METHODS OF EDUCATIONAL PSYCHOLOGY
Educational Psychology is the scientific study of the behavior of the learner in relation to his educational environment. Behavior in all its aspects can be studied scientifically through a single technique or approach known as observation. This leads us to the simple conclusion that observation may be regarded as the only method or technique for concluding studies of behavior. This single technique or approach however gives rise to several methods or approaches, depending upon the condition in which observations have to be recorded, the procedure adopted and tools used. We will discus this aspect now. Observation or one’s own behavior by looking within or looking inward may be adopted as one of the approaches. Such an approach is known as the method of introspection.
Sometimes behavioral events are observed and recorded under natural conditions by some person or persons. Such observational approach is termed as naturalistic observation.
This is the oldest known method for the study of behavior. In the early days of the evolution of Psychology, behavior was studied only through a kind of self-examination of inner observation called introspection. The word ‘introspection’ is made up of two Latin words, intra meaning “within” or “inward”, and spiere, meaning to “look”, Hence, introspection means looking within or looking inward. In introspection then, one is required to get inside one’s own mind. It is a sort of self-observation in which one perceives. Analyses and reports one’s own feelings and, in fact, everything that takes place in one’s mind during the course of a mental act. For example, when in a state of anxiety, fear or anger. one may be asked to determine by one’s own observation what one sensed, thought or felt at the time of experiencing that emotion.
Introspection-the observation and reporting of one’s own mental processes-is considered important on account of its unique nature. It is a simple and readily available method. One’s mental processes are always present and can be introspected at any time. Introspection is, therefore, able to give us a direct and immediate insight into one’s own mental processes without involving any extra expenditure of material or apparatus. Moreover, introspection provides adequate knowledge of the inner or covert experiences and thus the inner behavior of an individual in the form of thought or feeling can be revealed through introspection.
Drawbacks and Limitations
Introspection as a method of studying behavior, however, suffers from some serious drawbacks and limitations: In introspection one needs to observe or examine one’s mental processes carefully in the form of thoughts, feelings and sensations. The state of one’s mental processes is continuously changing. Therefore, when one concentrates on introspecting a particular phase of one’s mental activity that phase passes off. For example, when one gets angry at something and afterwards sits down to introspect calmly or to self-examine the state of anger is sure to have passed off and so what one tries to observe is not what is happening at that time with oneself but what had happened some time before. Introspection as a method of serious study lacks in reliability, validity and objectivity for the following reasons:
(a) The results lack reliable communicability and repeatability because any one investigator can never be sure that what he feels or senses is the same as is experienced by other investigators. If we invite introspection reports on the nature of the sensation of green for example, these reports are bound to differ. Some will insist that green is a unitary sensation, whereas others may say that green is a mixed
sensation involving yellow and blue. We have no means for the objective observation of the introspection phenomenon. Moreover, in introspection one studies one’s own behavior or mental process. It is not possible to verify self-observation as one’s own mind cannot be studied by others in introspection.
(b) It is next to impossible to acquire validity and exactness in self observation or examination of one’s own mental process. The mind in perceiving its own functions tries to divide itself into two halves-the subject and the object. The object of observation and the instrument of observation are of course one and the same. This automatically affects the validity and exactness of the observation process and the perceived results. A man who is angry or afraid cannot observe exactly what is going on in his mind and remain unchanged in his emotional state of anger or fear. The consciousness on his part is sure to affect his mental or emotional state which is the object of observation. The scope of introspection as a method of studying behavior is rather limited. It can only be applied satisfactorily in the case of adult normal human beings. The behavior of children, abnormal human beings, animals etc., cannot be studied by this method.
Thus, if we try to evaluate the introspection method we find that it is based on self-speculation, lacks reliable communicability, replicability and reasonable exactness or precision. It is neither sufficiently scientific practicable nor simple enough to handle. It cannot therefore be taken as an adequate or sufficient single method for psychological studies. The conclusions arrived at by this method need to be supported by specific scientific findings through some other objective and reliable method.
