Biology ETDs

Publication Date



We show that infectious disease is a major contributor to the worldwide distribution of human cognitive ability, as measured by psychometric IQ. In areas where infectious disease is high, average human intelligence tends to be lower, and in areas where infectious disease is low, average human intelligence tends to be higher. In separate studies, we tested this across world nations (chapter 2) and across states of the USA (chapter 3). In efforts to disseminate our research to wider audiences, I reviewed the findings contained in chapters 2 and 3 using language that is accessible to non-biologists (chapter 4). Although it contains no original research, this chapter makes our research more readily available to people in non-biological fields, such as economics and political science, who may be interested in our findings. An early prediction we made, based on our first analysis, was that infectious disease could account for the apparent link between IQ and rates of asthma that other research has discovered (chapter 5). Additionally, this chapter attempts to reconcile the predictions made by several related hypotheses.




Intelligence, Development, Parasite-stress hypothesis, Hygiene hypothesis, Asthma, Developmental stability, Cognitive development, Life History, Brain growth, Flynn Effect, Parasites, Biogeography

Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

Watson, Paul

Second Committee Member

Kodric-Brown, Astrid

Third Committee Member

Gangestad, Steve