Mental rotation abilities in individuals with Down syndrome--a pilot study.

This pilot study was designed to examine mental rotation ability in individuals with Down syndrome. 7 individuals with Down syndrome (mean mental age = 8.18 +/- 2.73 years; mean chronological age = 29.8 +/- 5.4 years) and a group of 9 typically developing children, matched for mental age, (mean mental age = 8.40 +/- 1.73 years; mean chronological age = 7.2 +/- 1.2 years) were given a version of Cooper and Shepherd's (1973) mental rotation paradigm. On each trial, participants viewed a symbol representing an upper case 'F' or a mirror image of an 'F'. The symbol was presented at one of eight different orientations. The participant's task was to determine whether the letter was reversed or non-reversed. Interestingly, both groups showed similar trends in increased reaction times with increasing angular disparity, suggesting that both groups were performing mental rotations. There was no significant difference in reaction time between the typically developing and Down syndrome groups, however, the Down syndrome group made significantly more errors than the typically developing group. Participants with Down syndrome were able to carry out the mental rotations at well above chance level and mental rotation ability was shown to correlate with mental age.