Biomedical subjects

Stella F Lourenco

Publications and source records attributed to Stella F Lourenco.

6 recordsLinked to original sources

PubMed2006

Spatial attention and the mental number line: evidence for characteristic biases and compression.

Numbers are often proposed to be represented spatially as lying along a mental number line. The present study examined whether the direction of spatial attention operates similarly in physical and numerical space. Participants bisected physical lines by indicating the perceived center and "bisected" the mental number line by estimating (without calculating) the number midway between two others. Healthy participants generally show a slight leftward bias (pseudoneglect) when bisecting physical lines. In the present study, pseudoneglect was also observed on mental number line bisection and, importantly, was greater for participants who showed stronger pseudoneglect on physical line bisection. This finding suggests that hemispheric asymmetries in spatial attention operate similarly in physical and numerical space. Furthermore, this bias increased with the average of the numbers, consistent with the proposal that the spatial representation of the mental number line is nonlinearly compressive, with pairs of numbers lying closer together as their magnitude increases.

Adolescent↗

PubMed2006

Using geometry to specify location: implications for spatial coding in children and nonhuman animals.

The study of spatial cognition has benefited greatly from a technique known as the disorientation procedure. This procedure was originally used with rats to show that they relied on the geometry of an enclosed space to locate a target hidden in that space. Disorientation has since been used with a variety of mobile animals, including human children, to examine the coding of geometric information. Here, we focus mostly on our recent work with young children. We examine a set of issues concerning reorientation--namely, the nature of geometric coding, the processes invoked by disorientation, and the developmental origins of using geometric information to determine location. We have employed a variety of methods to examine these issues; the methods include analyzing search behaviors, using spaces of different shapes, varying viewing position, and comparing different disorientation procedures. The implications for how children and nonhuman animals code geometric information are discussed.

Animals↗

PubMed2005

On the nature of near space: effects of tool use and the transition to far space.

Many researchers have proposed that the near space immediately surrounding the body is represented differently than more distant space. Indeed, it has often been suggested that near space encompasses that within arm's reach. The present study used a line bisection task in healthy adults to investigate the effects of tool use on space perception, and the nature of the transition between near and far space. Subjects bisected lines at four distances controlled for both veridical and angular size using a laser pointer and a set of sticks. When the laser pointer was used, a left to right shift in bias was observed as stimuli were moved from near to far space. When a tool was used, however, a leftward bias was observed at all distances, similar to that observed with the laser pointer in near space. These results suggest that the tool expanded the range of near space. Additionally, the transition from near to far space was gradual, with no abrupt shift at arm's length (or at any other distance). In contrast to theories describing near space as that within arm's reach, these findings suggest that the representation of near space is less rigid, extending with tool use and gradually transitioning into far space.

Adolescent↗

PubMed2005

How do young children determine location? Evidence from disorientation tasks.

Previous studies show that following disorientation children use the geometry of an enclosed space to locate an object hidden in one of the corners [e.g. (Hermer, L., & Spelke, E. (1996). Modularity and development: A case of spatial reorientation. Cognition, 61, 195-232)]. These studies have used a disorientation procedure that involves rotating the viewer (with eyes closed). Here, we examine 18- to 25-month-olds' spatial coding in two disorientation tasks--involving either viewer or space rotation. Importantly, the rotational movements in both tasks could not be visually tracked. Children were tested in either task (viewer- or space-movement) from either inside or outside a triangular (isosceles) space (with one unique and two equivalent corners). In the viewer-movement task, performance was above chance, regardless of which corner contained the object. In the space-movement task, performance was above chance at only the unique corner. On both tasks, performance was better from inside the space than from outside. The implications for how children determine location are discussed.

Child, Preschool↗

PubMed2005

Toddlers' representations of space: the role of viewer perspective.

In the present study, we examined how people code object location when an object is hidden in an enclosed space. On object location tasks involving disorientation, viewers must code the location of an object in relation to the spatial environment because they cannot directly track their changing relation to the object. Recently, we showed that viewers also code their perspective relative to the entire space (inside vs. outside) in such tasks. To determine whether viewers code perspective whenever they must locate an object, we examined young children's performance on a task in which coding perspective would be difficult. Our task involved both disorientation and translation (i.e., movement from inside to outside the space or vice versa). When translation preceded disorientation, performance was comparable to performance on tasks with no translation. However, when disorientation preceded translation, performance was at chance. The implications of these findings for location coding are discussed.

Awareness↗

PubMed2005

Socioeconomic status modifies the sex difference in spatial skill.

We examined whether the male spatial advantage varies across children from different socioeconomic (SES) groups. In a longitudinal study, children were administered two spatial tasks requiring mental transformations and a syntax comprehension task in the fall and spring of second and third grades. Boys from middle- and high-SES backgrounds outperformed their female counterparts on both spatial tasks, whereas boys and girls from a low-SES group did not differ in their performance level on these tasks. As expected, no sex differences were found on the verbal comprehension task. Prior studies have generally been based on the assumption that the male spatial advantage reflects ability differences in the population as a whole. Our finding that the advantage is sensitive to variations in SES provides a challenge to this assumption, and has implications for a successful explanation of the sex-related difference in spatial skill.

Adolescent↗