Revised NEO Personality Inventory
This article has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)(Learn how and when to remove this template message)
The Revised NEO Personality Inventory (NEO PI-R) is a personality inventory, published in 1990 and keyed the Big Five personality traits. It is a revised version of Costa and McCrae’s (1978) NEO Personality Inventory. The NEO PI-R consists of 240 items. A shortened version, the NEO Five-Factor Inventory (NEO-FFI), comprises 60 items (12 items per domain). Both the NEO PI-R and NEO-FFI have been updated over the years, with their last updates in 2010. While the NEO PI-R is still published, the NEO Personality Inventory-3 (NEO PI-3) is the 2010 revision of the NEO PI-R. The NEO Five-Factor Inventory-3 (NEO-FFI-3) is the 2010 revision of the NEO-FFI. The revised inventories feature updated norms.
The NEO PI-R assesses the Big Five personality traits: Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness to Experience. Additionally, the inventory assesses six subordinate dimensions (known as facets) of each of the main personality factors. The test was developed by Paul Costa, Jr. and Robert McCrae for use with adult men and women without overt psychopathology. It was later shown to also be useful at younger ages.
A table of the personality dimensions measured by the NEO PI-R, including facets, is as follows:
|Neuroticism||Extraversion||Openness to experience||Agreeableness||Conscientiousness|
|Vulnerability to Stress||Positive Emotion||Values||Tendermindedness||Deliberation|
In the 1970s, Paul Costa and Robert McCrae were researching age-related changes in personality. Costa and McCrae reported that they began by looking for the broad and agreed-upon traits of Neuroticism (N) and Extraversion (E), but cluster analyses led them to a third broad trait, Openness to Experience (O). The original version of the inventory, which was published in 1978, included only those three factors. The inventory was then called the Neuroticism-Extraversion-Openness Inventory (NEO-I). This version would be included in the Augmented Baltimore Longitudinal Study of Aging.
Based on data from the Baltimore study, Costa and McCrae recognized two additional factors: Agreeableness (A) and Conscientiousness (C). Accordingly, in 1985 they published the first manual for the NEO that included all five factors, which are now known as the Big Five personality personality traits. Costa and McCrae renamed their instrument the NEO Personality Inventory (NEO PI). In this version, "NEO" was now considered part of the name of the test and was no longer an acronym. The assessment at this time included six facet sub-scales for the three original factors (N, E, & O). This naming convention continued with the third version, with the Revised NEO Personality Inventory, published in 1990, being referred to as NEO PI-R.
Research began to accumulate that indicated that the five factors were sufficiently broad and useful. There were also calls for a more detailed view of personality. In 1992 Costa and McCrae published a Revised NEO manual which included six facets for each factor (30 in total).
In the mid- to late-1990s, Costa and McCrae came to understand that some items on the NEO PI-R were outdated or too difficult for many test-takers to understand. Research also began to show that the NEO PI-R had the potential to be used with adolescents and children as young as 10. The possibility of using the NEO with young people led Costa and McCrae in 2002 to administer the NEO PI-R to over 1,900 high school students. The research identified 48 "problem" items that reflected either participant difficulties with item wording and/or low corrected item total correlations (CITCs). Alternative items were developed to replace the "problem" items; the revised instrument was administered to new samples The NEO PI-R and a revised version of the instrument were administered to 500 adolescents, 635 adults, and 449 middle school age children (12-13 year old). For both the adolescent and adult sample, the item/facet correlations were higher for the revised version of the NEO than for NEO PI-R. In addition, the internal consistency, factor structure, and tests of convergent and discriminant validity suggested that the revised version could be used with middle school children. Of the original 48 "problem" items, 37 were improved in terms of clarity and/or CITC. In 2005, Costa and McCrae published the latest version of the NEO Inventories, NEO PI-3. The new version included revisions of 37 items. With the creation of the NEO PI-3, Costa and McCrae intended to make the inventory accessible to a wider portion of the population. The improved readability of the NEO PI-3 compared to the NEO PI-R allowed the newer measure to be used with younger populations and adults with lower educational levels. Additionally, with the replacement of the 37 items, the psychometric properties of the NEO PI-3 were slightly improved over the NEO PI-R. In addition to increasing the readability of the NEO PI, the NEO PI-3 added a glossary of less familiar terms to aid in administration.
