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Science Versus the Stars: A Double-Blind Test of the Validity of the NEOFive-Factor Inventory and Computer-Generated Astrological Natal ChartsAlyssa Jayne Wyman a & Stuart Vyse aa Connecticut CollegePublished online: 07 Aug 2010.

To cite this article: Alyssa Jayne Wyman & Stuart Vyse (2008) Science Versus the Stars: ADouble-Blind Test of the Validity of the NEO Five-Factor Inventory and Computer-GeneratedAstrological Natal Charts, The Journal of General Psychology, 135:3, 287-300, DOI: 10.3200/GENP.135.3.287-300

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The Journal of General Psychology, 2008, 135(3), 287–300Copyright © 2008 Heldref Publications

Science Versus the Stars: A Double-Blind Test of the Validity of the NEO Five-Factor

Inventory and Computer-Generated Astrological Natal Charts

ALYSSA JAYNE WYMANSTUART VYSE

Connecticut College

ABSTRACT. The authors asked 52 college students (38 women, 14 men, M age = 19.3 years, SD = 1.3 years) to identify their personality summaries by using a computer-generated astrological natal chart when presented with 1 true summary and 1 bogus one. Similarly, the authors asked participants to identify their true personality profile from real and bogus summaries that the authors derived from the NEO Five-Factor Inventory (NEO-FFI; P. T. Costa Jr. & R. R. McCrae, 1985). Participants identified their real NEO-FFI profiles at a greater-than-chance level but were unable to identify their real astrological summaries. The authors observed a P. T. Barnum effect in the accuracy ratings of both psychological and astrological measures but did not find differences between the odd-numbered (i.e., favorable) signs and the even-numbered (i.e., unfavorable) signs.

Keywords: astrology, double-blind test, five-factor model, NEO-FFI, personal validation, personality

ASTROLOGERS’ NATAL CHARTS and psychologists’ personality profiles share a common purpose—to provide a description of the respondent’s personal-ity—and they are based on at least two common assumptions. First, astrologers and personality psychologists assume that people possess stable characteristics that, to varying degrees, determine their behavior. This assumption gives person-ality assessment its value. Second, both astrologers and psychologists assume that the instruments they have developed for this purpose can measure these traits. Despite these similarities, astrology and trait psychology represent very differ-ent theories about the causes of personality. Astrologers believe an individual’s character is determined by the arrangement of the planets and stars in relation

Address correspondence to Stuart Vyse, Department of Psychology, Box 5621, Connecticut College, New London, CT 06320, USA; savys@conncoll.edu (e-mail).

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to the moment of that person’s birth. As a result, the natal charts that astrolo-gers construct are designed to identify the relative locations of various celestial objects at the precise time and place of birth. In contrast, many contemporary personality psychologists place the source of personality 9 months earlier—at conception—when the individual’s genetic profile is determined (Brody, 1994). The personality inventories that psychologists use are designed to measure these traits by asking participants to report on their own cognitions and behavior. Groups of specific cognitions and behaviors are thought to be indicative of more general underlying traits.

The similarities between these psychological and astrological personality assessments have led to comparisons of their relative validity. Carlson (1985) tested participants’ ability to recognize their astrological charts and their Califor-nia Personality Inventory (CPI) profiles. Presented with personality descriptions based on their own astrological charts and two other personality descriptions randomly selected from those of others, Carlson’s participants were unable to identify their astrological profiles at greater-than-chance levels. Moreover, using the same procedure, he found that participants were no more skilled at identify-ing their CPI profiles.

A number of factors have been implicated in people’s acceptance of personal-ity feedback, regardless of whether it is psychological or astrological. Taylor and Brown (1988) suggested that many people hold an unrealistically enhanced view of themselves, a characteristic that may make it difficult for them to accurately identify their own personality profiles. If, as Taylor and Brown suggested, this self-enhancing phenomenon were widespread, it would throw into question the usefulness of the personal validation method of Carlson’s (1985) test. Doubts about the accuracy of self-knowledge are further supported by Sundberg’s (1955) study showing that participants were unable to discriminate between their own profiles and bogus profiles derived from the Minnesota Multiphasic Personality Inventory. However, other tests with the CPI have shown that participants can identify their own personality profiles at greater-than-chance levels (Greene, Harris, & Macon, 1979; Word, 1996). Therefore, although personal validation has not yet been successfully demonstrated for astrological charts, a limited number of studies have shown that participants have sufficient self-understanding to discriminate true CPI from bogus CPI (e.g., Word) and 16 Personality Factors (16PF; Hampson, Gilmour, & Harris, 1978) reports.