Observation as a method of studying behavior consists of the perception of an individual’s behavior under natural conditions other individuals and the interpretation and analysis of this perceived behavior by them. It is thus essentially a way of ‘perceiving the behavior as it is. By this method we can infer the mental processes of others through observation of their external behavior. In fact it is an indirect approach to the study of the mental process. If some one frowns, howls, grinds his teeth, closes his fists, by observing the external signs of his behavior we can say that he is angry. But to study this behavior concerning anger in natural conditions, one has to wait for the event to occur. Similarly, to study the behavior of students in a crowd or during a strike, and the behavior of a delinquent or problem child, the psychologist has to wait till the particular behavior occurs and then use all his resources to observe record, analyze and interpret the behavior from what he has perceived under natural conditions.
The observation method occupies a prominent place in the study of human behavior. It is natural, flexible and economical. Its results are reliable and can be verified. The natural observation method is particularly suitable for studying the developmental characteristics of individual children’s habits, interests and other personality traits. For example, the effects of the absence of one or both parents on a child s development can be determined properly through observation of his development. Similarly, a clinical psychologist may be able to collect the required data about the abnormal behavior of an individual by observing him under natural conditions of his day to day life.
Drawbacks and Limitations
The observation method cannot be termed as sufficiently objective, reliable and valid for the following reasons: It can prove useful only for collecting data on the observable behavior of an individual. It is impossible, to observe what is happening in the mind of others, and so reasoning can only be through external behavior. It is possible that a person may be expert at hiding his feelings and emotions and disguising his evil nature under the cover of artificial sobriety. In such cases the method of observation fails to judge the true nature of the individual concerned. Subjectivity factors on the part of the investigator as well as in the process of observation also affect the results of observation. There may be distortions of observable factors depending upon the observer’s degree of care in observation. His interests, values, and prejudices may also distort the contents and results of the observation. He may lay extra emphasis on one part of one’s behavior and may altogether neglect some other very important aspect. The interpretations of the recorded events may also be similarly colored. One may read one’s own thoughts, feelings and tendencies into others’ minds. The lacunae resulting from such subjectivity may, however, be corrected to a certain extent by having as many observers as possible for observing the same phenomenon and employing scientific instruments such as a tape recorder, or a video camera etc., for recording the events. Another serious limitation of the observation method is that the behavior observed is dependent on the time and place and on the individual or group of people involved. It lacks replicability as each natural situation can occur only once. Another important limitation of the observation method lies in its inability to establish a proper cause and effect relationship. If two phenomena, say poverty and delinquent behavior, invariably occur together, it cannot be established that poverty is the sufficient and necessary cause of delinquent behavior or vice versa.
The experimental method is considered the most scientific and objective method of studying behavior. It lays emphasis on performing experiments. The word ‘experiment’ comes from a Latin word experimentum meaning ‘a trial’ or ‘test’. Therefore, in experimentation we try or put to the test the material or phenomenon whose characteristics or consequences which we wish to ascertain. In the sciences, while conducting such experiments in the laboratory or outside in a natural environment we may want to learn the effect of friction on motion, the effect of sunlight on growth of plants, etc. In educational psychology also, we perform such experiments in the psychological laboratory, class-rooms or outside the classrooms in physical or social settings to study the cause and effect relationship regarding the nature of human behavior, i.e. the effect of anxiety, drugs or stresses on human behavior, the effect of intelligence or participation in co-curricular activities, on the academic performance of students, etc. In performing all such experiments we try to establish certain cause and effect relationships through objective observations of the actions performed and the subsequent changes produced under pre-arranged or rigidly controlled conditions. From these observations certain conclusions are drawn and theories or principles are formulated. The essential features of the experimental method are: Experiments performed in this method essentially require two persons, the experimenter and the subject or the person whose behavior is to be observed. These experiments are always conducted on living organisms in contrast to experiments in the physical sciences which are generally conducted on inorganic or dead subjects. The key factor in this method is the control of the conditions or variables. By this control we can eliminate irrelevant conditions or variables and isolate the relevant ones. We thus become able to observe the causal relationship between two phenomena, keeping all other conditions al most constant. For example, if we try to study the effect of intelligence on academic achievement by the experimental method, we will need to determine the causative relation between the two phenomena (variables)-intelligence, and academic achievement. One of these variables, the effect of which we want to study, will be called the independent variable and the other the dependent variable. Thus the independent variable stands for the cause, and the dependent variable is the effect of that cause. Other conditions like study habits, sex, socio-economic conditions, parental education home environment health, past learning, memory, etc., which exercise a good impact upon one’s achievement. As already emphasized in the experimental method experiments can be performed in the psychological laboratory or in the class rooms or outside the class-rooms under rigidly controlled conditions. Let us discuss how these experiments arc performed.
