It can make a fan’s blood boil: Two players lunge for a soccer ball, one of them kicks it out of bounds, and now both are claiming the other touched it last. We may rightly chalk up many “last touch” disagreements to players’ wishful thinking, or to outright deception. But psychologists have identified another possible factor at play—a natural tendency to think our own actions come before external events.
To look for this tendency in the lab, the researchers had pairs of people sit across from each other and asked them both to tap their partner’s left hand with their right finger as soon as they saw a light flash. Sensors on the backs of their left hands revealed who tapped first. After each trial, participants were asked to render their own judgment.
A clear bias emerged: In cases where the taps were simultaneous, participants had a 67% chance of claiming the first touch, researchers report today in Science Advances. And on average, they judged the taps to be simultaneous even when their own tap was about 50 milliseconds behind their partner’s. These results held up when the participants no longer had a human opponent and simply compared their response time with a tap from a mechanical device or a clicking sound.
The finding fits with previous results suggesting we judge events to happen earlier if we think we caused them. The authors suggest the effect may trace to a part of the brain called the supplementary motor cortex, which has been shown to have distinct patterns of activity during self-initiated events versus externally triggered ones. The study helps pin down one way that our vantage point shapes perception, but don’t expect that to placate angry soccer fans.