On Dec 16, 2013, at 2:41 PM, Philippe Gervaix wrote: > One of my students presented an end of school project on the sources of > happiness, and quoted a "50/40/10" proportion as being scientifically > established: 50% attributed to genes, 40% to "us" and 10% left to ouside > events.
On Dec 17, 2013, at 9:58 AM, John Kulig wrote: > The 50/40/10 is probably accurate. It's close to 50% based on data from > Caprara et al. (2009) Human optimal functioning: The genetics of positive > orientation toward self, life, and the future. _Behavioral Genetics_. Also, > Plomin et al recent book "Behavioral Genetics" (2013) cites 30 to 60% > genetics on "subjective well being"..... One simple thing I stress with > students is that the 50% figure refers to amount of _variance_ so it cannot > be applied to individuals, only populations. [emphasis added] Thanks, John. That last sentence is what most people forget when they make statements such as 50% of X is due to genes. And just to clarify John's statement further, heritability refers to the amount of variance in X associated with variation in genes in a particular population (I'm ignoring the difference between broad and narrow heritability): it cannot be generalized to other populations, nor even to that population in the past or the future. The latter is especially important because things change. For example, the heritability of height is quite high currently in "developed" countries because the majority of people have enough to eat: malnutrition is not a problem for most. Thus, variation in height due to variation in environmental factors is much smaller in developed countries relative to variation in height due to variation in genetic factors. However, during historical time periods when there were wide variations in food consumption in those very same countries, the heritability of height would have been much smaller. I just found the following article, which might be a good one for students who want to understand the concept of heritability better: http://www.nature.com/scitable/topicpage/estimating-trait-heritability-46889 Best, Jeff P.S. My bona fides: in a "former life," I was a young researcher in the area of behavior genetics and evolution. Now, I'm getting to be an old teacher of all kinds of things. -- --------------------------------------------------------------------------------- Jeffry Ricker, Ph.D. Professor of Psychology --------------------------------------------------------------------------------- Scottsdale Community College 9000 E. Chaparral Road Scottsdale, AZ 85256-2626 Office: SB-123 Phone: (480) 423-6213 Fax: (480) 423-6298 --- You are currently subscribed to tips as: arch...@jab.org. To unsubscribe click here: http://fsulist.frostburg.edu/u?id=13090.68da6e6e5325aa33287ff385b70df5d5&n=T&l=tips&o=31539 or send a blank email to leave-31539-13090.68da6e6e5325aa33287ff385b70df...@fsulist.frostburg.edu
