Processes of similarity judgment

Similarity underlies fundamental cognitive capabilities such as memory, categorization, decision making, problem solving, and reasoning. Although recent approaches to similarity appreciate the structure of mental representations, they differ in the processes posited to operate over these representations. We present an experiment that differentiates among extant structural accounts of similarity in their ability to account for patterns of similarity ratings. These data pose a challenge for transformation-based models and all but one mapping-based model, the Similarity as Interactive Activation and Mapping (SIAM) model of similarity.     

Perception as abduction: turning sensor data into meaningful representation

This article presents a formal theory of robot perception as a form of abduction. The theory pins down the process whereby low-level sensor data is transformed into a symbolic representation of the external world, drawing together aspects such as incompleteness, top-down information flow, active perception, attention, and sensor fusion in a unifying framework. In addition, a number of themes are identified that are common to both the engineer concerned with developing a rigorous theory of perception, such as the one on offer here, and the philosopher of mind who is exercised by questions relating to mental representation and intentionality.     

Expectations about numerical events in four lemur species (Eulemur fulvus, Eulemur mongoz, Lemur catta and Varecia rubra)

Although much is known about how some primates—in particular, monkeys and apes—represent and enumerate different numbers of objects, very little is known about the numerical abilities of prosimian primates. Here, we explore how four lemur species (Eulemur fulvus, E. mongoz, Lemur catta, and Varecia rubra) represent small numbers of objects. Specifically, we presented lemurs with three expectancy violation looking time experiments aimed at exploring their expectations about a simple 1+1 addition event. In these experiments, we presented subjects with displays in which two lemons were sequentially added behind an occluder and then measured subjects duration of looking to expected and unexpected outcomes. In experiment 1, subjects looked reliably longer at an unexpected outcome of only one object than at an expected outcome of two objects. Similarly, subjects in experiment 2 looked reliably longer at an unexpected outcome of three objects than at an expected outcome of two objects. In experiment 3, subjects looked reliably longer at an unexpected outcome of one object twice the size of the original than at an expected outcome of two objects of the original size. These results suggest that some prosimian primates understand the outcome of simple arithmetic operations. These results are discussed in light of similar findings in human infants and other adult primates.This revised version was published online in March 2005 with corrections to Fig. 6.     

Individual differences in susceptibility to experimentally induced phantom sensations

We investigated individual differences in susceptibility to two vibration-induced phantom illusions, i.e. illusory arm extension and nose prolongation (“Pinocchio illusion”). Vibration was applied to the biceps brachii tendon of 32 healthy participants. Susceptibility to the illusions was quantified by vividness ratings and by ratings of the amount of illusory position changes of the arm and illusory shape changes of the nose. Participants also completed the Perceptual Aberration (PA) and the Need for Cognition (NFC) inventories. PA reflects the frequency of spontaneously experienced body schema alterations and NFC a person's tendency to cognitively structure experiences. PA was positively correlated with participants’ susceptibility to illusory arm extension and, exclusively for men, also to nose elongation. A high NFC was weakly associated with a high susceptibility for the Pinocchio illusion. By inference, these findings indicate a physiological basis of PA and a cognitive mediation of experimentally induced phantom sensations.     

Partial Knowledge of Word Meanings: Thematic and Taxonomic Representations

The type of information (taxonomic or thematic) available at different levels of knowledge was investigated. Following extensive norming to identify taxonomic and thematic associates of low-frequency nouns, participants determined if taxonomic or thematic associates were meaningfully related to target words at three levels of knowledge: target words they correctly defined (known), recognized as familiar (frontier), or mistakenly denied as part of the language (unknown). In another experiment, participants reported which type of relationship (taxonomic or thematic) was preferred. Results indicated that both types of information were available at all levels of knowledge. However, accuracy and preference were greater for taxonomic associates across word levels. A differential increase in available thematic information relative to taxonomic information was found. Implications for the acquisition and representation of word meanings are discussed.     

小学2～4年级儿童数学应用题表征策略差异的研究

本研究运用实验法和临床访谈法对某普通小学的123名2～4年级学生进行了数学应用题测验,以考察数学学优生和学差生在解决比较应用题时表征策略的差异。结果表明:(1)从2～4年级儿童解答一致和不一致应用题上看,学优生较多地使用问题模型策略对问题进行表征,学差生较多地使用直接转换策略对问题进行表征;(2)除学差女生的解题正确率低于学差男生的正确率,学差女生自我报告中直接转换策略的使用多于学差男生外,在其它方面,性别差异并不显著;(3)随着年级的升高,学优生在使用问题模型策略上越来越成熟,学差生并没有学会使用更加有效的问题模型表征策略,仍然停留在直接转换策略上,但他们在关于策略使用的认识上有所提高。     

On the representation of Portuguese gender-inflected words in the mental lexicon

This study aims at verifying whether Portuguese gender-inflected nouns and adjectives are represented as full forms as suggested by Spanish data (Dominguez, Cuetos, & Segui, 1999). A series of lexical decision experiments is reported. Grammatical gender, frequency dominance, and grammatical category are manipulated and cumulative frequency is controlled. The results do not provide support for a full form representation of gender-inflected words. They suggest that grammatical category, or the nature of the inflectional process involved (lexical or syntactic), affects the way words are represented and accessed. Shorter recognition latencies were obtained for nouns drawn from Feminine dominant gender-inflected pairs than from Masculine dominant pairs whereas a tendency in the opposite direction was observed in adjectives. The effect of frequency dominance appears, nevertheless, to be restricted to feminine nouns. The data are compatible with the view that masculine nouns and adjectives are represented as gender-unmarked forms. These results are discussed in relation to current dual-access models of word recognition and to the notion of "interpretability" of lexico-syntactic features, as put forward in the Minimalist Program of Generative Linguistics.     

A computational feature binding model of human texture perception

We present a computational model for human texture perception which assigns functional principles to the Gestalt laws of similarity and proximity. Motivated by early vision mechanisms, in the first stage, local texture features are extracted by utilizing multi-scale filtering and nonlinear spatial pooling. In the second stage, features are grouped according to the spatial feature binding model of the competitive layer model (CLM; Wersing et al. 2001). The CLM uses cooperative and competitive interactions in a recurrent network, where binding is expressed by the layer-wise coactivation of feature-representing neurons. The Gestalt law of similarity is expressed by a non-Euclidean distance measure in the abstract feature space with proximity being taken into account by a spatial component. To choose the stimulus dimensions which allow the most salient similarity-based texture segmentation, the feature similarity metrics is reduced to the directions of maximum variance. We show that our combined texture feature extraction and binding model performs segmentation in strong conformity with human perception. The examples range from classical microtextures and Brodatz textures to other classical Gestalt stimuli, which offer a new perspective on the role of texture for more abstract similarity grouping.     

Representing others' actions: just like one's own?

Previous research has shown that observing others' actions can affect individual performance of the same actions. In the present study, we developed a new paradigm to investigate whether and how complementary actions at the disposal of another agent are represented and influence one's own actions. A spatial compatibility task was distributed among two people so that each participant took care of one of two responses. The identical task was performed alone and alongside another participant. There was a spatial compatibility effect in the group setting only. It was similar to the effect obtained when one person took care of both responses. This result suggests that one's own actions and others' actions are represented in a functionally equivalent way.