely on nearly universal assumptions about psychological measurement and clearly supersedes inferences based on functional dissociation and the analysis of interactions in analyses of variance. We demonstrate that STA can be used to draw inferences concerning the number of latent variables mediating the effects of a set of independent variables on a set of dependent variables. We suggest that STA is an appropriate tool to use when making arguments about the number of cognitive systems that must be posited to explain behavior. However, no statistical or inferential procedure is able to provide definitive answers to questions about the number of cognitive systems, simply because the concept of a “system” is not defined in an appropriate way.     

Leave Her out of It: Person‐Presentation of Strategies is Harmful for Transfer

A common practice in textbooks is to introduce concepts or strategies in association with specific people. This practice aligns with research suggesting that using “real‐world” contexts in textbooks increases students’ motivation and engagement. However, other research suggests this practice may interfere with transfer by distracting students or leading them to tie new knowledge too closely to the original learning context. The current study investigates the effects on learning and transfer of connecting mathematics strategies to specific people. A total of 180 college students were presented with an example of a problem‐solving strategy that was either linked with a specific person (e.g., “Juan's strategy”) or presented without a person. Students who saw the example without a person were more likely to correctly transfer the novel strategy to new problems than students who saw the example presented with a person. These findings are the first evidence that using people to present new strategies is harmful for learning and transfer.     

Essentialist to some degree: beliefs about the structure of natural kind categories

Previous research has provided conflicting evidence regarding the hypothesis that people are essentialists. Much of the evidence in favor of essentialism is based on demonstrating that categories are thought to have absolute membership. Although the hypothesis is often framed as an absolute claim about all categories of a certain type (e.g., natural kinds), it has generally been tested by making relative comparisons with a select sample. The present study assesses judgments of absolute structure across a range of categories. A further condition for essentialism is that the criteria for category identity be seen as objective rather than conventional. The results of three experiments based on these considerations do not provide support for essentialist claims. Few categories were judged to have essentialist structure, in terms of either absolute membership or objective criteria. Results are discussed in light of an alternative to the essentialist hypothesis that emphasizes a pragmatic view of categories.     

The role of attention shifts in the categorization of continuous dimensioned stimuli

Results of human category learning experiments, using stimulus dimensions with binary values, have implicated a rapidly acting mechanism of attention shifts. Theories of categorization desire that stimuli with binary, discrete and continuous valued dimensions should all be treated similarly. Theoretical analyses of attention shifting, however, have up to now only been developed for shifts between features, or shifts between entire dimensions, not shifts within dimensions. Here we present a model of how people learn to discriminate categories made up of stimuli with continuous-valued dimensions. The model uses rapid shifts in attention within stimulus dimensions to reduce errors during learning; the model generalizes J. K. Kruschke's (Psychological Review, 99, 22–44, 1992) ADIT model. In an experiment in category learning, subjects were trained to discriminate four bivariate normal distributions that are presented with differential base rates. The base-rate manipulation produces several qualitative effects, for which the model accounts very well. With attention shifting turned off, the model fails to account for some aspects of the data, suggesting that attentions shifts are an important mechanism in the model. Received: 20 November 1998 / Accepted: 25 August 1999