Thigpen & Cleckley’s study was intended to describe a case study of a woman (‘Eve White’) whom the psychologists diagnosed with multiple-personality-disorder. The study presents evidence for the existence of this previously rare condition. Thigpen & Cleckley used a combination of both qualitative and quantitative data in order to provide support for their diagnosis and the existence of MPD. Eve White was believed to have two other personalities – Eve Black and Jane. The qualitative data obtained by the psychologists included observations of distinctions in character, attitudes, behaviour and mannerisms between Eve Black and Eve White, obtained through over 100 hours of interviews. Quantitative data was obtained from a variety of sources. One source was independent psychological testing which included psychometric testing in which Eve White was found to have better memory function and an IQ of 110 compared to Eve Black’s IQ of 104. Projective testing was also used. Further quantitative data, which showed differences between the personalities, was obtained through EEG Testing (electroencephalograph) and micro strabismus tests. This evidence provided the first strong support for the existence of MPD.
In Rosenham’s study mainly qualitative data was obtained. Rosenham wanted to show the poor reliability of the diagnostic system for mental disorders. Data to support this was that all 8 pseudo-patients were admitted to mental hospitals, with the diagnosis of schizophrenia in seven cases, and the lengths of stay ranged from 7 to 52 days. Also seven of the patients were released with ‘schizophrenia in remission’. This suggests that they were never detected as being sane. Rosenham also wanted to show the negative effects of being diagnosed as abnormal. To show this observations were made by the pseudo-patients about how they were treated. All data they recorded was qualitative. Observations included a lack of monitoring, distortion of behaviour (e.g. ‘patient engages in writing behaviour’), a lack of normal interaction and also powerlessness and depersonalisation.
(ii) Using quantitative data to describe human behaviour has many strengths and weaknesses. A strength of quantitative data is that it is more objective rather than subjective so it could be considered to have more validity, e.g. in Gould’s Study the principal of testing intelligence rather than interpreting it is a more reliable measurement. Another advantage of quantitative data is that its validity can be tested statistically e.g. Hraba & Grant tested the significance of their data using chi-square. A further advantage of using qualitative data is that it can be used to provide support for interpretations of behaviour e.g. Thigpen & Cleckley used quantitative data obtained from psychometric and psychological testing to support their diagnosis of MPD. Quantitative data also has the advantage that it can be presented in a graphical display, which may make the data easier to understand e.g. pie charts used by Hraba & Grant. A final advantage is that it is usually easier to replicate studies if the data they obtained was quantitative.
A weakness of quantitative data is that it is sometimes reductionist. For instance quantitative data could be considered too simplistic when considering something as complex as human behaviour e.g. Hraba & Grant uses doll choice to represent racial preference and awareness and tally the choices of doll, but this may not truly represent racial preferences. Another weakness of using quantitative data to describe behaviour is that data may be statistically significant but not humanly significant, behaviour is a vast area of psychology, which cannot be accounted for by using only numbers. A final weakness is that narrow unrealistic information may be obtained that only relates to a tiny portion of the concept of behaviour e.g. Yerkes IQ test only related to a tiny area of knowledge (mainly knowledge of American culture) and ignored the wide range and variety of intelligence humans have.
(iii) Many of the studies considered above could have been improved by using a mixture of both the qualitative and quantitative approaches. I believe that Yerkes’ IQ test could have benefited greatly improved by the addition of a qualitative analysis of each soldier based on each officer’s abilities in communication etc. I also believe that the Yerkes’ IQ test could have been improved by using a wider variety of questions. He could have asked many people from around the world to write a brief report about what they consider necessary in producing a fair and reliable method of IQ testing. This qualitative data could then have aided Yerkes in producing a more valid IQ test, suitable for people of all cultures.
I believe Hraba & Grant’s study also could have benefited from combining qualitative data with the quantitative data they obtained. Although their findings provided evidence of how societies attitudes affect racial preference and identification, they only tackled a small area of the larger issue. I believe it would have been better to get opinions about racial preference and identification from various adults from society through interviews and then use the doll experiment with children to add validity to their findings.
In Zimbardo’s prison simulation all the data collected and was qualitative. All the conclusions and observations made were down to subjective interpretations by the observers so the validity of the results can be questioned. To provide support for his theories and observations Zimbardo could have obtained some quantitative data about the guards and prisoners to provide evidence for their behaviour change. For example he could have measured the blood pressure of each subject before and after the experiment. Alternatively he could have asked each subject to fill in a questionnaire to rate how strongly they felt different emotions before and after the experiment (e.g. on a scale of 1 to 10 how happy/ excited do you feel?).
Rosenham too collected mostly qualitative data from observations made by the pseudo-patients (of which Rosenham was one) once admitted to the mental hospitals. One of the main problems of having the pseudo-patients making observations is that they may be subjective rather than objective so the validity is lower. Also Rosenham’s observations are clearly unreliable as he is open to experimenter bias and may make exaggerated observations to support his theories. In order to improve the experiment Rosenham and the other pseudo-patients could have collected some quantitative data when in the hospital. For instance they could have recorded the number of times they asked a member of the hospital staff a question and the number of times they were ignored.
I believe the most valid way to conduct a psychological study is to use a combination of the quantitative and qualitative approaches. When tackling a complex issue, such as human behaviour, it is reductionist to account for such a vast issue with a few numbers. A better approach is to use interviews and questionnaires to gather as much knowledge on the subject as possible. This can then be used to make detailed theories and conclusions about the subject, in this case human behaviour. Once the theories have been made they can then be given validity by obtaining quantitative data to support them. This can be seen in the study by Thigpen & Cleckley. They treat Eve White through interviews and careful analysis in order to conclude what the wrong with her. They then seek to provide support for their conclusions by obtaining quantitative data by using a series of psychological, psychometric and EEG tests.
