User talk:Sara Frances Garcia/sandbox

The term Psychological refractory period (PRP) refers to the delay observed in the execution of the second of two tasks when it must be in close temporal succession with a prior task (i.e. the execution of the two tasks must overlap, see figure 1).

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.

General methods

In a typical experimental situation the refractory period reflects the slowing in the response time of the second task when the interval intervening between the second and the first task (also called stimulus onset asynchrony, or S.O.A.) is systematically shortened. An example of psychological refractory period might be this one. Task 1 (sometimes referred to as T1) requires to push the keyboard-letter 'n' with the right index finger when a squared frame was displayed in red and to push the keyboard-letter 'm' with the right middle finger when the squared frame was green. Task 2 (or T2) might require to push the keyboard-letter 'v' with the left index finger when the digit displayed was a '3' and to push the letter 'c' with the left middle finger if the digit displayed was a '4'. If the temporal distance between these two tasks is varied, for example 150 milliseconds (ms) and 1000 ms in another, the time to respond to the second task will be longer when the interval occurring between the two tasks is 150 ms than when it is 1000 ms. Referring to figure 1, the SLACK intervening between the execution of the first and second task will be absorbed when the interval intervening between the two tasks is long than when it is short.

Interpretations

A general interpretation of the PRP effect assumes the presence of a bottleneck when initiating responses to stimuli. If we detect a stimulus, and are processing that information whilst a second stimulus comes along we are unable to attend to and process the second stimulus until we have finished processing the first one, thus making our reaction time longer; this extra reaction time is referred to as the psychological refractory period. It is virtually impossible to initiate two responses simultaneously. People can, however, initiate additional responses after the first one has been initiated.

References

• http://aahperd.confex.com/aahperd/2005/preliminaryprogram/abstract_7126.htm