Configural biases and reversible figures: evidence of multilevel grouping effects

Four experiments sought to identify the processes underlying 2 classes of grouping effects that are readily produced with a hierarchical figure type known as ambiguous triangles. Previous work has shown that aligning small equilateral triangles in particular configurations can both facilitate and interfere with observers' ability to report the pointing direction of the individual triangles. We determined that selectively adapting the observer to low-frequency gratings of the same orientation as the aligned triangles markedly altered the interfering and facilitative effects of the global configuration only when an accuracy measure of performance was used. When a response latency measure was used, no effect of the same adaptation condition was found. Results are discussed in terms of multiple levels of grouping effects in the visual system and the differential sensitivity of these levels to basic neural adaptation.     

Processing speed in the 1st year of life: a longitudinal study of preterm and full-term infants

Processing speed was assessed at 5, 7, and 12 months in full-term and preterm infants (birth-weight < 1,750 g). Speed was gauged directly in a new task by presenting infants with a series of paired faces, one that remained the same across trials and one that changed; trials continued until infants showed a consistent novelty preference. At all ages, preterms required about 20% more trials and 30% more time than full-terms to reach criterion. Among preterms, slower processing was associated with greater medical risk (e.g., respiratory distress syndrome). Developmental trajectories for speed (and attention) were similar for both groups. Thus, the deficits in processing speed previously found for preterms in childhood are already present in the 1st year of life.     

Leaders' anticipated and targets' self-reported resistance to task assignments: a replication

This is a follow up study of Barbuto's 2000 work in which leaders' ratings and targets' self-reported resistance to task assignments are compared. Scores on the Anticipated Resistance Indicator among 650 leader-member dyads measure resistance based on Barbuto's 1997 five concentric zones of Preference, Indifference, Legitimate, Influence, and Noninfluence, examined from both leaders' and targets' perspectives. Responses indicated that leaders tend to underestimate followers' willingness to perform assigned tasks. In addition, leaders tend to overestimate targets' unwillingness to perform undesirable, less enjoyable tasks.     

Multiple cues for quantification in infancy: is number one of them?

A review and synthesis of the literature on quantification in infancy and early childhood is provided. In most current conceptualizations, early quantification is assumed to be number based. However, the extant literature provides no clear-cut evidence that infants use number to perform quantitative tasks. Instead, new research suggests that quantification is initially based on nonnumerical cues, such as area and contour length, whether or not a task involves discrete items. The authors discuss the implications of these findings with respect to early quantification and its relation to later numerical development.     

Content mazes and filled pauses in narrative language samples of children with specific language impairment

Linguistic nonfluencies known as mazes (filled pauses, repetitions, revisions, and abandoned utterances) have been used to draw inferences about processing difficulties associated with the production of language. In children with normal language development (NL), maze frequency in general increases with linguistic complexity, being greater in narrative than conversational contexts and in longer utterances. The same tendency has been found for children with specific language impairment (SLI). However, the frequency of mazes produced by children with NL and SLI has not been compared directly at equivalent utterance lengths in narration. This study compared the frequency of filled pauses and content mazes in narrative language samples of school-age children with SLI. The children with SLI used significantly more content mazes than the children with NL, but fewer filled pauses. Unlike content mazes, the frequency of filled pauses remained stable across samples of different utterance lengths among children with SLI. This indicates that filled pauses and content mazes have different origins and should not be analyzed or interpreted in the same way.