Experiments in the Laboratory Set-up
Just like other physical or natural sciences, experiments can be performed In Psychology or Educational Psychology for studying the behavior in the actual laboratory set-up. Thorndike’s experiments on cats, Pavlov’s experiments on dogs, Skinner’s experiments on rats and pigeons and their experiments to study the behavior related to learning. transfer of learning, memory, a ttention, perception etc., arc all examples of 511 h laboratory experiments.
Experiments Outside the Laboratory Set-up
In Educational Psychology experiments can also be conducted without involving the usual psychological laboratory set up. However, for such studies, there is need of some special experimental designs for controlling the variables and measuring their effects. A few of such designs are:
1. The control test or single-group design. In these design it is not necessary to have two different individuals or group if subjects for the experiment. Here a single individual group or individual can work as the subject for the experiment. The subject whether an individual or a group of individuals, is first objectively observed under normal condition and then under different sets of changed conditions. As another illustration we may conduct an experiment to ascertain whether a group of students can do better in an intelligence test under the influence of a specific drug like benzedrine sulphate or caffeine. For this investigation, we will take only one group of some students, preferably of the same age, sex and state of health. The procedure of the experiment will comprise the following steps:
(a)These students can be given sugar capsules after which they can be put through some intelligence test. This will provide the initial testing under normal conditions.
(b)Some time later, they can be given drug capsules and tested on the same intelligence test. This will make a test under changed conditions.
(c)The l.Q. scores under these two situations are noted down and the difference is calculated. 1f any significant difference is found, it will be attributed to the influence of the drug.
- Control-group design. The control test or the single group design method has a serious drawback known as the positive practice effect. If an individual is subjected to a certain kind of fear stimulus, it will surely affect the responses on his further exposure to fear stimuli. If a group is subjected to a certain drug, then it will automatically carry its effect or influence at the time of the introduction of some other drugs at the later stage. Control group designs help in minimizing such a practice effect. In the control group design two separate groups, known as the experimental group, and the control group, participate in the experiment. They are equated or matched on various traits like age, sex, intelligence and other personality characteristics. There is a one-to-one correspondence in the two equated groups. Now the control group is given sugar capsules and tested on some intelligence test. At the same time, the experimental group is given the drug capsule and tested on the same intelligence test. The differences in the intelligence scores of the groups are then calculated. In case some significant differences are found, they are attributed to the effect of the drug.
