Lecture
Experimenter effects. (The personal traits of the experimenter overlay the personal traits of the participant; the influence of the expectations and attitudes of the participant and the experimenter, and so on.)
The participant effect: volunteers and clients. The actualization of the «motivation to be evaluated».
The experimenter is involved to varying degrees in conducting the experiment and in communicating with the participant. For example, the use of projective techniques requires greater involvement than the use of standardized questionnaires.
These factors are usually considered at the stage of primary control and in assessing the representativeness of the data. Experimenter effects may serve as sources of both systematic and nonsystematic confounds.
These effects must be examined in the context of the experimental material, i.e., the task factor.
Four characteristics of tasks that promote the manifestation of experimenter effects: 1) the experimenter's participation in the participant's activity; 2) the ambiguity of the tasks; 3) the difficulty of the tasks; 4) the correspondence between the nature of the task and the experimenter trait under consideration.
Rosenthal: the Pygmalion effect. The experimenter's involuntary facilitation of the manifestation of those regularities in whose truth he is convinced (confirmed in studies of nonverbal communication between the participant and the experimenter – smiling, and so on).
The study of these problems gave rise to «centaur designs», in which the task factor is varied in an intra-individual sequence, while the personal trait of the experimenters or participants is controlled by selecting groups that differ on a given trait.
The experimenter effects can be illustrated with the material of
Johnson's experiment.
It tested the hypothesis that the heightened orientation of women with certain personal traits toward the behavior of a male experimenter leads to the actualization of sexually tinged associations in them while performing tasks. There were two groups: the experimental one – women with a hysterical accentuation, and the control one – without accentuations. The experimental manipulation was expressed in the prescribed «seductive behavior of the experimenter» (he paid compliments, touched the young woman's arm while leading her into the experimental room). In the control condition he did nothing. (That is, we have four kinds of situations.) Next, the participants had to perform tasks on the visual recognition of ambiguous material (neutral and sexually tinged) and to learn paired associations. In the group of «hysterical» women, verbal learning proceeded significantly faster with sexually tinged associations, especially under the experimenter's seductive behavior. But in the control group, such behavior of the experimenter had no effect whatsoever on the results. That is, here we see how the participant effect overlays the experimenter effect, and together they lead to a change in the results.
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