"The Barnum Effect" states that individuals are likely to accept general personality descriptions, this study aims to test this theory and further the research

Hannah Baumer

The difference in acceptance of personality descriptions when known to be randomly selected or thought to be personal horoscopes

Abstract

“The Barnum Effect” states that individuals are likely to accept general personality descriptions, this study aims to test this theory and further the research by testing whether specificity has an effect on the accuracy rating. Participants were split into two groups: the general group and horoscope group, all were given a general personality description, the horoscope group were told these corresponded to their astrological signs and the general group were made aware this was a general description. Both groups rated the descriptions as fairly accurate, supporting “The Barnum Effect” as predicted. Using an independent t-test we analysed the results and found there was no significant difference between the two groups’ ratings and therefore no effect was found through varying the specificity. However this finding may be due to only having two groups, an improvement of the study would be to include more levels of specificity.

Introduction

Personality is an aspect of psychology that forms a key research area, the way in which individuals' thoughts, feelings, and behaviours differ, and the stability of these differences over time is of great interest to psychologists (Pervin & John, 2001). Reliable and valid personality measures have been developed as a requirement to further studies into underlying personality characteristics and the variables that mediate them. One such type of personality assessment is multiple-choice or true/false judgements within tests, allowing the items to be scored objectively (Anastase & Urbina, 1997). An example of such a test would be to present a respondent with a series of statements about their personality and ask them to rate their accuracy.

Early studies examining the acceptance of personality descriptions showed a tendency amongst individuals to believe generalised and ambiguous statements as being true (Forer, 1949). Regardless of the fact that these bogus descriptions could apply to most people, respondents tend to believe them to be uniquely applicable to themselves, this is known as the Barnum Effect, as labelled by Paul Meehl (1956). Forer's (1949) original study involved giving participants a personality test, followed by a personality evaluation, which they were informed would be based on their earlier personality test. All participants then received the same evaluation. Despite this, participants rated the accuracy of the evaluation and a mean of "good" to "excellent" was found. In general, all the acceptance tests have approached the method in a similar way, following the same four steps (a) completing a personality test; (b) waiting while the test is scored; (c) receiving the interpretation; (d) rating the accuracy of the interpretation. Most participants of such tests will receive the same general "Barnum" interpretation (Snyder et al. 1975). There are a number of studies that have since replicated this effect. Furnham (1994) presented participants with vague descriptions about their health, despite being bogus statements, they were again rated as accurate by participants. However not all psychologists believe that the Barnum results hold validity as they cannot be applied to individuals outside of the sample used, as the college students who were chosen as subjects are relatively naive and "unsophisticated" (Dana and Graham 1976). There is further evidence to suggest that acceptance may vary with the "sophistication" of the population, as psychiatric residents were less likely to accept the general personality descriptions than the younger undergraduate and graduate students (Bachrach and Pattishell 1960). The number of residents was so small however, that this finding may lack the validity to be used as a criticism against the Barnum results. In support of the Barnum results, Forer (1949) found no relationship between acceptance and either age or occupational background, and Stagner (1958) found Barnum results to have an equally high level of acceptance from college students, industrial supervisors and personnel managers alike. The Barnum effect may offer at least a partial explanation as to why people continue to believe in astrology (Fichten & Sunerton, 1983). Piper-Terry & Downey (1998) offered women’s’ helpfulness as an explanation as to why female participants concur with their friends’ bogus test interpretations, however Layne argues against this point stating that it women are more open and thus expect their friend’s interpretations to be more accurate. Gullibility of women is also an aspect which psychologists have looked into to explain the Barnum effect, in contradiction to any research into the Barnum effect based on gender Forer (1949), Houston (1976), Snyder & Shenkel (1976) and many others have all reported no differences in the acceptance of personality descriptions by males and females. From this array of supporting research it would appear that both sexes are equally susceptible to the Barnum effect.

Snyder (1974) identified the relevance and specificity of the interpretation to be a further factor in enhancing the Barnum effect. In this study, three groups were presented with the same personality descriptions. One group were told this was a general description, the second group were told the profile was produced using astrological charts from the year and month which they were born, the final group were told the descriptions were based on knowledge of the year, month, and day they were born. Those in the general group rated their descriptions as least accurate, with those in the most specific group ...

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The present study was a partial replica of Synder’s (1974) experiment, this was carried out in order to find whether Synder’s results still hold validity in 2005, as the study was carried out over 30 years ago. The study involved presenting two identical personality profiles to participants in two groups. The first group were told that the descriptions were general; the second group were told the descriptions were based on their personal astrological sign. Both groups were then asked to rate the accuracy of the descriptions compared to their own personalities. It was predicted that both groups would rate the personality profile as at least fairly accurate, demonstrating the Barnum effect, and participants in the horoscope group would rate the accuracy of the profiles as higher than those in the general group, in line with Snyder’s (1974) findings.

Method

Participants

There were 150 participants who took part in the study. The mean age of the group was 20.02, with a range of 18 – 41. There were 127 females and 23 males. The participants were all 1st year undergraduate students studying psychology at Sheffield Hallam University and participated as part of a Research Methods course.

Design

The study was a within participants, correlational design. The independent variable (IV) was the level of specificity related to the descriptions. The dependant variable (DV) was how highly the participants rated the accuracy of the descriptions. Participants were randomly allocated to one of two groups and presented with the same personality descriptions. Due to the nature of this stuffy, a repeated measures design was not suitable so two separate groups were used, ensuring that counterbalancing was not an issue.