Forms and administration
In the most recent publication, there are two forms for the NEO, self-report (form S) and observer-report (form R) versions. Both forms consist of 240 items (descriptions of behavior) answered on a five-point Likert scale. Finally, there is a 60-item inventory, the NEO FFI. There are paper and computer versions of both forms.
The manual reports that administration of the full version should take between 30 and 40 minutes. Costa and McCrae reported that an individual should not be evaluated if more than 40 items are missing. They also state that despite the fact that the assessment is "balanced" to control for the effects of acquiescence and nay-saying, that if more than 150 responses, or fewer than 50 responses, are "agree" or "strongly agree," the results should be interpreted with caution.
Scores can be reported to most test-takers on "Your NEO Summary," which provides a brief explanation of the assessment, and gives the individuals domain levels and a strengths-based description of three levels (high, medium, and low) in each domain. For example, low N reads "Secure, hardy, and generally relaxed even under stressful conditions," whereas high N reads "Sensitive, emotional, and prone to experience feelings that are upsetting." For profile interpretation, facet and domain scores are reported in T scores and are recorded visually as compared to the appropriate norming group.
The internal consistency of the NEO scales was assessed on 1,539 individuals. The internal consistency of the NEO PI-R was high, at: N = .92, E = .89, O = .87, A = .86, C = .90. The internal consistency of the facet scales ranged from .56 to .81. The internal consistency of the NEO PI-3 was consistent with that of the NEO PI-R, with α ranging from .89 to .93 for the five domains. Internal consistency coefficient from the facets, with each facet scale comprising fewer items than each of the Big Five scales, were necessarily smaller, ranging from .54 to .83.
For the NEO FFI (the 60 item domain only version) the internal consistencies reported in the manual were: N = .79, E = .79, O = .80, A = .75, C = .83. In the literature, the NEO FFI is used more often, with investigators using the NEO PI-R usually using the items from just the domains they are interested in. Sherry et al. (2007) found internal consistencies for the FFI to be as follows: N = .85, E = .80, O = .68, A = .75, C = .83.
The NEO has been translated into many languages. The internal consistency coefficients of the domain scores of a translation of the NEO that has been used in the Philippines are satisfactory. The alphas for the domain scores range from .78 to .90, with facet alphas having a median of .61. Observer-ratings NEO PI-R data from 49 different cultures was used as criterion in a recent study which tested whether individuals’ perceptions of the "national character" of a culture accurately reflected the personality of the members of that culture (it did not).
The test-retest reliability of the NEO PI-R has also been found to be satisfactory. The test-retest reliability of an early version of the NEO after 3 months was: N = .87, E = .91, O = .86. The test-retest reliability for over 6 years, as reported in the NEO PI-R manual, was the following: N = .83, E = .82, O = .83, A = .63, C = .79. Costa and McCrae pointed out that these findings not only demonstrate good reliability of the domain scores, but also their stability (among individuals over the age of 30). Scores measured six years apart varied only marginally more than scores measured a few months apart.
The psychometric properties of NEO PI-R scales have been found to generalize across ages, cultures, and methods of measurement.
Effect of age
Although individual differences (rank-order) tend to be relatively stable in adulthood, there are maturational changes in personality that are common to most people (mean-level changes). Most cross-sectional and longitudinal studies suggest that neuroticism, extraversion, and openness tend to decline, whereas agreeableness and conscientiousness tend to increase during adulthood. A meta-analysis of 92 personality studies that used several different inventories (among them NEO PI-R) found that social dominance, conscientiousness, and emotional stability increased with age, especially in the age span of 20 to 40.
