Variables in Psychological Research
Variables
In
Psychological Research
Webster says that a variable is "a thing that is changeable" or "a quantity that may have a number of different values."
In psychology, the variables of interest are often behaviours or causes of behaviours. Many psychologists have adopted a theoretical viewpoint or model called the S-O-R model to explain all behaviour.
The symbols S, O, and R represent different categories of variables.
"S" is the symbol of stimuli, and the category may be referred to in general as stimulus variables. A stimulus variable is some form of energy in the environment. Such as light, to which the organism is sensitive.
"O" is the symbol for organismic variables --- the changeable physiological and psychological characteristics of the organisms being observed. Example of such variables are anxiety level, age and heart rate.
Finally, "R" is the symbol for response and, in general, response variables, which refer to some behaviour or action of the organism. Saying "yes", running and pressing a lever are examples of response variables.
However, a behavioural scientist attempts to define a variable more precisely and specifically. Kerlinger (1964) has defined variable as a property that takes an different values.
According to D'amato (1970) variables may be defined as those attributes of objects, events, things and beings, which can be measured. In other words, variables are the characteristics or conditions that can be manipulated controlled or observed by the experimenter. Sex, IQ, level of aspiration, anxiety, coping strategies, socio-economic status, and achievement etc. are examples of variables commonly employed in Psychological research.
● CLASSIFICATION OF VARIABLES ●
A variable can be classified in a number of ways. The classifications have been done from looking at variables in three different ways :
1. The causal relationship
2. The design of study
3. The unit of measurement
1. From the viewpoint of causation :-
(i) Change variables, which are responsible for bringing about change in a phenomenon. In psychological research, change variables are called "Independent Variables".
(ii) Outcome variables, which are the effects of change variables. Outcome/effect variables are called "Dependent Variables".
(iii) Variables which affect the link between cause and effect variables. These unmeasured variables are called "Extraneous Variables".
(iv) Connection or linking variables, which in certain situations are necessary to complete the relationship between cause and effect variables. These variables are called "Intervening Variables".
☆ Independent Variables : An independent variable is that factor manipulated by the experimenter in his attempt to ascertain it's relationship to an observed phenomenon.
Depending upon the mode of manipulation some experts have tried to divide the independent variable into : type - E independent variable, and type - S independent variable (D'Amato, 1970).
Type - E independent variable is one of which is directly or experimentally manipulated through the process of selection only. For example, the experimenter wants to study the effect of noise upon the task performance in an industry. Here the independent variable is the noise and the department variable is the task performance. He may manipulate the noise by dividing into three categories --- continuous noise, intermittent noise and no noise; and examine its effect upon task performance. Here the noise is being directly manipulated by the experimenter and hence, it constitutes the example of type - E independent variable.
Suppose, the experimenter is interested in answering the question: is the rate of production dependent upon the age of the workers? Age is here the type - S independent variable.
To investigate this problem, the experimenter will have to select groups of workers on the basis of their age in a way by which he can get an appropriate representation from different age groups ranging from say, 16 to 55 years. Subsequently, he will compare the rate of production obtained by each age group and finally, conclude whether or not age is a factor in enhancement of the performance.
☆ Dependent Variable : A dependent variable is that variable which appears, disappears, or removed or varies when the experimenter manipulates and changes the independent variable.
For example :
▪Hypothesis 1: As the number of trials increases errors decrease.
▪Independent Variable: number of trials.
▪Dependent Variable: Errors committed by the subject.
☆ Extraneous Variables : Several other factors operating in a real life situation may affect changes in the department variable. These factors, not measured in the study, may increase or decrease the magnitude or strength of the relationship between independent and dependent variables.
☆ Intervening Variables : Intervening variables sometimes called the confounding variables (Grinnell,1988- 203), links the independent and dependent variables. In certain situations the relationship between an independent and a dependent variable cannot be established without the intervention of another variable. The cause variable will have the assumed effect only in the presence of an intervening variable.
2. From the Viewpoint of the Study Design :-
☆ Active Variables : A variable which is manipulated by the experimenter is the active variable. Example of active variables are reward, punishment, methods of teaching etc.
☆ Attribute Variable : A variable which is not manipulated but measured by the experimenter is the attribute variable or organismic variable. Some of the examples of attribute variables are age, sex, intelligence, race, anxiety, etc.
3. From the Viewpoint of The Unit of Measurement :-
☆ Qualitative and Quantitative variables: The quantitative variables refers to those variables which consist of categories that cannot be ordered in magnitude. We cannot make such a statement regarding the qualitative variables, e.g., "category X possesses higher (or lower) magnitude of the variable than category Y."
Sex, race and religion are examples of qualitative variables. The qualitative variables refer to those variables which are composed of categories that can be ordered in magnitude. Intelligence, age, levels of illumination, intensity of sound etc., are the examples of quantitative variables.
☆ Continuous Variables and Discrete Variables : Quantitative variables are further divided into two categories, namely, continuous variable and discrete variables. A continuous variable is one which is capable of being measured in any arbitrary degree of fitness or exactness. Age, height, intelligence, reaction time, etc., are some of the examples of a continuous variable. The age of the person can be measured in years, months and days. Thus, all such variables which can be measured in the smallest degree of fitness, are examples of the continuous variable.
Discrete variables (also known as categorical variables) are those variables which are not capable o being measured in any arbitrary degree of fitness or exactness because the variables contain a clear gap. For example, the number of members in a family constitutes the example of a discrete variable.
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