Compared the behavior of 10 septal- and 10 hippocampal-lesioned rats with 10 operated controls on 3 tasks requiring different amounts of response inhibition. Rats with septal lesions were impaired on all tasks, displaying a general inability to suppress preferred responses. Hippocampal lesions impaired performance only on a task which contained a formal training period and a shift in experimental conditions. It was concluded that reduced response inhibition is not an invariable consequence of hippocampal damage but occurs in interaction with certain situational factors. Performance of rats with septal lesions was consistent with a simple response-inhibition hypothesis. (PsycINFO Database Record (c) 2006 APA, all rights reserved)