Several studies have shown that the P. T. Barnum effect (Meehl, 1956), a general tendency for individuals to accept vague and ambiguous descriptions as typical of themselves, influences the acceptance of both astrological (Glick, Got-tesman, & Jolton, 1989) and psychological (Dickson & Kelly, 1985; Forer, 1949; Guastello & Rieke, 1990; O’Dell, 1972; Sundberg, 1955; Word, 1996) personal-ity feedback. Furthermore, there is evidence that, for both kinds of assessment, positive feedback is more readily accepted. For example, in the study by Greene et al. (1979), participants who misidentified their CPI profiles were most likely

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to pick the more positive of the two profiles presented. Other researchers have found similar results (e.g., Collins, Dmitruk, & Ranney, 1977; Glick et al., 1989; Hamilton, 1995). In the case of astrology, the odd-numbered sun signs (i.e., Aries, Gemini, Leo, Libra, Sagittarius, Aquarius) are thought to be more favorable in content than the even-numbered ones (i.e., Taurus, Cancer, Virgo, Scorpio, Cap-ricorn, Aquarius), and some researchers have found a difference in the degree of acceptance of charts for odd sun signs versus even sun signs (Glick et al., 1989; Hamilton, 2001). However, a more recent large-scale study did not replicate this effect (Wunder, 2003). Last, researchers have shown that prior knowledge of an individual’s astrological sun sign is associated with a bias toward acceptance of astrological readings (Hamilton, 1995; Van Rooij, 1994).

We designed the present study as a replication of Carlson’s (1985) study with several substantive modifications. First, in the intervening years, both astrology and personality psychologies have changed. For astrology, recent decades have seen the development of sophisticated computer programs capable of converting birth data into detailed natal charts that include lengthy personality descriptions. In the field of personality, the years since Carlson’s study have included the emer-gence of the Five-Factor Model (FFM), or Big Five, as the dominant trait theory of personality (Costa & McCrae, 1992b; Goldberg, 1993). One of our goals in the present study was to update Carlson’s work by using computer-generated natal charts and the NEO Five-Factor Inventory (NEO-FFI; Costa & McCrae, 1985).

Carlson’s (1985) participants were not able to identify either their astrologi-cal personality descriptions or their CPI profiles given a three-choice task. In other tests with the CPI, participants have successfully identified their own pro-files in two- (Greene et al., 1979) and three-choice (Word, 1996) tasks; however, no studies have reported successful identification of astrological profiles. To maximize the likelihood of correct identification, we used a simple two-choice task. We presented each participant with one real astrological personality descrip-tion and one bogus astrological personality description. Similarly, identifications of the NEO-FFI involved one real profile and one bogus profile. In addition, both to provide more detailed information about participants’ accuracy judgments and to assess the P. T. Barnum effect, sun-sign bias, and odd-even sun-sign effect, we asked participants in the present study to make detailed accuracy ratings of both the astrological charts and the personality test results.

On the basis of previous research indicating that, at least in some instances, participants were able to correctly identify their CPI profiles (Greene et al., 1979; Word, 1996) and the presumed influence of the simpler two-choice arrangement of the present study, we hypothesized that participants would be able to correctly identify their real NEO-FFI profiles. But because no previous study had used a two-choice test with astrological profiles, we were unable to make a hypothesis in this case. We also asked participants to rate the accuracy of all four personality reports (bogus and real astrological charts and NEO-FFI profiles) on a 9-point Likert-type scale ranging from 1 (This is a completely inaccurate description of me)

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to 9 (This is a completely accurate description of me), and on the basis of previous research we hypothesized that participants would give the real NEO-FFI profile significantly higher accuracy ratings than they would the bogus NEO-FFI profile. We did not make a hypothesis regarding the accuracy ratings of the astrologi-cal summaries. In addition, we hypothesized that participants’ ratings of all the profiles, astrological and psychological as well as bogus and real, would be rated somewhat favorably, consistent with the P. T. Barnum effect, and that participants who knew their sun signs would judge their real astrological readings to be more accurate, consistent with the sun-sign bias. Last, due to the conflicting results of prior studies, we made no hypothesis about differences in the accuracy ratings of odd and even signs because of the positive and negative personality descriptions associated with them.

