Priming and statistical learning in right brain damaged patients.

We investigated how right hemisphere lesions affected location priming and statistical learning in four groups of participants: young controls, older controls, and right brain damaged patients with or without spatial neglect. Using a version of the Maljkovic and Nakayama's (1994) priming task, but with all the targets presented at the mid-line, we biased the transition probability for targets to repeat their spatial location. The decrease in response time with spatial repetition allowed us to quantify priming, and the modulation of priming strength as a function of repeat probability allowed us to assess for statistical learning. Contrary to the healthy controls, right brain damage decreased (but did not abolish) spatial priming. Right brain damaged patients did not modulate the magnitude of the spatial priming effect with variation in repeat frequency, as did the control groups. We conclude that damage to the right hemisphere impairs spatial priming and that priming impairment co-exists with, and may contribute to an inability to learn environmental statistical regularities. Such deficits could contribute to functional deficits and a poorer response to rehabilitation.