April 23, 2010

Exit genetic determinism: example of genes-environment interaction

Yesterday's post Bye bye genetic determinism, described a relatively new view on the influence of genes on how we are and become. Briefly, it states that genes are not the simple causal agents of our traits we once thought they were. Instead, genes interact constantly with a multitude of environmental factors. It is not simply the genes, but the genes-environment interaction (GxE) which determines how we are, what we do and how we develop.

One dramatic demonstration of this genes-environment interaction dates back to 1958 when researchers Rod Cooper and John Zubek did an experiment with rats. They worked with two groups of rats: 1) maze-bright rats, rats who had consistently performed well in mazes, 2) maze-dull rats, rats who had consistently performed poorly in mazes. They tested the performance of these rats in three types of environments: 1) impoverished environments with no stimulation whatsoever, 2) normal environments, with ordinary walls and a moderate amount of exercise, and 3) enriched environments with walls painted in bright patterns and many stimulating toys: ramps, mirros, swings, slides, bells, etc. The graph below shows how dramatic the genes-environment interaction effects were (click to enlarge). 

Full reference to the orignal article: Cooper RM & Zubek JP (1958). "Effects of enriched and restricted early environments on the learning ability of bright and dull rats". Canadian Journal of Psychology 12 (3): 159–164. PMID 13573245


  1. Coert, great articles. Made for interesting discussions with my scientifically oriented children!

  2. Important topic.

    On the interactionist model also see Matt Ridley's "Nature via Nurture" (or "The Agile Gene")

    Reviews at -->




    I also liked Gary Marcus' take on the origin of the mind in interactionist terms:


  3. Hi Todd, thanks. I agree. I've read all his books and think they're great! Especially nature via nurture

  4. Gary Marcus is a cog sci prof at New York University in the States. I think he has a Wikipedia bio article.

    His first book was a geeky but revealing compare and contrast of the connectionist and rule-based models of mind in cognitive science. People who have some comp sci sophistication and wonder about the specifics of how the mind compares with a computer would love it. It really makes you think about what a neural network is capable of, what rules are capable of, and what the mind does that goes beyond either of these things (or perhaps combines them).

    Then Birth of the Mind was a broad take on how genes may wire minds, emphasizing the interaction aspect.

    His third, "Kluge" was about how minds are wired up from artifacts. It has some useful insights, but for me it lost the techie edge that really had me enthused about his previous two books.

  5. good to see you back todd
    still looking forward to writing something together sometime

  6. Why can't I find a description of this experiment from an academic source? I can't cite a blog and I can't cite a journal unless I've read it. Even if I did acquire this journal, it would be a whole lot more credible if I could provide a link to an academic source which describes the results of the experiment: http://www.ncbi.nlm.nih.gov/pubmed/13573245

  7. Full reference to the orignal article: Cooper RM & Zubek JP (1958). "Effects of enriched and restricted early environments on the learning ability of bright and dull rats". Canadian Journal of Psychology 12 (3): 159–164. PMID 13573245


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