Method

Participants

Participants were 52 Connecticut College students (38 women, 14 men). The ages of the students were between 18 and 22 years (M age = 19.3 years, SD = 1.3 years). We recruited participants from an introductory psychology class and through fliers posted around campus inviting any student to participate in a study of astrology and psychological assessment. There were 14 psychology majors, 28 nonpsychology majors, and 10 participants who were undecided about their major. Students from the introductory psychology class received course credit, and all volunteers received their personalized astrological natal charts as a reward for participation.

Measures

NEO Five-Factor Inventory (NEO-FFI). The NEO-FFI is a 60-item scale derived from the revised NEO Personality Inventory (Costa & McCrae, 1985; 1992a) that measures five facets of personality: Neuroticism (N), Extraversion (E), Open-ness to experience (O), Agreeableness (A), and Conscientiousness (C). Example items include, “I try to be courteous to everyone I meet” (A) and “I like to be where the action is” (E), and all items are rated on a 5-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). The NEO-FFI has shown stable Cronbach’s alphas ranging from .68 to .83 for domains of N, E, and O and alphas from .63 to .79 for A and C domains.

Knowledge and beliefs questionnaire. The only other measure was a brief question-naire that asked for demographic information and assessed knowledge of astrology and belief in the validity of both astrology and psychological personality tests. Two questions asked participants to rate the accuracy of personality descriptions derived from astrological charts and psychological tests on a Likert-type scale ranging

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from 1 (very accurate) to 7 (very inaccurate). Five questions assessed astrological knowledge. The first three asked if the participant knew his or her sun sign and, if so, to name it and list three adjectives associated with people who have the sign. The last two asked participants whether they knew and, if so, to name their ris-ing or ascendant sign and their moon sign. This questionnaire also asked for the participant’s date, location, and time of birth; gender; and major.

Materials

Participants made their assessments on NEO-FFI summary feedback sheets and astrological charts that were modified to allow for accuracy ratings. The NEO-FFI summaries use one of three statements to indicate whether the respon-dent is high, moderate, or low on each of the five traits. For example, the high-N statement is, “sensitive, emotional, and prone to experience feelings that are upsetting” and the low-O statement is, “down to earth, practical, traditional, and pretty much set in your ways.” We modified the feedback sheets to allow partici-pant ratings of the accuracy of each of the five traits, as well as a single global rating of the report as a whole. These ratings were made on a 9-point Likert scale ranging from 1 (This is a completely inaccurate description of me) to 9 (This is a completely accurate description of me).

We generated astrological personality profiles by using Estoric Technolo-gies’ Solar Fire Five v5.0.19 (Dawson & Johnson, 2000) program. Although no conventional reliability or validity data are available for this program, the National Council for Geocosmic Research recommended it for research (National Center for Geocosmic Research, 2004), and it was endorsed by Burk (2001), who said, “Solar Fire continues to be the cutting-edge astrology program avail-able” (p. 342). We edited the natal chart output so that all references to the signs, planets, or houses were gone, to avoid bias due to astrological knowledge. We also removed personality descriptions derived from planetary aspects because astrological charts contain different numbers of aspects and including them would have resulted in real and bogus charts of different lengths. The resulting charts included 29 one- to four-sentence personality descriptions (e.g., “You take pride in your home and family. You like being the center of attention in your home envi-ronment”; “You love spontaneity and new games. You also love new and creative projects, often initiating them yourself”).1 Each of the astrological personality reports included the same 9-point accuracy rating scale used for the NEO-FFI summaries. Using this scale, the participants rated the accuracy of each of the 29 descriptions and, in a separate item, the accuracy of the chart as a whole.

