RA Reaction Time Analysis

With Reaction Time Analysis the slowing down of reactions can be assessed in a differentiated way according to the three stages of activity regulation (perception, cognitive processing and motor response organization. This shall be especially useful for the representation of the course of illnesses in an advanced age. But the RA can also be used as a tool for aptitude diagnostics.

Application
The Reaction Time Analysis (RA) has been developed for the field of clinical psychodiagnostics. However, it can also be applied to the selection process of personnel and to the examinations of therapeutic developments when observing a therapy (diagnostics of individual cases).
The aim is to differentiate the general statement about cognitive speed for tasks of the so-called speed-type regarding individual phases of action control. The phases concerned are perception, cognitive processing, and motor organization of responses. The items used in the test are choice reaction items as well as items of visual search.

Theoretical background
The Reaction Time Analysis goes back to Sternberg's Model of additive factors (Sternberg 1969). According to him there are serial and independent phases in a process, in which the measurable reaction time is the sum of the reaction times of all phases. What varies are the factors which have an influence on the processing time of selective individual phases. The effects caused by the reaction time make it possible to draw conclusions on the reaction time of individual phases. In order to influence the perception phase, the difficulty of discrimination of the figures presented on the monitor (circle, rectangle, square, star, cross, ellipsis) is varied by a grid which partly covers the figures. The variation of the phase of cognitive processing is based on the model of visual search by Schneider and Shiffrin (1977). The authors showed that visual search processes are realized by serial steps of comparison concluded by the respondent him/herself. In the test the respondent has to find one or two specific figures while two figures are presented on the monitor at the same time. This causes a variation of the number of necessary steps of comparison. A variation of the phase of motor organization of responses is achieved by a modification of the complexity of items. (Reaction entered with just one finger or with a sequence of three buttons). This affects the central motor elements of the programming process of responses in the brain (Rosenbaum and Saltzmann, 1984).

Administration
The respondent is guided through the experiment  in an interactive way. The experiment includes 14 Subtests to be carried out with 20 individual stimuli each in choice reaction items, and 16 individual stimuli each in items of visual search.

Test forms
There is a standard test form available.

Scoring
The test is evaluated regarding the following parameters:

• frequency of errors (types of errors are incorrect positive and incorrect negative)
• median reaction time categorized according to the respective test requirements and
• difference of reaction times of comparable test requirements as an indicator
  for cognitive speed in individual phases of action control.

Reliability
The internal consistencies of all the scales are situated between .85 and .99 and can be considered very satisfactory.

Validity
The Reaction Time Analysis was carried out while simultaneously deducing event-related brain potentials (ERP)(Dormann, Pfeifer, Nickel, 1991). It was shown that varying test requirements which influence the stimulus assessment time (perception phase, phase of cognitive processing) also result in a prolonged peak time of the late positive complex in ERP (P 300). On the other hand, varying test requirements which are effective after stimulus assessment (this concerns motor sequence for influencing a phase of motor organization of responses) do not result in differences in peak time of P 300. Thus the phase model was basically corroborated. Furthermore, findings for a deceleration caused by old age as well as a deceleration of the organic psychosyndrome were corroborated by comparative examinations.

Norms
It is possible to compare results with a comparative sample categorized into various relevant groups (age, level of education, N=162).