In tool use, a transformation rule defines the relation between an operating movement and its distal effect. This rule is determined by the tool structure and requires no explicit definition. The present study investigates how humans represent and apply compatible and incompatible transformation rules in tool use. In Experiment 1, participants had…

Language production has been found to be lateralized in the left hemisphere (LH) for 95% of right-handed people and about 75% of left-handers. The prevalence of atypical right hemispheric (RH) or bilateral lateralization for reading and colateralization of production with word reading laterality has never been tested in a large sample. In this…

Theory suggests that the vision-for-perception and vision-for-action processing streams operate under very different temporal constraints (Glover, 2004; Goodale, Jackobson, & Keillor, 1994; Graham, Bradshaw, & Davis, 1998; Hu, Eagleson, & Goodale, 1999). With the present study, children and young adults were asked to estimate how far a cued target…

Simultaneously executed limb movements interfere with each other. Whereas the interference between discrete movements is examined mostly from a cognitive perspective, that between rhythmic movements is studied mainly from a dynamical systems perspective. As the tools and concepts developed by both communities are limited in their applicability to…

In this special section, 6 articles address the provocative question of how to determine the boundary between difference and deficiency, for children who differ from the mainstream in some way--language, hearing, cultural background, socioeconomic status, or social understanding. Our commentary considers these articles in light of current models…

It has been proposed that switch costs in task switching reflect the strengthening of task-related associations and that strengthening is triggered by response execution. The present study tested the hypothesis that only task-related responses are able to trigger strengthening. Effects of task strengthening caused by error corrections were…

Rationale: Functional transcranial Doppler sonography (fTCD) during word generation is well established for language lateralization. In this study, we evaluated a fTCD paradigm to reliably identify the non-dominant hemisphere. Methods: Twenty-nine right-handed healthy subjects (27.1 [plus or minus] 7.6 years) performed the "cube perspective test"…

Purpose: This study investigated the network of brain regions involved in overt production of vowels, monosyllables, and bisyllables to test hypotheses derived from the Directions Into Velocities of Articulators (DIVA) model of speech production (Guenther, Ghosh, & Tourville, 2006). The DIVA model predicts left lateralized activity in inferior…

The authors used a modified Simon task (J. R. Simon, 1969) to assess the automatic recognition of handedness. Participants responded to the color of a circle in the center of the photograph of a right or a left hand, displayed in the center of the computer screen. A regular Simon effect was found for back views, whereas a reverse Simon effect was…

Identifies three main strengths of Casey's spatial ability model, but notes that a study by McKeever found different results concerning the relationship between familial handedness and females' mental rotation ability. Considers the use of a familial handedness measure to be a weakness of the model because handedness might not be an inherited…

Evaluated 9-, 14-, and 19-month olds' strategies as they grasped and used spoons presented with the handle alternately oriented to left or right. Found that younger children reached with their preferred hand, disregarding the item's orientation. Older children anticipated the problem, alternated the hand used, and achieved an efficient radial grip…

Notes Halpern's general support for Casey's model. Addresses differences in Casey's and McKeever's findings on familial handedness and females' spatial ability by performing another experiment in which data are analyzed according to two different theoretical assumptions. Addresses the question of the heritability of handedness by noting that what…

Examined ability of individuals biologically predisposed to poor spatial skills to capitalize on opportunities to develop these skills. Found that for girls with brothers, those from all right-handed families had lower mental-rotation scores than did others. Among children participating in mental-rotation-type activities with their brothers,…