- Multiple-group design. Sometimes, we have to experiment with more than two groups for arriving at the appropriate conclusion. For example, if we want to study the effect of knowledge of English on the speed with which people subsequently learn French, we decide to teach English to a group of students and then see whether they learn French more easily. But more easily than whom? Certainly we will need another group, or groups for comparison. Group A, consisting of students who have learnt the English language is called the experimental group. Group B may function as a control group for comparison, since it did not learn English earlier. If group A learns French faster than Group B can we attribute the difference in speed to the earlier study of English? Certainly not. It may be that practice on account of learning any subject or language may have the same positive transfer effect. To rule out these possibilities it is essential to add some more control groups like C and D. Now if group A demonstrates a clear superiority over the other three groups, then and only then may we infer that learning English facilitates learning French. For illustration, the working of a multiple group design for data collection in the present case may be tabulated as shown. Group Subject for rest held in the month of August Test held in the month of February A B C D English No rest .Any subject (say Mathematics) Russian French French French French
4. Designs involving rotation. This experiment involves presenting two or more stimulating situations to the experimental subjects in as many sequences as necessary to control the serial effects of fatigue or practice. For example, if we want to determine the relative influence of two specified conditions A and B (say praise and blame) on a group of subjects, we will not measure all the subjects under condition A and then under condition B. Condition A might cause fatigue or so train the subjects that the measures under condition B would not be independent of the fatigue or training effects. Here two alternatives can be adopted:
(a)We may obtain half the measures for condition A, all the measures for condition B, and then the other half of the measures for condition A. This technique is sometimes called the A B B A order.
(b)Another alternative is to separate the subjects into two equated groups, one of which receives treatment A and then B, whereas the other group receives treatment B and then A. Both sets of A results and both sets of B results may then be combined and the difference between them calculated.
Limitations of the Experimental Method
The Experimental method advocates the study of behavior under completely controlled rigid conditions. These conditions demand the creation of artificial situations or environment and the behavior studied under these conditions may be or is usually different from the spontaneous or natural behavior. Therefore, the experimental method fails to study behavior in natural conditions as may be possible through natural observation. The second limitation or difficulty lies 10 exercising actual control or handling of the independent variable and the intervening variables. It is very difficult to know and control all of the intervening variables. Similarly we cannot always control the independent variable. Therefore it is not always possible to create the desired conditions in the laboratory and consequently, in the absence of these controlled conditions the success of this method becomes quite uncertain. 3- In the experimental method we often make use of animals or birds as subjects for experimentation. It is also debatable whether experimental results obtained from such sources are applicable to human beings at all. The scope of the experimental method is limited. All problems of psychology cannot by studied by this method as we cannot perform experiments for all the problems that may come up in the diverse subject matter of psychology. The dynamic nature and unpredictability of human behavior does not always allow the independent variable to lead to change in the dependent variable. Human behavior is not a mechanical behavior. The anger or fear producing stimuli or variables mayor may not yield the required responses as desired under experiment and hence it is not possible to get uniform responses or changes 1n the dependent variables on account of the concomitant changes in the independent variable. The experimental method is a costly and time consuming method. Moreover, the conduct of experiments under this method requires specialized knowledge and skills. In the absence of such specialized abilities, it is not possible to use this method.
The differential method is based on individual differences. Therefore, all the measures applied to the calculation of individual differences are included in this method- The differential method is also named as the normative survey method or the field survey method as the investigator has to go to the field to make his investigations. It is sometimes called the statistical method for the reason that statistical techniques become the major devices for the study of the individual differences. Now, the question that arises is, how do differential methods differ from experimental methods? It may be felt that the difference between the experimental and differential methods is only arbitrary and artificial, since the procedure of finding the effects on dependent variables by the application of the independent variables is the same. This however is not true as T.G. Andrews (1958) comments: Differentiation between experiments and differential methods may appear quite artificial, and it is true that all psychologists will not agree to such an apparently artificial classification scheme.
Nevertheless it should always be made clear that the independent variables resulting from individual differences are never under the investigator’s control to the same degree that experimental variables are. Thus, differential methods differ from the experimental approach in that the investigator cannot intentionally manipulate the variables and each of these is studied as an independent variable. For instance, in studying the relationship of achievement with intelligence it is not possible to manipulate intelligence. Therefore, we have to take each individual and study his achievement in relation to his intelligence. After that, we can try to achieve at certain conclusions with the help of statistical techniques. The key concept in using the differential methods is their technique of studying differences within the same individual or between individuals in different groups. Usually for this purpose four types of main approaches or designs are used.
