The Intelligence Paradox: Why the Intelligent Choice Isn't Always the Smart One - Satoshi Kanazawa 2012

So Are Asians Really More Nocturnal than Others?
Why Night Owls Are More Intelligent than Morning Larks

So are Asians really more nocturnal than other races, as was my impression on my frequent trips to Countdown in Christchurch at three o’clock in the morning? I don't have data on Kiwis, but Add Health data on Americans do suggest that they are.

Compared to all other races (whites, blacks, and Native Americans), Asians go to bed significantly later on weeknights (00:43 vs. 00:08) and on weekend nights (01:27 vs. 01:12). However, Asians do not wake up significantly later than others either on weekdays (07:38 vs. 07:32) or on weekends (10:20 vs. 10:18). In general, races differ significantly from each other in what time they go to bed, both on weeknights and weekend nights, but they do not differ significantly from each other in what time they wake up, either on weekdays or on weekends.

So it appears that my casual observations at Countdown in Christchurch so many years ago may have some empirical basis. Compared to other races, Asians do appear to stay up (and, presumably, shop for groceries, among other things) later into the night. The bivariate associations between being Asian and nocturnality (what time they go to bed at night), represented in Figures 8.5 and 8.6, remain statistically significant even when childhood IQ is controlled for. Even net of childhood intelligence, Asians go to bed significantly later than others every night. So it is not because they are slightly more intelligent than other races that Asians are more nocturnal.

Figure 8.5 Association between race and weekday time to go to bed

Figure 8.6 Association between race and weekend time to go to bed

Figure 8.7 Association between race and weekday time to wake up

Figure 8.8 Association between race and weekend time to wake up

However, the association disappears once I control for all the other social and demographic variables included in the multiple regression analyses (age, sex, current marital status, parental status, education, income, religion, whether currently in school, and the number of hours worked). In fact, the only significant effect of race in the multiple regression analyses is being black. Compared to whites (the reference category), blacks go to bed later on weekends (but not on weeknights) and wake up later on weekends (but not on weekdays).²⁵

Unfortunately, the Intelligence Paradox is completely mute on genuine race differences in nocturnality (or anything else) net of general intelligence. So I do not know why Asians or blacks stay up later into the night or wake up later in the morning.

Notes

1. http://www.psychologytoday.com/blog/the-scientific-fundamentalist/200809/the-50-0-50-rule-in-action-partisan-attachmen

2. Fowler and Dawes (2008)

3. Kanazawa (1998, 2000)

4. Turkheimer (2000)

5. Alford, Funk and Hibbing (2005); Eaves and Eysenck (1974)

6. Bouchard et al. (1999); Koenig et al (2005)

7. Kanazawa (2010a)

8. Vitaterna, Takahashi and Turek (2001, p. 85)

9. Klein, Moore and Reppert (1991)

10. King and Takahashi (2000)

11. Hur (2007)

12. Vitaterna et al. (2001, p. 90, emphasis added)

13. Dyer et al. (2009, p. 8964); Ross (2000)

14. Levinson (1991—1995)

15. Chagnon (1992); Cronk (2004); Hill and Hurtado (1996); Lee (1979); Whitten (1976)

16. Chagnon (1992, p. 129)

17. Cronk (2004, p. 88)

18. Chagnon (1992, p. 132)

19. Cronk (2004, p. 93)

20. Hill and Hurtado (1996, p. 65)

21. Cronk (2004, p. 92)

22. Ash and Gallup (2007); Bailey and Geary (2009); Kanazawa (2008)

23. Kanazawa and Perina (2009)

24. Roberts and Kyllonen (1999)

25. Kanazawa and Perina (2009)