Procedure

Testing occurred in two sessions that were 3 weeks apart. When participants volunteered for this study, we asked them to bring the verified date, time, and

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location of their birth to the first session and encouraged them to contact their parents to obtain accurate birth information. In the first session, we gave partici-pants a packet containing the consent form, NEO-FFI questionnaire, and knowl-edge and beliefs questionnaire, respectively. We instructed participants to fill out the three forms in the order that they were presented. We verbally reminded participants to provide the date, location, and time of their birth and that provid-ing inaccurate information would be a violation of the honor code of the college. After they had completed all forms and returned the packet, we told participants that they would be contacted in approximately two weeks concerning the date of the next session.

During the second session, an experimenter who was blind to the hypothesis and had no knowledge of the real and bogus summaries presented each participant with his or her specific packet containing an instruction sheet and four personal-ity summaries, a real natal chart, a bogus natal chart, a real NEO-FFI summary, and a bogus NEO-FFI summary. We randomly selected the bogus astrological and NEO-FFI summaries from other participants in the study. We randomized the order of the summaries so that each participant had an equal chance of being presented with each summary in each ordinal position. We presented half of the participants with the astrological summaries first and the other half with the NEO-FFI summaries first. Each report was labeled as either “Psychological Report” or “Astrological Report.”

Participants were asked to attend to everything in the packet in the specific order that it was presented, first reading the directions and then rating each state-ment of all four personality summaries on the 9-point scale. In addition, partici-pants provided a single overall accuracy rating for each summary, and we asked them to identify which of the two NEO-FFI reports they believed was their own and which of the two astrological summaries was their own. Last, participants considered all four of the personality reports and identified the one that they thought was the most accurate description of their personality. On completion of all items, participants returned the packet to the experimenter. In return, the experimenter handed each participant a debriefing form and the participant’s real astrological natal chart, which was labeled with the participant’s name on its cover sheet and kept in a separate box from the other experimental materials.

Results

Personal Validation of Personality Descriptions

As we hypothesized, participants were able to correctly identify their NEO-FFI profiles at greater-than-chance levels, χ2(1, N = 52) = 17.31, p < .001 (78.8% correct identifications). In contrast, only 46.2% of participants were able to iden-tify their real astrological summaries, which was not significantly better than the percentage of chance, χ2(1, N = 52) = 0.31, p > .05.

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Accuracy of Personality Reports

Participants rated the accuracy of psychological and astrological personality descriptions in two ways. For each of the five dimensions of the NEO-FFI and each of the 29 personality descriptions of the astrological reports, participants made individual ratings on a 9-point scale. In addition, they assessed the accuracy of each of the four reports in a single overall rating on the same 9-point scale. For the purposes of this analysis, we summed the individual ratings of items on the reports and divided each sum by 5 for the NEO-FFI reports and by 29 for the astrological reports, resulting in mean ratings for each type of report.

To assess the relative accuracy ratings of the four personality reports, we conducted a 2 (gender) × 4 (personality report) mixed-design multivariate analy-sis of variance (MANOVA) with repeated measures across the four personal-ity descriptions and dependent variables being the overall ratings of accuracy and the mean accuracy ratings of the individual personality descriptions. We included gender as an independent variable because previous researchers have shown that women have significantly higher levels of belief in astrology (e.g., Wunder, 2003). In this case, neither the main effect of gender nor the interaction of personality report and gender was significant, but the main effect of personal-ity report was significant, Wilks’s Λ = .489, F(6, 43) = 7.57, p < .001, η2 = .51. Follow-up univariate analyses of variance revealed that there were significant effects of personality report on both overall ratings, F(3, 144) = 7.23, p < .001, η2 = .13, and mean individual item ratings, F(3, 144) = 15.01, p < .001, η2 = .24. The means and standard deviations for the mean-item and overall ratings for each of the four personality summaries are shown in Table 1. Tukey HSD tests revealed

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TABLE 1. Means and Standard Deviations of Accuracy Ratings of Real and Bogus NEO-Five Factor Inventory (NEO-FFI; P. T. Costa, Jr., & R. R. McCrea, 1992a) Summaries and Real and Bogus Astrological Charts (N = 50)

Measure Mean-item ratings Overall ratings

Real NEO-FFI M 7.19 7.23 SD 1.14 1.27Bogus NEO-FFI M 6.21 6.09 SD 1.19 1.53Real astrological M 6.18 6.17 SD 0.91 1.17Bogus astrological M 6.05 6.48 SD 1.16 1.39

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that, for both dependent variables, the real NEO-FFI was rated as significantly more accurate than the other personality reports (p < .05) and that there were no significant differences in accuracy ratings among the other three reports.

