cerebellar encoding of multiple candidate error cues in the service of motor learning for learning to occur through trial and error the nervous system must effectively detect and encode performance errors to examine this process we designed a set of oculomotor learning tasks with more than one visual object providing potential error cues as would occur in a natural visual scene a taskrelevant visual target and a taskirrelevant visual background both influenced vestibuloocular reflex learning in rhesus monkeys thus motor learning does not identify a single error cue based on behavioral relevance but can be simultaneously influenced by more than one cue moreover the relative weighting of the different cues could vary if the speed of the visual targets motion on the retina was low 1s background motion dominated learning but if target speed was high the effects of the background were suppressed the target and background motion had similar nonlinear effects on the putative neural instructive signals carried by cerebellar climbing fibers but with a stronger influence of the background on the climbing fibers than on learning in contrast putative neural instructive signals carried by the simple spikes of purkinje cells were influenced solely by the motion of the visual target because they are influenced by different cues during training joint control of learning by the climbing fibers and purkinje cells may expand the learning capacity of the cerebellar circuit