Abstract Monkeys were trained to respond to left or right according to the colour of a brief central light. They were tested for retention of this discrimination task following bilateral lesions of either the frontal eye-field, dorsolateral frontal cortex, or the superior colliculus. Impairment was found after frontal eye-field lesions only. Subsequently tests were given in which an irrelevant white light was flashed peripherally at the start of a trial. These indicated a reduced distractibility following both collicular lesions and frontal eye-field lesions, though in the latter case this look the form only of a reduction in the duration of distraction, rather than a reduction in its probability of occurrence.