Psychological refractory period

In the research attention is called Psychological refractory period ( PRP, English:. Psychological Refractory Period) a time interval in which only one stimulus can be processed. The term was coined in 1952 by Alan T. Welford.

Basic processes

Even in a psychological laboratory is such a situation to produce. A respondent must react as quickly as possible on two successively proffered stimuli. It then takes the PRP effect of a delay in response to the second stimulus, that is an extension of the reaction time 2 to the second stimulus. The response time to the first stimulus is not extended, remains untouched.

The term refractory period is derived biological or neuroscience of the refractory period. The time is meant the need neurons after stimulus line to get back to transport an action potential. For the PRP, the term effect that neurological processes are involved and it is a delay.

Models of stimulus processing

There are two primary models that try to explain this effect. The capacitance- division model and the delay models. In both models, a fundamental, three-level stimulus processing is believed to occur. After a first phase of sensual, often visual, perception, which depends on the stimulus properties, followed by a stage of central processing. This stage consists of the decisions about the possible modes of reaction and the final determination. In this stage of central information processing stage is followed by a motor. While the capacity -sharing models from a limited pool of processing resources that must be divided among the two tasks, going out, take the delay models of a kind of bottleneck. This bottleneck effect that two of the same steps can not be performed at the same time. This is the explanation for a response delay relative to the second stimulus, because the reaction steps for the second stimulus can not run because the response to the first stimulus has already been started and is currently on a stage. However, the reaction time for the second stimulus is not always extended and the reaction is delayed, therefore, 2.

With reaction time, the time of the presentation of the stimulus ( stimulus onset) is meant to reaction. Decisive for the delay of RT 2 is the interval between the two stimuli. This interval is referred to as the stimulus onset asynchrony, or SOA.

Basically, the following applies simplified scheme. SOA is very short, such an overlap of the two reaction processes ( stimulus on one and two) is very likely. The result is somewhere in the manufacturing process of the bottleneck and thus a break, which is called "cognitive slack ". The SOA, however, so long that the bottleneck stages do not overlap, then runs freely from reaction 2. But this is just a basic consideration. Much more important for the delay theory is the localization of the bottle neck. Depending on the prediction approach should other theoretical constructions. The bottleneck could be either in the motor, the sensory, but also, and this is the most common assumption lie in the central stage of processing. The Different locations can also expect other statistical effects in a statistical review of the results. The three possible effects are:

  • The additive effects under
  • The additive effects
  • The supra-additive effects

To verify the localization must be used to manipulate the various stages of the reaction process. One might assume that a change in the stimulus properties affects the perception level, facilitating the reaction decision takes effect on the central processing. It could be such a relief consist in the stimulus, is to respond to the show on the page on the screen, on which also a button to be pressed.

Conclusions in the research area

The search for the bottleneck based on a number of different experiments, each with different approaches, theoretical explanations and the resulting modes of interpretation.

In addition, efforts are made to effect in relation to other variables such as exercise processes, correspondence of stimulus and Antwortmodalität, physiological processes and, for example psychopathological conditions to check.

Nevertheless, there has been no clear result for the localization of the bottleneck in the processing of two different stimuli.

Two tasks are combined Generally, when reviewing the PRP effect. The single-task - task and dual- task task. The single-task task involves only a single stimulus processing. It is used for calculation of the response time under normal circumstances. One determines this by the stimulus two. The dual -task task is the actual experimental passage. Here occurs the PRP effect.

Sources & Literature

  • Welford, AT ( 1952): The "psychological refractory period" and the timing of high-speed performance - A review and a theory. British Journal of Psychology, 43, 219
  • Pashler, H., & Johnston, JC (1989 ): Chronometric Evidence for Central Postponement in pace Rally Overlapping tasks. Journal of Experimental Psychology 41, 19-45 (1-2).
  • McCann, RS, & Jonston, JC (1992 ): Locus of single-channel bottleneck in dual- task interference. Journal of Experimental Psychology 18.471-484 (1).
  • Attention
  • Neuroscience
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