Visual search for features and conjunctions in development.

Visual search performance was examined in 24 7–8 yr olds, 22 9–10 yr olds, 15 11–12 yr olds, and in 10 young adults (aged 23–30 yrs). Color and orientation feature searches and a conjunction search were conducted. Reaction time (RT) showed expected improvements in processing speed with age. Comparisons of RTs on target-present and target-absent trials were consistent with parallel search on the 2 feature conditions and with serial search in the conjunction condition. The RT results indicate that searches for feature arid conjunctions were treated similarly for children and adults. However, the youngest children missed more targets at the largest array sizes, most strikingly in conjunction search. Based on an analysis of speed/accuracy trade-offs, we suggest that low target-distractor discriminability leads to an undersampling of array elements, and is responsible for the high number of misses in the youngest children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing deficits in Turner's syndrome.

Exp I compared 31 female 11–28 yr old Turner syndrome (TS) Ss and 31 matched controls on a mental rotation task. Although both groups utilized the some rotation strategy, TS Ss were less accurate and slower than controls in the rotational component of the task. Exp II compared 23 TS Ss and 23 matched controls (mean age 15.4 yrs) on a sentence verification task. No differences were observed between the groups in accuracy, strategy, or processing rates, although RTs of the TS group were significantly longer. Exp III studied a set of 12.5-yr-old dizygotic twins, one of whom had TS. Results replicate the findings of Exps I and II. Also discussed are the specific processing deficits in TS and the role of biological factors that may contribute to them. (67 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)