Patterns of perceived similarity cannot be generalized from long to short exposure durations and vice versa

Subjects rated the perceived similarity between patterns and their 180-deg rotational variants. The stimuli, adapted from Halpern, Fishbein, and Warm (1979), were randomly generated dot patterns and line drawings and polygons generated from the dot patterns. Inspection time was varied in a between-subject design. As in the Halpern et al. (1979) study, it was found that the variables of form type (dots, lines, polygons) and axis of rotation (x, y, z) had no effect on perceived similarity in the long exposure conditions. However, when inspection time was limited to 150 msec, both variables had a substantial impact. This finding undermines the frequent practice of selecting stimuli for use in reaction time or other experiments with limited inspection time on the basis of similarity ratings gathered under typical free inspection conditions.     

If the boy loves the girl and the girl loves the dog,does the boy love the dog?: The overgeneralization of verbal transitive inference skills

Two studies investigated 4- to 10-year-old children's capacity to make verbal transitive inferences. The results of the two studies suggest that the development of transitive inference skills follows a specific to general developmental path, and that children overgeneralize their verbal transitive inference skills to inappropriate relational terms prior to determining the general principle that underlies the use of relational terms in transitive sentences.     

Latent Class Analysis of Adolescent Psychosocial Functioning and Course of Major Depression

Research on Child and Adolescent Psychopathology - There are few studies on the predictors of long-term course of major depressive disorder (MDD) with an onset in childhood and adolescence. Studies...     

Pooling Modalities and Pointwise Intersection: Axiomatization and Decidability

Studia Logica - We establish completeness and the finite model property for logics featuring the pooling modalities that were introduced in Van De Putte and Klein (Pooling modalities and...     

Effects of naturally-occuring nontraumatic separations from mother

Thirty-three twelve-month-old infants were divided into three groups based on the frequency and length of naturally-occurring nontraumatic separations from mother during the first year. One group had experienced only brief separations when left with a babysitter for an evening. A second group had been left once or twice for an average of five days while parents vacationed. A third group had been left regularly and frequently during the daytime, usually because mother was working. These groups were compared on measures of reaction to separation and reunion, in the home and in the laboratory, at one year of age. No group differences were found on any of the dependent variables. It is suggested that the quality of substitute care is probably more important than separation per se in mediating the impact of employment or daycare on infant development.     

Does spreading activation summate?

Summary Network models of semantic memory assume implicitly or explicitly that the degree of activation of a node is a monotonic function of the total amount of excitation reaching that node from all sources. For example, the activation level of the node representing apple should be greater if it is receiving excitation due to the activation of the nodes for fruit and pear than if only one of these neighboring nodes is activated. This notion was tested by presenting semantic primes 80 ms or 320 ms before a letter string (e.g., apple or ipple) requiring a lexical decision. The prime stimuli consisted of a pair of simultaneous items that were identical in the single prime condition (e.g., fruit/fruit or pear/pear) or different in the double prime condition (e.g., fruit/pear or pear/fruit), and were either related (target = apple) or unrelated (target = copper) to the target, or neutral. As predicted by the summation of semantic activation assumption of network models there was a larger priming effect (in the 320 ms SOA condition) following the simultaneous activation of two related nodes than following the activation of only one node.This research was supported by grants to the first author from the Natural Sciences and Engineering Research Council of Canada.