Costa and McCrae reported in the NEO manual research findings regarding the convergent and discriminant validity of the inventory. Examples of these findings include the following:
- For the Myers-Briggs Type Indicator, Introversion is correlated with the NEO facet Warmth at −0.61, and with the NEO facet Gregariousness at −0.59. Intuition is correlated with the NEO facet Fantasy at 0.43 and with the NEO facet Aesthetics at 0.56. Feeling is correlated with the NEO facet Tender-mindedness at 0.39.
- For the Self-Directed Search (a personality inventory developed by John L. Holland for careers work), Artistic is correlated with the NEO facet Aesthetic at 0.56, Investigative is correlated with the NEO facet Ideas at 0.43, and Social is correlated with the NEO facet Tender-mindedness at 0.36.
A number of studies evaluated the criterion validity of the NEO. For example, Conard (2005) found that Conscientiousness significantly predicted the GPA of college students, over and above using SAT scores alone. In a study conducted in Seville, Spain, Cano-Garcia and his colleagues (2005) found that, using a Spanish version of the inventory, dimensions of the NEO correlated with teacher burnout. Neuroticism was related to the "emotional exhaustion" dimension of burnout, and Agreeableness, with the "personal accomplishment" burnout dimension. Finally, Korukonda (2007) found that Neuroticism was positively related to computer anxiety; Openness and Agreeableness were negatively related to computer anxiety.
Critical reviews of the NEO PI-R were published in the 12th edition of the Mental Measurements Yearbook (MMY), a source that includes critiques of a large number of psychological tests and scales. Widiger praised the NEO PI-R for its having been developed with the help of factor analyses. He, however, criticized the NEO for not controlling for social desirability bias. He argued that test developers cannot assume participants will be honest, especially in settings where it benefits people to present themselves in a better light (e.g., forensic or personnel settings). Ben-Porath and Waller pointed out that the NEO Inventories could be improved with the addition of controls for dishonesty and social desirability.
Juni, in another review of the NEO PI-R for the MMY, praised the NEO PI-R for including both self- and other-report scales, making it easier for psychologists to corroborate information provided by a client or research participant. However, Juni criticized the NEO PI-R for its conceptualization using the Five Factor Model (FFM) of personality. Juni argued that the existence of the FFM was phenomenological and atheoretical, the model gaining popularity as a result of the influence of the authors (McCrae and Costa) in the psychological community. The NEO PI-R has also been criticized because of its market-oriented, proprietary nature. In response to the expense involved in using proprietary personality inventories such as the NEO, other researchers have contributed to the development of the International Personality Item Pool (IPIP); IPIP items and scales are available free of charge.
A shortened version of NEO PI-R has been published. The shortened version is the NEO Five-Factor Inventory (NEO-FFI). It comprises 60 items and is designed to take 10 to 15 minutes to complete; by contrast, the NEO PI-R takes 45 to 60 minutes to complete. The NEO-FFI was revised in 2004. With the publication of the NEO PI-3 in 2005, a revised version of the NEO-FFI was also published. The revision of the NEO-FFI involved the replacement of 15 of the 60 items. The revised edition is thought to be more suitable for younger individuals. The new version had a stronger factor structure and increased reliability.
Additionally, an even shorter measure of personality has been developed. It is called the Ten Item Personality Inventory (TIPI). It too assesses the Big Five personality traits. The TIPI can be used in situations in which time is limited. The scale is psychometrically inferior to longer, multiple-item scales. The TIPI, however, has a number of strengths. First, it has acceptable correlations with more widely used Big Five measures. Second, the TIPI has adequate test-retest reliability. Third, its correlations with criterion variables are similar to the correlations found in research with longer Big-Five measures. The TIPI may, thus, be useful in situations where very brief measures of personality are needed.