The concept of a clinical method is included in the concept of clinical psychology which is the art and technology of dealing with the adjustment problems of the individual for purposes of his optimum 50cial adjustment and welfare. The analysis of this definition may help us to observe some of the characteristics of the nature and working of the clinical method: The clinical method IS applicable [0 an individual. The individual has some problems. Methods or both diagnosis and treatment are involved in dealing with these problems. The clinical method is inclined al seeking the maximum adjustment and welfare for the disturbed person. The clinical method IS an art as well as in science and technology which means that everybody cannot treat every patient and it takes pleasure III making mankind healthier and better. Thus the basic elements in this method of psychological investigation are the diagnosis and treatment of the problem or mental illness of an individual.
Method of Diagnosis
Diagnosis by the clinical method requires a symptomatic account of the overall situation in order to ascertain the root cause of an illness or behavioral problem. For such diagnosis, one has to look into the past events or experiences of the individuals, their impact and reactions the present environment and adjustment problems, and the total personality make-up, etc. For ascertaining all about these aspects the following techniques are generally employed. Adequate physical check-up the individual suffering from a behavioral problem must be made to go through a detailed physical check-up to ascertain whether the behaviour exhibited of a functional or of an organic nature. In case there are no physical causes for the behavior in question then and only then should it be diagnosed as a subject for psychological treatment.
Making Out the Case History. For finding the clues or developing into the events from the earlier experiences of the individual which may be responsible for the present behavior, the psychologist then tries to use the case history technique. In this technique information is collected from the memory of the individual, his parents, and the members of his family. His relatives, guardians, neighbor, friends, teachers, doctors and from the available records and reports concernH1g the individual’s past for collecting the relevant information the following sources may be used:
(a)Identifying may contain the name of the individual, his father’s name, his residential address, date of birth, caste, religion, nature of exceptional or abnormal behavior etc.
(b)Environmental background this may contain information about the members of the individual’ family, his parents, their relationship with each other, and behavior the subject (individual) of the study, the educational and socioeconomic status of the family, the accidents and incidents which may have occurred In the family, the types of neighborhood, friends and socio-cultural environment, the type of school education and school or Job situation environment etc., he may have passed through
(c)Developing Story. This may con tam the history of the growth and developmental process of the individual In relation to the treatment behavior and environmental facilities availably from birth onwards, history of his mental and physical healthy education and occupation, social and emotional adjustment sex-life etc.
(d)History of exceptional. This may contain all the relevant information regarding: the development of the behavior in question up to the present stage.
- The clinical interview. Additional but very important information may be obtained by the investigator by arranging a clinical Interview with the individual. For this purpose he may carefully plan appropriate questions and persuade the individual to give free and frank responses by establishing the necessary rapport. For understanding the inner working of the individual’s mind, he may be given the opportunity to talk about himself in the interview session. From these responses, the investigator may draw conclusions for the diagnosis of the root cause of the behavior.
- Direct observation of behavior. Direct observation of the behavior of the individual by the Investigator in the natural set-up, living and working conditions may prove quite useful in knowing the nature and causes of the behavior. In the case of children direct observation of the subject at may provide a useful means of understanding him, his behavior and his problem.
- Using tests and measuring devices. Certain testing and measuring devices may also be used to ascertain the interests, abilities, attitudes, aptitudes and the total personality of the individual and relevant Information may thus be obtained for understanding the individual and his behavior.
