The psychological refractory period (PRP) is the delay in responding to a second stimulus when it follows shortly after a first stimulus. In sport, an athlete can exploit this delay: a fake triggers an opponent's first response before the athlete performs the intended movement.
Why Does the PRP Occur?
The single-channel hypothesis explains the PRP. Because information-processing capacity is limited, the brain cannot fully select and program two separate responses simultaneously through the same channel.
When two stimuli occur rapidly, the performer processes the first through stimulus identification, response selection, and response programming. The second stimulus may be detected, but selecting and programming its response must wait until first-stimulus processing is completed.
| Stage | Effect during a fake move |
|---|---|
| First stimulus | Defender interprets the fake and starts a response. |
| Second stimulus | Attacker makes the real movement in another direction. |
| PRP delay | Defender cannot immediately select and organize a new response. |
| Outcome | Attacker gains time and space to pass, shoot, or evade. |
For example, a football player shapes their body as if moving left. The defender shifts left, but the attacker then moves right. Because the real movement closely follows the fake, processing the defender's new response is delayed, creating an advantage.
The effect is most useful when the stimuli are separated by a short interval. If it is too long, the defender can reorganize in time.
A common misconception is that PRP simply means slow reaction time. It is the additional delay caused by processing two closely spaced stimuli, not the performer's general response speed.
Exam Technique
For an IB SEHS question on C.2.1 Motor learning processes, define the PRP, explain the single-channel hypothesis, and apply it to a specific example. Identify the fake as the first stimulus and the real action as the second; this explicit sequence demonstrates application.