Last, when asked to choose which of the four personality reports provided the most accurate description of themselves, 54.9% of participants chose the real NEO-FFI, 19.6% chose the real astrological report, 15.7% chose the bogus astrological report, and only 9.8% chose the bogus NEO-FFI as the most accu-rate personality summary. Participants selected real NEO-FFI significantly more often than they did other summaries, χ2(3, N = 51) = 25.31, p < .001.

P. T. Barnum Effect

The hypothesis that both psychological and astrological assessments would show the P. T. Barnum effect was supported. Each of the four personality reports was submitted to a one-sample t test for which the null hypothesis was that accuracy ratings in Table 1 were not significantly different from 5 (This is right as much as it is wrong). Both for overall ratings and for mean individual item ratings, the t tests revealed that all four personality reports were significantly dif-ferent from this neutral rating. Thus, both bogus NEO-FFI and bogus astrological reports showed evidence of the P. T. Barnum effect.

Sun-Sign Bias and Odd-Numbered Sign Bias

The hypothesis that participants’ prior knowledge of their sun sign would bias them in favor of accepting the astrological descriptions was partially sup-ported. To test this hypothesis, we divided participants into two groups—those who correctly reported their sun sign and those who did not. Then we divided the statements of the real astrological summaries into statements related to the partic-ipant’s sun sign and statements unrelated to the participant’s sun sign. Analysis of these items showed evidence of sun-sign bias. Participants who knew their sun sign gave significantly higher accuracy ratings to the sun-sign-related statements than to the non-sun-sign statements, t(34) = 2.36, p < .05, whereas participants who did not know their sun sign did not, t(15) = 0.12, p > .05. Last, to determine whether the sun-sign bias affected accuracy ratings of the real astrological charts, we conducted a one-way MANOVA across these two groups on the mean-item and overall ratings of the participants’ real astrological charts. There were no significant differences in the accuracy ratings of these two groups, Wilks’s Λ = .996, F(2, 49) = 0.09, p > .05.

To analyze whether there was a bias in favor of the odd-numbered signs (Aries, Gemini, Leo, Libra, Sagittarius, Aquarius), which are often considered more favorable than the even-numbered ones (Taurus, Cancer, Virgo, Scorpio, Capricorn, Aquarius), we grouped participants by odd and even signs and con-ducted a one-way MANOVA across these groups with the overall and mean-item

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accuracy ratings of both the real and bogus astrological charts as the dependent variables. The analysis was not significant, indicating that there was no bias pro-duced by the favorableness of the participant’s sun sign, Wilks’s Λ = .991, F(4, 47) = 0.48, p > .05.

Supplemental Exploratory Analyses

To further examine the results, we performed a number of additional analy-ses. We constructed a correlation matrix to examine the interrelationships of knowledge and belief in astrology, belief in psychological measures, and accu-racy ratings of the various personality measures (see Table 2). Belief in astrology was not correlated with accuracy ratings for either the real or bogus astrological summaries, but participants with greater knowledge of astrology gave the bogus chart a significantly lower total accuracy score. There was no correlation of knowledge or belief with overall ratings of the astrological summaries.

Despite the negative relation between astrological knowledge and accuracy ratings of the bogus astrological profile, a MANOVA revealed that participants who correctly identified their real astrological chart did not differ from those who did not do so in their knowledge of or belief in astrology, Wilks’s Λ = .972, F(2, 49) = 0.71, p > .05. Last, participants who knew their sun signs were less likely to correctly identify their real astrological profiles than those who did not know their sun signs (42% vs. 56%), although a chi-square test showed that this differ-ence was not statistically significant, χ2(1, N = 52) = 0.95, p < .05.