Evidence of the NEO scales' stability in different countries and cultures can be considered evidence of its validity. A great deal of cross-cultural research has been carried out on the Five-Factor Model of Personality. Much of the research has relied on the NEO PI-R and the shorter NEO-FFI. McCrae and Allik (2002) edited a book consisting of papers bearing on cross-cultural research on the FFM. Research from China, Estonia, Finland, the Philippines, France, German-speaking countries, India, Portugal, Russia, South Korean, Turkey, Vietnam, and Zimbabwe have shown the FFM to be robust across cultures.
Rolland, on the basis of the data from a number of countries, asserted that the neuroticism, openness, and conscientiousness dimensions are cross-culturally valid. Rolland further advanced the view that the extraversion and agreeableness dimensions are more sensitive to cultural context. Age differences in the five-factors of personality across the adult life span are parallel in samples from Germany, Italy, Portugal, Croatia, and South Korea. Data examined from many different countries have shown that the age and gender differences in those countries resembled differences found in U.S. samples. An intercultural factor analysis yielded a close approximation to the five-factor model.
McCrae, Terracciano et al. (2005) further reported data from 51 cultures. Their findings were consistent with idea of the rough equivalence of NEO PI-R five factors and facets across cultures. They suggested that aggregate personality profiles provide insight into cultural differences.
With the recent development of the NEO PI-3, cross-cultural research will likely begin to compare the newer version with the NEO PI-R. Piedmont and Braganza (2015) compared the NEO PI-R to the NEO PI-3 using an adult sample from India. They used an English version of the NEO PI-3 in order to measure its utility in individuals who speak English as a second language. Piedmont and Braganza found that the NEO PI-3 had slightly higher item/total correlations and better test-retest reliability than the NEO PI-R. They suggested that the NEO PI-3 has the potential to be utilized with those who do not speak English as their first language.
Brain and genetics
The NEO PI-R has been used in research pertaining to both (a) genotype and personality and (b) brain and personality. Such studies, however, have not always been conclusive. For example, one study found some evidence for an association between NEO PI-R facets and polymorphism in the tyrosine hydroxylase gene, while another study could not confirm the finding.
In a study published in Science, Lesch et al. (1996) found a relationship between the serotonin transporter gene regulatory region (5-HTTLPR) and the neuroticism subscale. Individuals with a shorter allele had higher neuroticism scores than individuals with the longer allele. The effect was significant for heterozygotes and even stronger for people homozygous for the shorter allele. Although the finding is important, this specific gene contributes to only 4% of the phenotypic variation in neuroticism. The authors concluded that "if other genes were hypothesized to contribute similar gene dosage effects to anxiety, approximately 10 to 15 genes might be predicted to be involved."
- Psychological testing
- Minnesota Multiphasic Personality Inventory
- 16PF Questionnaire
- Synthetic Aperture Personality Assessment
- Costa, P. T.; McCrae, R. R. (1976). "Age differences in personality structure: A cluster analytic approach". Journal of Gerontology. 31 (5): 564–570. doi:10.1093/geronj/31.5.564. PMID 950450.
- Shock, Nathan W.; Greulich, Richard C.; Costa, Paul T.; Andres, Reubin; Lakatta, Edward G.; Arenberg, David; Tobin, Jordan D. (1984). "Normal human aging: The Baltimore longitudinal study of aging" (PDF). Bethesda, MD: National Institute of Health.
- Costa, Paul T.; McCrae, Robert R. (1985). "The NEO personality inventory manual". Odessa, FL: Psychological Assessment Resources.
- Briggs, S. R. (1989). Buss, D. M.; Cantor, N., eds. The optimal level of measurement for personality constructs. Personality psychology: Recent trends and emerging directions. NY: Springer-Verlag. pp. 246–260.
- Costa, P. T., Jr., & McCrae, R. R. (1992). NEO PI-R professional manual. Odessa, FL: Psychological Assessment Resources, Inc.
- McCrae R. R.; Costa P. T.; Martin T. A. (2005). "The NEO PI-3: A more readable revised NEO personality inventory". Journal of Personality Assessment. 84 (3): 261–270. doi:10.1207/s15327752jpa8403_05. PMID 15907162.
