Equipment for Assessing Basic Processes

Introduction

Cognitive processes as information processing, reasoning, and the awareness of subjective experiences are unobservable. Usually the objects of cognitive research are reconstructions derived from controlled observations of settings, instructions and stimuli as well as from responses such as motor reactions, decisions, kinds of trials in problem solving and verbal reports (Monsell & Driver, 2000). The main goal is to describe sequences of steps in cognitive functioning with respect to genetic, skilled and actual causes of the occurrence of responses and their chaining.

General Remarks on Measures in Cognitive Research

Cognitive behaviour is setting-dependent. Effects of bodily position (unusual or rotated views) are observed for recognition effects and for the extent of optical illusions. Certain environmental circumstances in a study phase (classroom setting, weightlessness) might be part of elaboration and associative chaining.

Instructions on how to deal with a target stimulus can be given in a multitude of ways. Mostly they act as a cue to prime certain associations in preparing how target information should be processed. The simplest kind of cues are so-called peripheral cues which are close to the target in space and time. Symbolic or exogenous cues are more remote from the stimulus features; mostly verbal instructions are used in these cases. Effectiveness of instruction is often strengthened by a training phase up to a compliance criterion.

Stimuli are certain changes in the environment, affecting one or more senses. Because cognitive research is mostly based on assumptions on a sequence of cognitive operations (mental chronometry), a precise control of stimulation is needed, such as time relation to cues, onset, extent and comprehensibility. Standardized stimulation needs suitable devices, such as monitors, earphones, or skin stimulators.

Experiments are often designed to measure knowledge or ability, or to measure concomitants (such as emotional, psychophysiological, or neurological processes), or to measure time up to the correct response. Sometimes, frequency or types of errors or the ways of responding are assessed. To avoid uncontrolled influences by chance, reaction is usually restricted by instruction. Choice reactions can be restricted by forced choice and can be realized between two or more alternatives.

An elementary decision is to decide dichotomously as between confirmative or non-confirmative (signal detection theory – SDT). In this case, four response classes are considered (hits, misses, correct rejections and false alarms), usually according to fixed criteria (right or wrong). To evaluate performance in SDT paradigms, a large number of responses and special procedures are required (Snodgrass & Corwin, 1988). Most of cognitive research is done by the use of certain materials for testing failures and errors. Apart from psychophysiological methods of error processing, [Page 370]evaluation and back propagation of failures (e.g. automatic feedback presentation by PC) is commonly used in research on concept formation.

Responding is most restrictive in so-called go-no go paradigms. An often-used example is the odd ball paradigm. Here, usually two classes of stimuli are presented for go-no go in a time series, instances of one class with a low frequency.

Responses can be realized by verbal or by nonverbal output, e.g. movements. In both cases, special equipments for response detection are used, especially in time-critical designs. Motor responses such as writing, drawing, or marking with a cross are often required. Sometimes one has to move a joystick, to press a handle or a key, or has simply to move a finger. In measuring reaction times, movement detection and evaluation are serious problems.

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