On the Real Magnitude of Psychological Sex Differences
A comprehensive evolutionary theory of sex differences will benefit from an accurate assessment of their magnitude across different psychological domains. This article shows that mainstream research has severely underestimated the magnitude of psychological sex differences; the reason lies in the co...
| Main Author: | |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
SAGE Publishing
2009-04-01
|
| Series: | Evolutionary Psychology |
| Online Access: | https://doi.org/10.1177/147470490900700209 |
| _version_ | 1818354827920408576 |
|---|---|
| author | Marco Del Giudice |
| author_facet | Marco Del Giudice |
| author_sort | Marco Del Giudice |
| collection | DOAJ |
| description | A comprehensive evolutionary theory of sex differences will benefit from an accurate assessment of their magnitude across different psychological domains. This article shows that mainstream research has severely underestimated the magnitude of psychological sex differences; the reason lies in the common practice of measuring multidimensional differences one dimension at a time, without integrating them into a proper multivariate effect size (ES). Employing the Mahalanobis distance D (the multivariate generalization of Cohen's d ) results in more accurate, and predictably larger, estimates of overall sex differences in multidimensional constructs. Two real-world examples are presented: (1) In a published dataset on Big Five personality traits, sex differences on individual scales averaged d = .27, a typical ES conventionally regarded as “small.” However, the overall difference was D = .84 (disattenuated D = .98), implying considerable statistical separation between male and female distributions. (2) In a recent meta-analytic summary of sex differences in aggression, the individual ESs averaged d = .34. However, the overall difference was estimated at D = .75 – .80 (disattenuated D = .89–1.01). In many psychological domains, sex differences may be substantially larger than previously acknowledged. |
| first_indexed | 2024-12-13T19:31:37Z |
| format | Article |
| id | doaj.art-067373e772cc4ef0b4bc60a862a69f07 |
| institution | Directory Open Access Journal |
| issn | 1474-7049 |
| language | English |
| last_indexed | 2024-12-13T19:31:37Z |
| publishDate | 2009-04-01 |
| publisher | SAGE Publishing |
| record_format | Article |
| series | Evolutionary Psychology |
| spelling | doaj.art-067373e772cc4ef0b4bc60a862a69f072022-12-21T23:33:54ZengSAGE PublishingEvolutionary Psychology1474-70492009-04-01710.1177/14747049090070020910.1177_147470490900700209On the Real Magnitude of Psychological Sex DifferencesMarco Del GiudiceA comprehensive evolutionary theory of sex differences will benefit from an accurate assessment of their magnitude across different psychological domains. This article shows that mainstream research has severely underestimated the magnitude of psychological sex differences; the reason lies in the common practice of measuring multidimensional differences one dimension at a time, without integrating them into a proper multivariate effect size (ES). Employing the Mahalanobis distance D (the multivariate generalization of Cohen's d ) results in more accurate, and predictably larger, estimates of overall sex differences in multidimensional constructs. Two real-world examples are presented: (1) In a published dataset on Big Five personality traits, sex differences on individual scales averaged d = .27, a typical ES conventionally regarded as “small.” However, the overall difference was D = .84 (disattenuated D = .98), implying considerable statistical separation between male and female distributions. (2) In a recent meta-analytic summary of sex differences in aggression, the individual ESs averaged d = .34. However, the overall difference was estimated at D = .75 – .80 (disattenuated D = .89–1.01). In many psychological domains, sex differences may be substantially larger than previously acknowledged.https://doi.org/10.1177/147470490900700209 |
| spellingShingle | Marco Del Giudice On the Real Magnitude of Psychological Sex Differences Evolutionary Psychology |
| title | On the Real Magnitude of Psychological Sex Differences |
| title_full | On the Real Magnitude of Psychological Sex Differences |
| title_fullStr | On the Real Magnitude of Psychological Sex Differences |
| title_full_unstemmed | On the Real Magnitude of Psychological Sex Differences |
| title_short | On the Real Magnitude of Psychological Sex Differences |
| title_sort | on the real magnitude of psychological sex differences |
| url | https://doi.org/10.1177/147470490900700209 |
| work_keys_str_mv | AT marcodelgiudice ontherealmagnitudeofpsychologicalsexdifferences |