Materials/Apparatus

Copies of the same personality description were handed out to all the participants

Procedure

All 150 participants were in a room together where an envelope was handed round containing 75 slips of paper with the number ‘1’ written on them, and a further 75 slips of paper with the number ‘2’ written on them. Those participants that had picked slips of paper with the number ‘2’ on them were asked to leave the room, whilst those with the number ‘1’ on their paper remained in the room. The participants remaining in the room (general group) were each handed a sheet of paper with personality descriptions written on them, and then informed that the descriptions were general and could be true of people generally. After being told to read the profiles they were then asked to rate the accuracy of the description in accordance with their own personalities, and also asked their age and gender. The second group (horoscope group) were then asked to return to the room, whilst the general group left the room. The participants that remained in the room were then told that they were to be presented with personality descriptions from the internet that corresponded with their astrological signs. However, all of the participants from both groups were given the same profiles. Each participant was asked for their personal star sign and handed the appropriate profile. They were then asked to rate the accuracy of the profile according to their own personalities, and asked for their age and gender.

Results

The raw data which was collected from both the general and horoscope groups were accuracy ratings from 1-5 given by the participants to describe the accuracy of the personality descriptions. The majority of participants from the general group gave a rating of 4 for the personality description, the second most popular rating was 3, followed by 5 and then 2, none of the participants gave the description a rating of 1. The horoscope groups’ results were almost the same as the general group, except for a few more ratings of 5 rather than 3. These accuracy ratings were used to obtain the mean, median, mode and standard deviation.

Table 1. Means, medians, modes and standard deviations of the accuracy ratings for the ‘general’ group of participants.

Table 2. Means, medians, modes and standard deviations of the accuracy ratings for the ‘horoscope’ group of participants.

The median and mode within both groups is the same. Although the mean is lower than both the median and mode in both groups, there is not a significant difference between them. The standard deviation is lower in the general group than the horoscope group; again the difference is not substantial.

These histograms have shown that the two groups only differ slightly. Both groups of accuracy ratings are similar, with the majority of participants giving a rating of 4 in both groups.

The accuracy rating of the personality descriptions was analysed using an independent t-test. This showed no significance in the ratings between the two groups (t (148) = -1.87, p=0.62)

Discussion

The results showed that there was no significant difference between the two experimental groups. The hypothesis is partially supported as both groups rated the personality descriptions as fairly high, thus supporting the Barnum effect, however there was no significance between the two groups’ ratings and so the second part of our hypothesis must be rejected as we cannot rely on an insignificant difference.

Although the findings show that a higher level of specificity does result in higher accuracy ratings, the difference is not significant enough for these findings to support Snyder’s (1974) research that specificity increases accuracy ratings. As our research was not as specific as Snyder’s experiment, this may explain why our ratings did not show significance, rather than presuming that there were issues which could have been resolved within Snyder’s theory.

One of the problems with the current study is that we only used two groups, rather than Snyder’s method of looking at three levels of specificity, perhaps resulting in our inability to find any significance between the groups. Another problem with the study is that all the participants were Psychology students, as Dana and Graham (1976) suggested; students may be relatively naïve and “unsophisticated”, preventing the findings from being applied to individuals outside of the sample.

One way that we might further this research is to look into any differences between the acceptance of personality descriptions between males and females; it may be that females are more likely to accept horoscopes than males. We could also look into the significance of using a friend to present personality descriptions to individuals, as Downey (1998) suggested females are more likely to accept their friend’s bogus interpretations as a result of their ‘helpfulness’.

In conclusion, this study has shown that individuals are likely to accept general personality descriptions and rate their accuracy highly, supporting the Barnum effect, however the levels of specificity did not have a significant effect on the accuracy ratings, this may be due to a methodological issue in which we did not use enough specificity groups.

References

Snyder, C. R., Shenkel, R. J., & Lowery, C. R. (1977). Acceptance of Personality Interpretations: The “Barnum Effect” and Beyond. Journal of Consulting and Clinical Psychology, Vol. 45, 1, 104-114.

Bachrach, A. J., & Pattishell, E. G. (1960) An experiment in universal and personal validation. Psychiatry, 23, 267-270.

Dana, R. H., & Graham, E. D. (1976). Feedback of client-relevant information and clinical practice. Journal of personality Assessment, 40, 464-469.

Forer, B. R. (1949). The fallacy of personal validation: A classroom demonstration of gullibility. Journal of abnormal and social psychology, 44, 118-123.

Meehl, P. E. (1956). Wanted – A good cookbook. American Psychologist, 11, 262-272.

Stagner, R. (1958) The gullibility of personnel managers. Personnel Psychol., 11, 347-352.

Gauquelin, M. (1969) The scientific Basis of Astrology. New York: Stein & Day.

Snyder, C. R., (1974) Why horoscopes are true: The effects of specificity on acceptance of astrological interpretations. Journal of clinical Psychology, 30, 577-580.

Anastase, A. & Urbina, S. (1997) Psychological Testing (7th Ed.). Prentice Hall.

Pervin, L.A. & John, O.P. (2001) Personality Theory and Research. New York: Wiley.

Furnham, A. and Schofield, S. (1978). Accepting Personality Test Feedback: A Review of the Barnum Effect, Current Psychological Research & Reviews, 6, 2, 162-178.

Fichten, C.S. & Sunerton, B. (1983). Popular horoscopes and the “Barnum Effect”, Journal of Psychology, 114, 123-134.