Cold Winters Theory
The Cold Winters Theory (CWT) posits that median population IQs vary geographically due to the difficulty of surviving harsh colder climates. Accordingly, populations in warmer areas would not face the same selective pressures for IQ as populations in that live in colder environments. The hypothesis may explain how racial IQ differences could emerge and remain stable.
Origins
In the 1990s, Richard Lynn and J. Philippe Rushton published hypotheses regarding the evolutionary origin of human intelligence in cold environments.[1]
Evidence
When plotting IQ against winter high temperatures there is a negative correlation value of -.74 demonstrating a correlation exists.[1]
Criticism
There are number of outlier populations that CWT does not directly explain, such as high IQ southeast Asian populations living in warm environments, or the lower average IQs of the indigenous arctic/subarctic populations.[2] The former may be explained by recent migrations from cold to warmer populations. However, the lower IQs of the arctic populations is more difficult to explain by temperature alone as winters in the arctic are longer and colder than the environments of higher IQ populations. Therefore, winter temperature alone cannot be the sole cause of the increase in intelligence. An alternative explanation for the correlation is the temperature range of an area[1], where the larger differences would select for humans that can plan and adjust for strategies for surviving the extremes of winter and summer.
References
- ↑ 1.0 1.1 1.2 Donald I. Templer, John S. Stephens (2014) The relationship between IQ and climatic variables in African and Eurasian countries, Intelligence, Volume 46. https://www.sciencedirect.com/science/article/abs/pii/S0160289614000877?via%3Dihub
- ↑ Lynn, R. (2015) Race Differences in Intelligence: An Evolutionary Analysis, Second Revised Edition. https://www.intelligence-humaine.com/wp-content/uploads/2019/03/Race-Differences-in-Intelligence-second-edition-2015-1.pdf