Dual adaptation and adaptive generalization of the human vestibulo-ocular reflex

In two experiments, we examined the possibility that the human vestibule-oc ular reflex (VOR) is subject to dual adaptation (the ability to adapt to a sensory rearrangement more rapidly and/or more completely after repeated ex perience with it) and adaptive generalization (the ability to adapt more re adily to a novel sensory rearrangement as a result of prior dual adaptation training). In Experiment 1, the subjects actively turned the head during a lternating exposure to a visual-vestibular rearrangement (target/head gain = 0.5) and the normal situation (target/head gain = 0.0). These conditions produced both adaptation and dual adaptation of the VOR but no evidence of adaptive generalization when tested with a target/head gain of 1.0. Experim ent 2, in which exposure to the 0.5 gain entailed externally controlled (i. e., passive) whole body rotation, resulted in VOR adaptation but no dual ad aptation. As in Experiment 1, no evidence of adaptive generalization was fo und.