Lecture
The verification and falsification of hypotheses makes it possible to introduce such a criterion of distinction as thought experiments versus actually conducted experiments.
Falsification, i.e. rejecting a hypothesis as incorrect, may be based not only on an actually conducted experiment, but also on substantive-logical arguments in interpreting the expected dependencies. Verification, i.e. accepting a hypothesis as corresponding to reality, is possible only on the basis of obtained empirical data, i.e. in a real experiment.
An experiment conducted for the purpose of obtaining empirical arguments for or against the understanding of a psychological regularity assumed in a substantive hypothesis is called a real (actually conducted) experiment. It is contrasted with the thought experiment, which makes it possible to assume that certain data would be obtained under controlled experimental manipulations, but these assumptions are not realized in the researcher's practical activity. The thought experiment is directed at justifying a particular decision about the type and mechanisms of the presumed regular connection between the IV and the DV. In a thought experiment there is the realization of a single path to conclusions about a dependency, whereas in a real one there are several paths (at least three).
The advantage of thought experiments is the possibility of assuming that a dependency can be established in the absence of confounds. Here no real control of confounds is needed; one can assume ideal conditions and mentally model the basic processes under study in any of their manifestations (even if no real methods exist). Here there is no need to relate the result of the action of the IV to an assessment of internal and operational validity.
One should distinguish between the concepts of «thought experiment» and «mental model of an experiment». The thought experiment is:
1) the accepted norm of reasoning at all stages of hypothesis testing;
2) a thought experiment in the context of a psychologist's use of mental models for the purpose of controlling threats to the conclusion about an empirical dependency;
3) a thought experiment – an experiment that cannot be realized because of the absence of means for operationalizing the variables.
In the first two cases, the path of thought experimentation is the discussion of an experimental model that specifies the connection of interest between the variables.
The third case is an «unreal experiment» (see above).
Hypotheses tested in a thought experiment: causal, structural-functional.
Functions of the thought experiment: planning, justifying, and assessing the validity of actually conducted experiments.
Mental models of an experiment are criteria in relation to which various aspects of the validity of actually conducted studies are discussed.
1. The ideal experiment (only the levels of the IV affect the DV, there are no other changes, no confounding variables) – internal validity
2. The infinite experiment (internal validity)
3. The experiment of full correspondence (for assessing external validity)
4. The flawless experiment (a synthesis of the previous three)
(see Gottsdanker).
Population hypotheses, which aim to transfer generalizations to specific groups of people and to entire populations, can be assessed with the help of mental models, but cannot be tested in the mental plane.
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