Imagine a championship match between two rival basketball teams. The game is tied, seconds left on the shot clock, two players lunge forward, reaching for the ball. In a split second, their hands both collide with the ball, but neither player gains possession. Instead, the ball goes soaring out of bounds. Immediately an argument erupts as each player claims the other knocked the ball out. The referee desperately tries to break the two apart and make the correct call.
Heated arguments like this are an all-too-familiar sight in competitive sports. From tennis to baseball to football (both versions) to basketball, referees and umpires have a tough job: making high-stakes judgment calls on what happened and where, knowing full well that no matter what they decide, players and fans alike will be outraged.
As cognitive scientists, my colleagues and I are interested in explaining differences in perception among people watching the same events unfold. In baseball, researchers already know that differences in the speed of sound versus the speed of light can cause different perceptions of whether a player is safe or out. What about in the basketball example? Are both players simply lying to get the ball back to their team, or is there something more going on?
How time passes is subjective
First, you need to understand a little about time. Time is subjective. Physicists have known this to be true since 1905, thanks to Einstein himself. Most simply, his theory suggested that time passes differently depending on factors like speed and gravity. (Remember the movie “Interstellar”?)
Subjective time, however, is not limited to the fantasies of science fiction and thought experiments in physics. Many researchers, such as neuroscientist David Eagleman, have studied neurological time and how your own experiences can shape your perception of time, such as how time seems to slow down during a traumatic experience.
In 2002, cognitive neuroscientist Patrick Haggard and his colleagues showed that voluntary action has the ability to shape one’s perception of time. In their study and subsequent replications, it was shown that an action and its effect can be perceptually “bound” together in time.
For example, if you use an outdated computer, you may be familiar with the experience of double-clicking a folder, only for it to open several hundred milliseconds later. At first, this delay can be frustrating. But over time, you adapt to the delay and it feels nearly instantaneous.
This process of adapting to the delay, called “intentional binding” by researchers, paved the way for studies investigating how the feeling of ownership over events affects your perception of what happened. With the slow computer, you know that the folder opening was a result of your clicking, even if it happened later. This knowledge and feeling of ownership over the opening of the folder is what results in intentional binding, and leads to the delay feeling shorter as you adapt to it.
Putting time estimates to the test
Going back to those two basketball players (who’ve called a time out to cool off while we figure this out) – objectively, they can’t both have touched before the other. However, we wanted to know whether both players could have really experienced that they touched the ball first and the other person knocked it out.
In order to test this possibility, we devised a simple experiment. Two participants sat across from one another at a table. Following a flash of light, each used their right hand to tap the other’s left hand as quickly as they could. They then made a temporal order judgment – a decision on which event happened first.