Method of Treatment
In order to serve the welfare of the individual. diagnosis should be followed by treatment. Fur the treatment of a behavioral problem, efforts are to be made to bring about a change in the behavior of the individual by his adjustment with himself and With his environment and thus ultimately restore hi..; normal mental health. This can be usually accomplished in two modifying the environmental forces 2. Modifying the individual’s attitude. The physical and socio-cultural environment of the individual needs to be modified in such a way that he may not be subjected to further disharmony and maladjustment. Rather, he should be able to get a pleasant and encouraging environment characterized by wholesome and harmonious relationships with other social beings and he should get enough opportunity for the fulfillment of his basic needs. For this purpose the following measures may be adopted. He may be physically removed from one situation and placed in another, like a boarding hOlise, foster home or with guardians and adopted parents, The attitude of the parents, teachers and others toward him may be changed. More adequate recreational facilities, better living conditions, work placement and working conditions may be provided or some suitable measures for the sublimation and catharsis of repressed desires and wishes may be taken. A complete modification of the individual’s philosophy of life is required for bringing about a change in his behavior. He must be made to harmonise his thinking feeling and doing. For this purpose, the following measures may be adopted: Guidance and counseling Psychoanalysis Techniques like auto-suggestion hypnosis, psychodrama and role playing 4, Therapies like psychotherapy, group therapy, play therapy, occupation therapy attitude therapy etc.
The above discussion regarding the nature and working of the clinical methods may lead us to conclude that clinical methods in all their shapes and forms are always concerned with the diagnoses and treatment of adjustment problems or mental and psychological illness of the individual. lt is however, not necessary that clinical methods should always be used to study or treat the mental illness or abnormal behavior of an individual. The real purpose of clinical findings is to help in conducting an intensive and thorough study of the behavior of the individual. Therefore, it does not matter whether we carry out the study of a normal or abnormal behavior with the help of a clinical set-up. There is no bar to study the behavior of normal persons or even exceptional individuals like high achievers, creative geniuses, saints, social workers and leaders by employing clinical methods of collecting relevant information through various means, whether an individual requires treatment or follow-up depends upon the case under clinical study. A clinical study thus does not necessarily require resort to methods of treatment. The treatment can be affected only when the individual under study needs it. Therefore, broadly speaking, clinical methods may be taken as the methods of studying the behavior of an individual in all possible detail relevant to the purpose of the study.
Merits and Demerits of Clinical Methods
The chief merit of the clinical methods is that they can be safely employed to study the particular or specific behavior of an individual. No two individuals are alike in their behavior patterns and a real study of human behavior can, therefore, only be made through a personal and individual study of every human being. Clinical methods provide an intensive study involving all possible details regarding individual behavior. Therefore, as far as true investigation of individual behavior is concerned nu method can match the efficiency and usefulness of the clinical methods. Their usefulness is further enhanced when they provide valuable information regarding the adjustment or behavioral problem of the individual and subsequent suggestions and measures, for the treatment and solution of these problems. Clinical methods thus render signal service to mankind. Their main limitation or drawback is that their proper use demands a lot from the clinical researcher. He should be mature and technically proficient in handling such studies. He cannot involve his own self and personality make-up while diagnosing and treating the individual in his charge. The other limitation is related to the very restricted scope of such studies as the effort put into, and the findings of these studies cannot be generalized. These are meant only for individual cases and end with the diagnosis and treatment of the individual cases under study.
The branch of psychology which is concerned with the study of the relationship between physical and psychological phenomenon is called psycho-physics. In this sense the term ‘psycho-physical methods’ may be used to refer to all those methods in which attempts are made to employ physical devices for the scientific measurement of some psychological experiences like the sensations of weight, brightness, loudness and other such dimensions. Other complicated psychological phenomena like sleep or span of memory etc. can also be studied by psychophysical methods. Three classical psycho-physical methods devised by the German physiologist and physicist Gustav Fechner (1801-1887) the father of psycho-physics are still in vogue. They are: The method of minimal changes or the method of limits. The method of constant stimuli or the method of right and wrong responses. The method of average or mean error. These methods are primarily employed to measure the absolute threshold and the difference threshold. Both the absolute threshold and the difference threshold are statistical concepts and are measured in much the same way. The absolute threshold may be defined as the minimum value of a physical stimulus that reliably produces sensation. Absolute threshold thus, separates the sounds we can hear from those we cannot, the odours we can smell from those we cannot, the brightness of the light we can see from that we cannot, and so on. The difference threshold may be defined as the minimum difference in value between two stimuli which can be perceived by the subject. For example, when one experiences a particular weight put in one’s hand how much minimum weight has to be added to it a that the total becomes Just distinguishable as different from the first. Let us now give a brief idea of the three psycho-physical method mentioned above.