In the case of psychological measures, participants who had greater belief in psychologically based measures gave the bogus NEO-FFI a higher overall rating; however, we did not see this pattern in either the total rating of the bogus NEO-FFI or the mean-item ratings of the real NEO-FFI. Similar to the results with the astrological profile, those who correctly identified their real NEO-FFI results did not differ significantly from those who did not in their degree of belief in psychological measures of personality, t(50) = 0.89, p > .05.

There were a number of positive correlations among the ratings of the real and bogus astrological summaries and the real and bogus NEO-FFI summaries, suggesting that some participants gave consistently higher ratings to all of the reports than others. These correlations were more often seen in the total ratings of the astrological and psychological summaries than in the overall ratings, perhaps because of the presumably greater reliability of the total ratings in comparison with the single item of the overall ratings.

Discussion

Consistent with previous research, we found that participants were unable to identify their own astrological charts at a greater-than-chance level, a result that extended the string of failure using the personal validation technique. Unlike

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Carlson’s (1985) study but consistent with several others (Greene et al., 1979; Hampson et al., 1978; Word, 1996), participants were able to identify their real personality profiles at greater-than-chance levels when these profiles were based on a standardized personality inventory—in this case, the NEO-FFI. Thus, if the unrealistic self-image identified by Taylor and Brown (1988) affected our partici-pants’ ability to identify their astrological profiles, no similar problem affected their identification of the NEO-FFI profiles.

Although Carlson’s (1985) participants were unable to identify their CPI profiles, it is not surprising that in the present study a significant percentage of participants were able to identify their NEO-FFI summaries. First, Carlson used a three-choice test with two bogus CPI reports and one real CPI report, whereas in the present study we used a simple two-choice test involving one real test summary and one bogus test summary. Second, the NEO-FFI contains only five dimensions, all of which are easily understood and well imbedded in the vernacu-lar language of personality description, whereas the CPI contains 18 dimensions, a number of which may be difficult for many people to evaluate.

What is more notable is the inability of participants to identify their real astro-logical profiles at above-chance levels. The use of a two-choice test in the present study was an attempt to maximize the chances of successful identification of both types of personality measures. Although 79% of participants correctly identified their real NEO-FFI report, the present results represent less of an endorsement of psychological measures than a further indictment of astrology. Even in a simple two-choice test, participants failed to identify their own astrological charts at greater-than-chance levels. Like the CPI, the computer-generated astrological reports in the present study contained many more personality descriptors—29 separate personality statements—that may have made the task more difficult than the task with the NEO-FFI.

Still, we tried to use both the psychological and astrological reports in a manner that approximated how they might typically be used. Under these circumstances, participants could not identify their real astrological charts. In addition, the accu-racy ratings of the psychological profiles and astrological reports paralleled the identification results: Participants gave the real NEO-FFI significantly higher ratings than the other profiles. Last, when asked to choose the best description of their personality among all four measures presented, participants chose their real NEO-FFI profile significantly more often than they did the other three.

In the present study, we found evidence of the P. T. Barnum effect in par-ticipants’ evaluations of both the astrological reports and the NEO-FFI profiles. These results are consistent with a number of previous studies (Dickson & Kelly, 1985; Forer, 1949; Glick et al., 1989; Guastello & Rieke, 1990; O’Dell, 1972; Sundberg, 1955; Word, 1996), but the significant result found for the bogus NEO-FFI is noteworthy, because most participants were able to correctly identify their real NEO-FFI profiles. Despite much greater certainty about which NEO-FFI was theirs, participants gave some credence to the bogus profile.

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In the present study, we did find some evidence of sun-sign bias. Participants who knew their sun signs gave more positive ratings to the sun-sign items in their astrological summaries than those who did not. But with all items included (i.e., sun-sign and non-sun-sign items), participants who knew their sun signs did not differ from those who did not in the mean-item accuracy ratings of the real astro-logical chart or in the single global accuracy rating. Thus, the present results are consistent with previous studies finding a sun-sign effect only for those who are knowledgeable about astrology (Hamilton, 1995; Van Rooij, 1994). However, in this case, the bias was restricted to sun-sign-related items and did not extend to the entire astrological profile.

