Directional bias in the mental representation of spatial events: nature or culture?

Previous research has shown a tendency for people to imagine simple sentences as evolving from left to right, with the sentence subject being located to the left of the object. In two cross-cultural studies comparing Italian and Arab participants, we investigated whether this bias is a function of hemispheric specialization or of directionality of written language (left to right in Italian, right to left in Arabic). Both studies found a reversal of directional bias in Arabs. Italians tended to position the subject to the left of the object, and Arabs tended to position the subject to the right of the object (Experiment 1); both groups were facilitated in a sentence-picture matching task when the subject was drawn in the position that it would usually occupy in the written language (left for Italians, right for Arabs; Experiment 2). In Experiment 2, an additional, language-independent facilitation was observed when action evolved from left to right, suggesting that both hemispheric specialization and scanning habit affect visual imaging.     

Word identification in adults with mild mental retardation: does IQ influence reading achievement?

OBJECTIVE: To assess the relationship between word identification and intelligence in adults with mild mental retardation (IQ < 80). METHOD: A standardized evaluation was administered to 67 adults with mild mental retardation. The evaluation included a psychiatric interview, the WAIS-R, and a 2-h interview with a speech therapist and reading tests. RESULTS: Causes of mental retardation were diverse in the sample, and IQ scores ranged from 43 to 79 (mean score = 64). All subjects exhibited reading impairment, including 69% with severe impairment. No subject with an IQ score under 65 was able to perform adequately in the word identification tasks. Word identification was correlated with total and verbal IQ, but not with performance IQ. CONCLUSION: Our results suggest that, in contrast to subjects with normal intelligence, IQ score is correlated with reading in subjects with mild mental retardation. Finally, remediation should be preferentially implemented for subjects with IQ score greater than 65.     

Functional plasticity of sensorimotor representations following short-term immobilization of the dominant versus non-dominant hands

The main purpose of the present study was to investigate the functional plasticity of sensorimotor representations for dominant versus non-dominant hands following short-term upper-limb sensorimotor deprivation. All participants were right-handed. A splint was placed either on the right hand or on the left hand of the participants during a brief period of 48 h and was used for the input/output signal restrictions. The participants were divided into 3 groups: right hand immobilization, left hand immobilization and control (without immobilization). The immobilized participants performed the hand laterality task before (pre-test) and immediately after (post-test) splint removal. The pre-/post-test procedure was similar for the control group. The main results showed a significant response time improvement when judging the laterality of hand stimuli in the control group. In contrast, the results showed a weaker response time improvement for the left-hand immobilization group and no significant improvement for the right-hand immobilization group. Overall, these results revealed that immobilization-induced effects were lower for the non-dominant hand and also suggested that 48 h of upper-limb immobilization led to an inter-limb transfer phenomenon regardless of the immobilized hand. The immobilization-induced effects were highlighted by the slowdown of the sensorimotor processes related to manual actions, probably due to an alteration in a general cognitive representation of hand movements.