- McCrae, R. R., & Costa, P. T., Jr., (2010). NEO Inventories: Professional manual. Lutz, FL: Psychological Assessment Resources, Inc.
- McCrae, Robert R.; Martin, Thomas A.; Costa, Paul T. (2005-12-01). "Age Trends and Age Norms for the NEO Personality Inventory-3 in Adolescents and Adults". Assessment. 12 (4): 363–373. doi:10.1177/1073191105279724. ISSN 1073-1911. PMID 16244117.
- Sherry, S. B.; Hewitt, P. L.; Flett, G. L.; Lee-Baggley, D. L.; Hall, P. A. (2007). "Trait perfectionism and perfectionistic self-presentation in personality pathology". Personality and Individual Differences. 42 (3): 477–490. doi:10.1016/j.paid.2006.07.026.
- Church, A. T.; Katigbak, M. S. (2002). "Indigenization of psychology in the Philippines". International Journal of Psychology. 37 (3): 129–148. doi:10.1080/00207590143000315.
- Katigbak, M. S.; Church, A. T.; Guanzon-Lapeña, M. A.; Carlota, A. J.; Del, G. H. (2002). "Are indigenous personality dimensions culture specific? Philippine inventories and the five-factor model". Journal of Personality and Social Psychology. 82 (1): 89–101. doi:10.1037/0022-35126.96.36.199. PMID 11811638.
- Terracciano, A.; Abdel-Khalek, A. M.; Adám, N.; Adamovová, L.; Ahn, CK; Ahn, HN; Alansari, BM; Alcalay, L; Allik, J; Angleitner, A; Avia, MD; Ayearst, LE; Barbaranelli, C; Beer, A; Borg-Cunen, MA; Bratko, D; Brunner-Sciarra, M; Budzinski, L; Camart, N; Dahourou, D; De Fruyt, F; De Lima, MP; Del Pilar, GE; Diener, E; Falzon, R; Fernando, K; Ficková, E; Fischer, R; Flores-Mendoza, C; Ghayur, MA (2005). "National Character Does Not Reflect Mean Personality Trait Levels in 49 Cultures". Science. 310 (5745): 96–100. doi:10.1126/science.1117199. PMC . PMID 16210536.
- McCrae, R. R.; Costa, P. T. (1983). "Joint factors in self-reports and ratings: Neuroticism, extraversion and openness to experience". Personality and Individual Differences. 4 (3): 245–255. doi:10.1016/0191-8869(83)90146-0.
- McCrae R. R.; Kurtz J. E.; Yamagata S.; Terracciano A. (2011). "Internal consistency, retest reliability, and their implications for personality scale validity". Pers Soc Psychol Rev. 15 (1): 28–50. doi:10.1177/1088868310366253. PMC . PMID 20435807.
- Paul T. Costa, Jr. & Robert R. McCrae (2006). "Age Changes in Personality and Their Origins: Comment on Roberts, Walton, and Viechtbauer (2006)" (PDF). Psychological Bulletin. 132 (1): 26–28. doi:10.1037/0033-2909.132.1.26. PMID 16435955.
- Brent W. Roberts; Kate E. Walton; Wolfgang Viechtbauer (January 2006). "Patterns of Mean-Level Change in Personality Traits Across the Life Course: A Meta-Analysis of Longitudinal Studies" (PDF). Psychological Bulletin. 132 (1): 1–25. doi:10.1037/0033-2909.132.1.1. PMID 16435954.
- Conard, M. A. (2006). "Aptitude is not enough: How personality and behavior predict academic performance". Journal of Research in Personality. 40 (3): 339–346. doi:10.1016/j.jrp.2004.10.003.
- Francisco Javier Cano-García, Eva Maria Padilla-Muñoz & Miguel Ángel Carrasco-Ortiz (2005). "Personality and contextual variables in teacher burnout" (PDF). Personality and Individual Differences. 38 (4): 929–940. doi:10.1016/j.paid.2004.06.018.
