Baseline behaviour in human vision

Humans perceive their visual environment by directing their eyes towards relevant objects. The deployment of visual attention depends substantially on the stimulus's properties, higher cognitive processes, and biases and constraints of the visual system. Numerous models describe people's eye movements depending on the performed task or the viewed content. However, there is no universal, context-invariant model of human gaze behaviour. Here we show that statistical regularities can be utilised to model human gaze behaviour regardless of task, observer, and content. Using a context-agnostic eye movement model, we were able to describe human gaze behaviour better than a uniform random model in various viewing situations. Using a fixed transition kernel, the model can describe gaze patterns during reading, visual search, and scene perception, as well as for both adults and children. Thus, contrary to current belief, human gaze patterns follow a baseline behaviour, making them comparable across contexts. Since gaze behaviour is directly related to brain structure, our results provide the first evidence for the existence of an underlying, context-invariant motor prior in the human visual system.