The Method of Minimal Changes or the Methods of Limits This method may be used for finding out the absolute threshold and difference threshold. The procedure may be outlined as below.
The subject is exposed to a particular sensation. For example, he may be asked to report whether he can see the object lying at a particular distance (say 80 em) or not. He cannot see the distance is gradually decreased until the subject reports that he i:-. able to ‘ee the object Supp05e at the distance of 77 cm he says no but at the distance of 7(1 em he says yes then both these values at which the subject’s response changed from no to yes about the visibility of the object will be noted down by the experimenter. In the next round, the object may be placed at a distance much nearer than the absolute threshold, say 70 em In the present case. This distance may then be gradually faced till the subject reports that he doe not see the object. The successive values at which the subject’s response changes from yes to no is noted down. Let these values be 75 and 76 em in the present case. All these values pertaining to minimal changes 10 the value of the absolute threshold or difference threshold in both descending and ascending series of trials arc then noted down The process is repeated many times. After the completion of seven ascending and descending series the experimenter may compute the average of all these minimal values. (The limits of the intensity of the sensory stimuli which produce a change from 0 to 100 per cent In terms of the feeling OJ’ sensation). In the present example, we may compute the average of the values. 77.
-.1 76 ld’ h I 77 – 76 + 75 76 . 76
4. A minimal value of the distance at which the subject may be able to see the experimental object The absolute threshold Concening auditory Intensity may be similarly determined. In an ascending series of trial, the experimenter, while beginning with a clearly sub-threshold value may progressively raise the internity of the sound until the subject reports that he hears it. In the descending series of trials he may gradually decrease the intensity of sound till the subject reports that he does not hear the sound. The average of all these values, in the several ascending and descending series at which the subject’s response changed about his hearing of the sound is then calculated to be designated as the absolute threshold.
The Method of Constant Stimuli (The Method of Right a nd Wrong Responses) in thIs mdhod the value of the Intensity of the sensory stimulus is not gradually increased or decrca “ed as In the case of the method of limits but the sensory stimulus of varying intenslt) arc presented to the subject at random. The stimuli include at lea t one ample which IS well above the probable threshold value and another sample which IS well belm •• ‘ It. The subject IS then asked to indicate whether or not he detects each or these randomly presented stimuli. The responses of the subject in the form of yes or no are then noted down by the experimenter and ultimately the probability of the yes response is related to intensity of the stimuli. All the values related to the yes responses are then averaged out to give the required threshold.
The Method of Average Error
This method IS als0 called the method of mean error or the adjustment method. In performing experiments by this method the subject is presented with some st1mulus of standard intensity. He may then be asked to adjust a variable stimulus by making a number of attempts In doing 50 he Will probably miss the standard by a certain margin. This 1~ referred to as the error. The average of these errors IS noted down. It is subtracted or added to the standard value (depending upon the positive or negative sign of the value of the computed average error) for giving the subject’s absolute threshold of sensitivity to the stimulus.
Conclusion Regarding Methods
Which of the foregoing methods IS the most useable in studying the problems of educational psychology is a difficult question to answer. All these methods have their own strengths and weaknesses and have some unique characteristics which make them highly specific in particular situations. However, a wise investigator must keep In mind the factor of objectivity, reliability and validity for the solution of the problem in hand. He should posses a keen light into the nature of his subject their problems.