For many years, candidates have been asked to report whether any psychiatric disorders occur among their parents or siblings. Below are the available statistics of that field, when "yes" is coded as 1 and "no" is coded as 0.
Note: Since the values are either 0 or 1, the above means can be understood as proportions, so that for instance 0.24 means that 24 percent has answered "yes".
Weighted average of correlations: -0.133 (N = 3671, weighted sum = -487.95)
Conservatively estimated minimum g loading: -0.36
Remark: Just like disorders in the candidates themselves, disorders in parents or siblings correlate negatively with I.Q. and g.
Weighted average of correlations: -0.138 (N = 991, weighted sum = -136.35)
Remark: Tests by others reveal a similar negative correlation.
Weighted average of correlations: -0.226 (N = 113, weighted sum = -25.59)
Conservatively estimated minimum g loading among females: -0.48
Remark: As often, the g loading (and correlation) in females is higher (negative in this case) than the overall one. Since this is seen in I.Q. test statistical reports too, it may just be that high-range tests measure g better in females than in males, and may have nothing to do with the correlation between disorders and g as such.
These are estimated g factor loadings, but against homogeneous tests (containing only particular item types) as opposed to non-compound heterogeneous tests. Although tending to surprise the lay person, it is not uncommon for tests to have high loadings on item types they do not actually contain themselves. Such loadings reflect the empirical fact that most tests for mental abilities measure primarily g, regardless of their contents; that the major part of test score variance is caused by g, and only a minor part by factors germane to particular item types. It is of key importance to understand that this is a fact of nature, a natural phenomenon, and not something that was built into the tests by the test constructors.
|Type||n||g loading of Disorders (parents and siblings) on that type|
N = 2970
Balanced g loading = -0.36
Correlation of this test with national average I.Q.'s published by Lynn and Vanhanen:
|P.S.I.A. Neurotic - Revision 2007||75||0.28|
|P.S.I.A. Introverted - Revision 2007||75||0.25|
|P.S.I.A. True - Revision 2007||75||0.24|
|Gifted Adult's Inventory of Aspergerisms||90||0.24|
|P.S.I.A. Cold - Revision 2007||75||0.21|
|P.S.I.A. Aspergoid - Revision 2007||75||0.20|
|P.S.I.A. System factor - Revision 2007||75||0.19|
|Observed associative horizon||38||0.18|
|Cooijmans Inventory of Neo-Marxist Attitudes||44||0.18|
|P.S.I.A. Orderly - Revision 2007||75||0.16|
|P.S.I.A. Deviance factor - Revision 2007||75||0.14|
|P.S.I.A. Ethics factor - Revision 2007||75||0.14|
|P.S.I.A. Extreme - Revision 2007||75||0.08|
|P.S.I.A. Cruel - Revision 2007||75||0.07|
|P.S.I.A. Just - Revision 2007||75||0.04|
|P.S.I.A. Rare - Revision 2007||75||0.01|
|Mother's educational level||978||-0.01|
|Year of birth||1022||-0.03|
|Father's educational level||969||-0.04|
|P.S.I.A. Antisocial - Revision 2007||75||-0.10|
|P.S.I.A. Rational - Revision 2007||75||-0.13|
Observation: The highest correlation is with disorders in the candidates themselves.