Abstract One benefit for prey species living in groups is that predators find it harder to track and target individuals as aggregation size (or density) increases. While this ‘confusion effect’ is known to increase with factors such as object similarity and motion unpredictability, occlusion has received little empirical attention. This is despite the likelihood of a predator’s view of a target being obstructed by other group members moving in three-dimensional space. Using humans as surrogate p