Whitley, Elise et al. – 2016 – Variations in cognitive abilities across the life course
- Five tests: Word recall, verbal fluency, and subtraction (loading ~0.5 on g), and number sequence and numerical problem solving (loading ~0.7 on g).
- Males score about 4 IQ points more on the derived g-factor of cognitive ability.
- … though this result should be treated with caution on account of: (a) g having different structure across the sexes; (b) it is not an exception to a common problem in IQ and sex studies, namely, the undersampling of men with lower cognitive ability.
- Better subjective health was associated with higher IQ.
- The overall pattern across age was a plateau from the late teens to age 65, then a steep fall soon thereafter.
EDIT: Emil Kirkegaard had a closer look at the results, including a nicer graph of the age/sex results:
My guess is that the intercept bias/invariance has to do with the composition of the battery. There were only 5 tests, and their breakdown was: 3 math, 1 verbal, 1 memory. Women had better memory but there was no difference in verbal fluency (this is a common finding despite what you have been told). So, the problem likely is that the g factor is colored because 60% of the tests were about math, and that men have an advantage on the math group factor.