- Appa Rao Korukonda (2007). "Differences that do matter: A dialectic analysis of individual characteristics and personality dimensions contributing to computer anxiety". Computers in Human Behavior. 23 (4): 1921–1942. doi:10.1016/j.chb.2006.02.003.
- Widiger, Thomas A. (1995). Conoley, Jane Close; Impara, James C., eds. Review of the Revised NEO Personality Inventory. The Twelfth Mental Measurements Yearbook. Lincoln, NE: Buros Institute of Mental Measurements. ISBN 0-910674-40-X. Retrieved from Mental Measurements Yearbook database.
- Ben-Porath Y. S.; Waller N. G. (1992). "Five big issues in clinical personality assessment: A rejoinder to Costa and McCrae". Psychological Assessment. 4 (1): 23–25. doi:10.1037/1040-35188.8.131.52.
- Juni, S. (1995). Conoley, Jane Close; Impara, James C., eds. Review of the Revised NEO Personality Inventory. The Twelfth Mental Measurements Yearbook. Lincoln, NE: Buros Institute of Mental Measurements. ISBN 0-910674-40-X.
- Murphy Paul, A. (2004). The cult of personality: How personality tests are leading us to miseducate our children, mismanage our companies, and misunderstand ourselves. New York: Simon and Schuster.
- Mccrae, R. R., & Costa, P. T. (February 2004). "A contemplated revision of the NEO Five-Factor Inventory". Personality and Individual Differences. 36 (3): 587–596. doi:10.1016/S0191-8869(03)00118-1.
- Gosling, S. D., Rentfrow, P. J., & Swann, W. B. (June 2003). "A very brief measure of the Big-Five personality domains". Journal of Research in Personality. 37 (6): 504–528. doi:10.1016/S0092-6566(03)00046-1.
- McCrae, R. R. & Allik, J. (Eds.) (2002), The Five-Factor model of personality across cultures. N.Y.: Kluwer Academic Publisher.
- McCrae, R. R.; Costa, P. T.; Yik, M. S. M. (1996). Bond, M. H., ed. Universal aspects of Chinese personality structure. The handbook of Chinese psychology. Hong Kong: Oxford University Press.
- Yik, M. S. M.; Bond, M. H. (1993). "Exploring the dimensions of Chinese person perception with indigenous and imported constructs: Creating a culturally balanced scale". International Journal of Psychology. 28: 75–95. doi:10.1080/00207599308246919.
- Pulver, A.; Allik, J.; Pulkkinen, L.; Hämäläinen, M. (1995). "The Big Five Personality Inventory in two non-Indo-European languages". European Journal of Personality. 9 (2): 109–124. doi:10.1002/per.2410090205.
- McCrae, R. R.; Costa, P. T. Jr.; Del Pilar, G. H.; Rolland, J. P.; Parker, W. D. (1998). "Cross-cultural assessment of the five-factor model: The revised NEO Personality Inventory". Journal of Cross-Cultural Psychology. 29: 171–188. doi:10.1177/0022022198291009.
- Angleitner, A.; Ostendorf, F. (July 2000). "The FFM: A comparison of German speaking countries (Austria, Former East and West Germany, and Switzerland)". Paper presented at the XXVIIth International Congress of Psychology, Stockholm, Sweden
- Lodhi, P. H.; Deo, S.; Belhekar, V. M. (2002). McCrae, R. R.; Allik, J., eds. The Five-Factor model of personality in Indian context: measurement and correlates. The Five-Factor model of personality across cultures. NY: Kluwer Academic Publisher. pp. 227–248.
- Lima, M. P. (2002). McCrae, R. R.; Allik, J., eds. Personality and culture: The Portuguese case. The Five-Factor model of personality across cultures. NY: Kluwer Academic Publisher. pp. 249–260.
- Martin, T. A.; Oryol, V. E.; Rukavishnikov, A. A.; Senin, I. G. (July 2000). "Applications of the Russian NEO PI-R". Paper presented at the XXVIIth International Congress of Psychology, Stockholm, Sweden.
