REACTION-TIME IMPROVEMENTS WITH PRACTICE IN BRAIN-DAMAGED PATIENTS

This study investigated practice effects on reaction time (RT) in pati ents with unilateral brain damage and age-matched controls. Subjects p erformed a Sternberg-type stimulus recognition task. Both RT and RT va riability decreased in all subjects from a short initial session, to a second session, 1 to 3 days later. Within the second session, however , RT remained constant in the controls, whereas it was further reduced in the patients. These findings argue against the assumption that bra in-damaged patients generally show smaller practice effects on RT than controls, and instead suggest that it may be essential to provide pat ients with sufficient practice opportunities. To locate the processing stage where practice is effective, analyses were performed also on th e intercept and slope parameters of the RT function. It is argued that .the differential practice effects were due to the speeding of percept ual and/or response-related stages, rather than gains in memory search speed.