Lecture
Psychological hypotheses and explanations are specific, which means that the approach must be modified, namely:
- Certain assumptions must be made about the type of experimental influence;
- The use of the means of formal planning is modified (as a result of the different construction of theoretical knowledge and the specificity of psychological variables)
- Substantive planning likewise cannot be reduced to the standards that are applied in testing natural-scientific hypotheses.
The psychologist can reconstruct, that is, mentally recreate, on the basis of observable and recorded indicators, those psychological processes that are inaccessible to observation.
What is common in the implementation of the experimental method: the psychologist uses the accepted standards for testing causal hypotheses; in substantiating a causal explanation, the psychologist adopts those aspects of the attitude toward subjective reality as an object of study that Polanyi called personal knowledge.
The experimental method in psychology is a hypothetico-deductive line of reasoning in the testing of causal hypotheses.
The hypothetico-deductive path: the transition from general statements about theoretical dependencies to the advancing of empirically loaded hypotheses about the consequences of the operation of laws, consequences that can be recorded.
Standards:
A hypothesis that follows from the theory is tested (empirical loadedness)
Correlating the hypothesis with the empirical data at the level of «modus tolens»
- falsification (refutation)
- verification (availability for further testing).
The presence of a counter-hypothesis. That is, there must be an equal probability of obtaining data both for and against the theory.
[( pq) & not-q] not-p
q is the data; p is the generalized statement
Conditions of causal inference:
- A cause can only precede its effect.
That is, variable X must precede variable Y in time.
In psychology there are also other conceptions of causality, in the context of which this condition may not hold. (K. Lewin: dynamic causality; Piaget: synchronic causality).
- Covariation (a lawful relationship) between the DV and the IV
Manipulation of the IV takes on the forms of functional control of conditions in the experiment and makes it possible to move to conditional statements of the form «if…then…».
- The absence of competing (third) hypotheses.
That is, the elimination of threats to the conclusion that X affects Y from other explanations of changes in Y (explanations by «third variables», for example).
Confounding (extraneous) variables must be adequately controlled – accompanying or systematic changes of variables not included in the hypothetical relationship between X and Y. Otherwise there is a threat to internal validity.
The problem of interpreting psychological causality is closely connected with the theoretical attitudes and methodological positions of authors regarding the construction of psychological explanation.
The need to distinguish between levels of hypotheses.
The experimental hypothesis pertains to empirically established regularities; the theoretical hypothesis establishes a principle of explanation proceeding from the propositions of one or another psychological theory.
The deductive path is contrasted with the inductive one.
An experiment cannot confirm the correctness of a theoretical hypothesis by an inductive path, that is, by extending the conclusion «from the particular to the general».
Inductive laws are used in empirical research at the stage of planning the experiment, when the researcher compares situations with and without the introduction of influencing variables, which distinguishes these situations as control and experimental conditions.
The formal planning of experiments is based on inductive principles, but the inductive inference concerns not the content of the hypothesis, but the conclusion about the possibility of regarding the IV as the main condition producing the experimental effect. These principles were developed in inductive logic by J. Mill.
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