Filling the gap despite full attention: the role of fast backward inferences for event completion

The comprehension of dynamic naturalistic events poses at least two challenges to the cognitive system: filtering relevant information with attention and dealing with information that was missing or missed. With four experiments, we studied the completion of missing information despite full attention. Participants watched short soccer video clips and we informed participants that we removed a critical moment of ball contact in half of the clips. We asked participants to detect whether these moments of ball contact were present or absent. In Experiment 1, participants gave their detection responses either directly during an event or delayed after an event. Although participants directed their full attention toward the critical contact moment, they were more likely to indicate seeing the missing ball contact if it was followed by a causally matching scene than if it was followed by an unrelated scene, both for the immediate and delayed responses. Thus, event completion occurs quickly. In Experiment 2, only a causally matching scene but neither a white mask nor an irrelevant scene caused the completion of missing information. This indicates that the completion of missing information is caused by backward inferences rather than predictive perception. In Experiment 3, we showed that event completion occurs directly during a trial and does not depend on expectations built up after seeing the same causality condition multiple times. In Experiment 4, we linked our findings to event cognition by asking participants to perform a natural segmentation task. We conclude that observers complete missing information during coherent events based on a fast backward inference mechanism even when directing their attention toward the missing information.

Seeing the unseen? Illusory causal filling in FIFA referees, players, and novices

Humans often falsely report having seen a causal link between two dynamic scenes if the second scene depicts a valid logical consequence of the initial scene. As an example, a video clip shows someone kicking a ball including the ball flying. Even if the video clip omitted the moment of contact (i.e., the causal link), participants falsely report having seen this moment. In the current study, we explored the interplay of cognitive-perceptual expertise and event perception by measuring the false-alarm rates of three groups with differing interests in football (soccer in North America) (novices, players, and FIFA referees). We used the event-completion paradigm with video footage of a real football match, presenting either complete clips or incomplete clips (i.e., with the contact moment omitted). Either a causally linked scene or an incoherent scene followed a cut in the incomplete videos. Causally linked scenes induced false recognitions in all three groups: although the ball contact moment was not presented, participants indicated that they had seen the contact as frequently when it was absent as in the complete condition. In a second experiment, we asked the novices to detect the ball contact moment when it was either visible or not and when it was either followed by a causally or non-causally linked scene. Here, instead of presenting pictures of the clip, the participants were give a two-alternative forced-choice task: “Yes, contact was visible”, or “No, contact was not visible”. The results of Experiment 1 indicate that conceptual interpretations of simple events are independent of expertise: there were no top-down effects on perception. Participants in Experiment 2 detected the ball contact moment significantly more often correctly in the non-causal than in the causal conditions, indicating that the effect observed in Experiment 1 was not due to a possibly influential design (e.g., inducing a false memory for the presented pictures). The theoretical as well as the practical implications are discussed.