The results of the analysis of the even-numbered positive signs did not reveal a significant difference in participants’ accuracy ratings. Thus, the present results are (a) consistent with the study by Wunder (2003) that failed to find an odd-even sign difference and (b) discrepant with the positive results of Glick et al. (1989) and Hamilton (2001). However, neither the present study nor Wunder’s result contradicts the basic premise that the favorableness of a personality description affects its acceptability because neither study directly measured favorability or unfavorability of the profiles.

Knowledge of astrology was negatively correlated with overall ratings of the bogus astrological chart, presumably because participants who were familiar with the characteristics associated with their sun sign were able to detect them in the real chart and not the bogus one. Surprisingly, this effect of astrological knowledge did not translate into better identification of the real astrological report. Similarly, there was no significant difference in astrological knowledge between those who correctly identified their real astrological profile and those who did not, and those who correctly identified their astrological profile did not differ in their degree of belief in astrology. In the case of the NEO-FFI, belief in the validity of psychologi-cal measures was positively correlated with accuracy rating of the bogus NEO-FFI but not with ratings of the real NEO-FFI. Last, several of the accuracy ratings of both real and bogus NEO-FFI profiles were positively correlated with accuracy rat-ings of the real and bogus astrological profiles, suggesting that participants varied in their overall acceptance of both types of personality information.

The results of the present study reaffirm that, even in a simple two-choice test using computer-generated astrological profiles, participants are unable to dis-tinguish their own astrologically derived personality summaries from those taken at random from other participants. Although there were positive trends, such as the higher ratings of sun-sign descriptions for participants who knew their sun signs and the modest negative correlation between astrological knowledge and the accuracy rating of the bogus astrological profile, participants who had greater belief in or knowledge of astrology were no more likely to correctly identify their astrological profile than those who had greater belief in or knowledge of astrology. In contrast, participants correctly identified their psychologically based NEO-FFI profiles at greater-than-chance levels.

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We note that there was evidence of a P. T. Barnum effect in the accuracy ratings of both the astrological and psychological measures and that belief in psychological measures was positively correlated with the accuracy rating of the bogus NEO-FFI. Thus, although the present results provide some support for the validity of the NEO-FFI and provide no support for the validity of astro-logically derived personality summaries, it appears that both types of measures enjoy somewhat inflated accuracy ratings stemming from participants’ general tendency to see themselves in whatever personality description they are given.

Last, we acknowledge that the personal validation method in this and similar studies provides a rather limited form of validation. Individuals may argue that psychologists or others who know the individual would be better suited to judge whether an astrological profile is an accurate description of the participant. Still, a measure of the profile’s ability to predict future behavior would be more con-vincing. However, because astrological charts are typically shared directly with the person for whom they are constructed, it does not seem unreasonable that the individual be recognizable in the astrological profile.

Furthermore, in the present study, the majority of participants were able to recognize their NEO-FFI profiles, so it is clear that participants’ self-understanding was accurate enough to provide validation for this measure. Possible explanations for the poor results obtained for the astrological profiles include the more complex 29-statement format of the astrological report and a lack of specificity in astrologi-cal descriptions (Hampson et al., 1978). However, for now, personal validation data supporting the validity of astrological personality descriptions are still lacking.

NOTE

1. We based the 29 astrological descriptions on the ascendant sign and 12 house descriptions according to the placement of the ascendant, the sun sign, the house of the sun, the moon sign, the house of the moon, the Mercury sign, the house of Mercury, the Venus sign, the house of Venus, the Mars sign, the house of Mars, the Jupiter sign, the house of Jupiter, the Saturn sign, the house of Saturn, and the houses of Uranus, Neptune, and Pluto. We removed the signs of Uranus, Neptune, and Pluto because they refer to generational descriptions rather than individual personality characteristics.

AUTHOR NOTES

Alyssa Jayne Wyman is an MSW student at Smith College and a 2003 graduate of Connecticut College in New London, Connecticut. Stuart Vyse is professor of psychology at Connecticut College. He specializes in irrational behavior, superstition, and belief in the paranormal.

