What do visual neurons compute? A recent review [1] states that current models of the primary visual cortex (V1) of mammals explain less than 50% of neuron response variance and that “as much as 85% of V1 function has yet to be accounted for”. In this essay, we shall consider some of the essential facts of natural vision and argue that the organization of behaviour plays a crucial role in shaping the design of visual neurons. We conclude that the specific movements and perspectives of animals need to be taken into account when using natural images or image sequences in the analysis of visual processing in neurons.