Impaired recognition of traffic signs in adults with dyslexia.

Ten adults with dyslexia (4 women and 6 men, mean age: 26.8 years, range: 19-43 years) and 11 controls (5 women and 6 men, mean age: 20.5 years, range: 18-29 years) were tested on their ability to differentiate between real and false traffic signs. The stimuli, computer-presented color pictures, were chosen to minimize the applicability of verbal or written linguistic skills to the task. The adults with dyslexia recognized the traffic signs significantly less well than did the controls. Furthermore, whereas for the controls there was a significant correlation between traffic sign recognition and driving experience, no such correlation was found for the adults with dyslexia. The results are interpreted in terms of a deficit in implicit learning.