REFERENCES

Brody, N. (1994). .5 + or – .5: Continuity and change in personal dispositions. In T. F. Heatherton & J. L. Weinberger (Eds.), Can personality change? (pp. 59–81). Washing-ton, DC: American Psychological Association.

Burk, K. (2001). Astrology: Understanding the birth chart: A comprehensive guide to classical interpretation. St. Paul, MN: Llewellyn Worldwide.

Carlson, S. (1985). A double-blind test of astrology. Nature, 318, 419–425.

Wyman & Vyse 299

Dow

nloa

ded

by [

Uni

vers

ity o

f Sy

dney

] at

03:

42 2

0 D

ecem

ber

2013

300 The Journal of General Psychology

Collins, R. W., Dmitruk, V. M., & Ranney, J. T. (1977). Personal validation: Some empirical and ethical considerations. Journal of Consulting and Clinical Psychology, 45, 70–77.

Costa, P. T., Jr., & McCrae, R. R. (1985). The NEO Personality Inventory Manual. Odessa, FL: Psychological Assessment Resources.

Costa, P. T., Jr., & McCrae, R. R. (1992a). NEO PI-R professional manual. Odessa, FL: Psychological Assessment Resources.

Costa, P. T., Jr., & McCrae, R. R. (1992b). Four ways five factors are basic. Personality and Individual Differences, 13, 653–665.

Dawson, G., & Johnson, S. (2000). Solar Fire Five (Version 5.0.19) [Computer software]. Magill, Australia: Esoteric Technologies.

Dickson, D. H., & Kelly, I. W. (1985). The “Barnum effect” in personality assessment. Psychological Reports, 57, 367–382.

Forer, B. R. (1949). The fallacy of personal validation: A classroom demonstration. Jour-nal of Abnormal and Social Psychology, 44, 118–123.

Glick, P., Gottesman, D., & Jolton, J. (1989). The fault is not in the stars: Susceptibil-ity of skeptics and believers in astrology to the Barnum effect. Personality and Social Psychology Bulletin, 15, 572–583.

Goldberg, L. R. (1993). The structure of phenotypic personality traits. American Psycholo-gist, 48(1), 26–34.

Greene, R. L., Harris, M. E., & Macon, R. S. (1979). Another look at personality valida-tion. Journal of Personality Assessment, 43, 419–423.

Guastello, S. J., & Rieke, M. L. (1990). The Barnum effect and validity of computer-based test interpretations: The human resource development report. Psychological Assess-ment, 2, 186–190.

Hamilton, M. (1995). Incorporation of astrology-based personality information into long-term self-concept. Journal of Social Behavior and Personality, 10, 707–718.

Hamilton, M. (2001). Who believes in astrology? Effect of favorableness of astrologically derived personality descriptions on acceptance of astrology. Personality and Individual Differences, 31, 903–914.

Hampson, S. E., Gilmour, R., & Harris, P. L. (1978). Accuracy in self-perception: The “fallacy of personal validation.” British Journal of Social and Clinical Psychology, 17, 231–235.

Meehl, P. E. (1956). Wanted—A good cookbook. American Psychologist, 11, 262–272.National Center for Geocosmic Research. (2004). Research. Retrieved January 27, 2007,

from http://www.geocosmic.org/research/O’Dell, J. W. (1972). P. T. Barnum explores the computer. Journal of Consulting and

Clinical Psychology, 38, 270–273.Sundberg, N. D. (1955). The acceptability of “fake” versus “bona fide” personality test

interpretations. Journal of Abnormal and Social Psychology, 50, 145–147.Taylor, S. E., & Brown, J. D. (1988). Illusion and well being: A social psychological

perspective on mental health. Psychological Bulletin, 103, 193–210. Van Rooij, J. (1994). Introversion-extraversion: Astrology versus psychology. Personality

and Individual Differences, 16, 985–988. Word, S. (1996). Test-taker and close-other selection of personality feedback. Journal of

Personality Assessment, 66, 402–413.Wunder, E. (2003). Self-attribution, sun-sign traits, and the alleged role of favourableness

as a moderator variable: Long-term effect or artefact? Personality and Individual Dif-ferences, 35, 1783–1789.

Manuscript submitted March 4, 2004 Revision accepted for publication February 9, 2006

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