- Piedmont, R. L.; Chae, J. H. (1997). "Cross-cultural generalizability of the five-factor model of personality: Development and validation of the NEO PI-R for Koreans". Journal of Cross-Cultural Psychology. 28 (2): 131–155. doi:10.1177/0022022197282001.
- Gülgöz (2002). McCrae, R. R.; Allik, J., eds. Five-Factor Model and NEO PI-R in Turkey. The Five-Factor model of personality across cultures. NY: Kluwer Academic Publisher. pp. 175–196.
- Leininger, A. (2002). McCrae, R. R.; Allik, J., eds. Vietnamese American personality and acculturation: An exploration between personality traits and cultural goals. The Five-Factor model of personality across cultures. NY: Kluwer Academic Publisher. pp. 197–227.
- Piedmont, R. L.; Bain, E.; McCrae, R. R.; Costa, P. T. Jr. (2002). McCrae, R. R.; Allik, J., eds. The applicability of Five Factor Model in sub Saharan culture: The NEO PI-R in Shona. The Five-Factor model of personality across cultures. NY: Kluwer Academic Publisher. pp. 155–174.
- Rolland, J. P. (2000, July). Cross-cultural validity of the five factor model of personality. Paper presented at the XXVIIth International Congress of Psychology, Stockholm, Sweden.
- McCrae, R. R.; Costa, P. T. Jr.; Pedroso De Lima, M. P.; Simões, A.; Ostendorf, F.; Angleitner, A.; Marusić, I.; Bratko, D.; Caprara, G. V.; Barbaranelli, Claudio; Chae, Joon-Ho; Piedmont, Ralph L.; et al. (1999). "Age differences in personality across the adult life span: Parallels in five cultures". Developmental Psychology. 35 (2): 466–477. doi:10.1037/0012-16184.108.40.2066. PMID 10082017.
- McCrae, R. R. (2001). "Trait psychology and culture: exploring intercultural comparisons". Journal of Personality. 69 (6): 819–846. doi:10.1111/1467-6494.696166. PMID 11767820.
- McCrae, R. R.; Terracciano, A. (2005). "Personality Profiles of Cultures: Aggregate Personality Traits". Journal of Personality and Social Psychology. 89 (3): 407–425. doi:10.1037/0022-35220.127.116.117. PMID 16248722.
- Piedmont, Ralph L.; Braganza, Dinesh J. (2015). "Psychometric evaluation of responses to the NEO PI-3 in a multi-ethnic sample of adults in India.". Psychological Assessment. 27 (4): 1253–1263. doi:10.1037/pas0000135.
- Persson M.-L. Wasserman D.; G. Jonsson E.; Bergman H.; Terenius L.; Gyllander A.; Neiman J.; Geijer T. (July 2000). "Search for the influence of the tyrosine hydroxylase (TCAT)n repeat polymorphism on personality traits". Psychiatry Research. 95 (1): 1–8. doi:10.1016/S0165-1781(00)00160-8.
- Mamoru Tochigi, Takeshi Otowa, Hiroyuki Hibino, Chieko Kato, Toshiyuki Otani, Tadashi Umekage, Takeshi Utsumi, Nobumasa Kato, Tsukasa Sasaki (March 2006). "Combined analysis of association between personality traits and three functional polymorphisms in the tyrosine hydroxylase, monoamine oxidase A and catechol-O-meethyltransferase genes". Neuroscience Research. 54 (3): 180–185. doi:10.1016/j.neures.2005.11.003. PMID 16360899.
- Lesch, K. P., Bengel, D., Heils, A., Sabol, S., Greenberg, B., Petri, S., Benjamin, C., Hamer, D. & Murphy, D. (1996). "Association of Anxiety-Related Traits with a Polymorphism in the Serotonin Transporter Gene Regulatory Region". Science. 274 (5292): 1527–1530. doi:10.1126/science.274.5292.1527. PMID 8929413.