There is substantial evidence that object representations in adults are dynamically adapted by learning. Here we show that these effects are induced by active processing of objects in a particular task context, and not merely by visual exposure to objects during training. We derived behavioural sensitivity and neural selectivity for shape differences in a psychophysical and an event-related fMRI-adaptation study, respectively. We had two training conditions: “categorised objects” were categorised at a subordinate level based on fine shape differences, while “control objects” were seen equally often in a task context requiring no subordinate categorisation. After training,categorised objects were more easily discriminable than control objects and object-selective cortex was more selective for differences among categorised than control objects. These results indicate that the task context modulates the extent to which shape similarity is altered as a result of training, both at the behavioural and at the neural level.