Psychological refractory period
![Figure 1. Model of the central bottleneck accounting for the psychological refractory period. Execution of one task requires three stages: Stage 1 entails the analysis of the perceptual characteristics of the stimulus, Stage 2 entails a decision about what the task-set requires, Stage 3 is the execution of the actual response. Shaded stages cannot overlap, but if they do, for example when the time intervening between the two tasks (SOA) is short, the one that has priority (i.e., the first task) will delay (SLACK) the execution of the second. This phenomenon is known as the psychological refractory period.](/Images/godic/202502/05/BottleneckInterefencePRP.svg0310.png")
The term psychological refractory period (PRP) refers to the period of time during which the response to a second stimulus is significantly slowed because a first stimulus is still being processed. This delay in response time when one is required to divide attention can exhibit a negative effect that is evident in many fields of study. The PRP can be used to investigate many areas of research that study processes which require divided attention, such as reading aloud, language, or driving and talking on the phone. PRP effects related to personality, age, and level of alcohol or caffeine intake have also been investigated.