When do you look where you look? A visual field asymmetry

•Pre-saccadic fixation durations were longer for downward than upward saccades.•The asymmetry reflects factors not directly related to fixated elements.•Saccades were more likely to be directed upwards than downwards.•Directional constraints are important in modelling when the eyes move.

Pre-saccadic fixation durations associated with saccades directed in different directions were compared in three endogenous-attention oriented saccadic scanning tasks (i.e. visual search and scene viewing). Pre-saccadic fixation durations were consistently briefer before the execution of upward saccades, than downward saccades. Saccades also had a higher probability of being directed upwards than downwards. Pre-saccadic fixation durations were symmetric and longer for horizontally-directed saccades. The vertical visual field asymmetry in pre-saccadic fixation durations reflects an influence of factors not directly related to currently fixated elements. The ability to predict pre-saccadic fixation durations is important for computational modelling of real-time saccadic scanning, and the findings make a case for including directional constraints in computational modelling of when the eyes move.