As with all studies of complex things, it would be good to see the details. Questions good to ask would include whether the range of type A personality seen in these 4 villages in the Mediterranean is as great as the range we in North America are accustomed to. It would also be good to determine just how related the individuals are, as the degree of genetic variability will also infliuence h squared - not to mention the variability of a host of other factotrs - such as diet, which all can affect the external validity of any one study. I'm not the expert on personality, but isn't "Type A" a poorly defined and outdated personality factor? I find it difficult to imagine that complex areas such as the relationship between personality and heart disease can be easily classified as "true" or "false."
----------------------------- John W. Kulig Professor of Psychology Director, Psychology Honors Plymouth State University Plymouth NH 03264 ----------------------------- -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Sunday, September 03, 2006 11:35 AM To: Teaching in the Psychological Sciences (TIPS) Subject: [tips] More mythbusting: Type A and heart disease T'ain't so. http://www.sciencedaily.com/releases/2006/08/060830075738.htm (Note: This study was not carried out on people who eat sardines.) Stephen Pilia, G. et al (2006). Heritability of Cardiovascular and Personality Traits in 6,148 Sardinians, v. 2, August [http://tinyurl.com/o2moj] Synopsis Genetic analysis of complex traits, which are influenced by many different variables, is difficult because different genes and environmental factors can affect each individual. To simplify analysis, the authors turned to Sardinia, one of the rare, relatively isolated populations. They recruited 6,148 participants, aged 14-102 y, from four neighboring towns. Their sample includes many related individuals, including, for example, approximately 5,000 pairs of brothers and sisters. The authors measured 98 traits in each individual, including different aspects of blood composition and several cardiovascular and personality measures. Here, the authors evaluate the overall impact of genes and environment on each trait and show that genes can explain many of the differences and similarities between individuals. Genetic influences were typically larger in females and in younger individuals, but interesting exceptions were observed. For example, genetic factors accounted for approximately 26% of the variation in blood pressure for those more than 42 y old, but only for approximately 8% in younger individuals. Their analysis also showed that the same genetic factor could influence multiple traits, for example by affecting multiple features of personality or of cardiovascular function. DNA analyses of this cohort will eventually allow researchers to identify genes that affect each of the traits studied, including important risk factors for cardiovascular disease. ----------------------------------------------------------------- Stephen L. Black, Ph.D. Department of Psychology Bishop's University e-mail: [EMAIL PROTECTED] 2600 College St. Sherbrooke QC J1M 0C8 Canada Dept web page at http://www.ubishops.ca/ccc/div/soc/psy TIPS discussion list for psychology teachers at http://faculty.frostburg.edu/psyc/southerly/tips/index.htm ----------------------------------------------------------------------- --- To make changes to your subscription go to: http://acsun.frostburg.edu/cgi-bin/lyris.pl?enter=tips&text_mode=0&lang=engl ish --- To make changes to your subscription go to: http://acsun.frostburg.edu/cgi-bin/lyris.pl?enter=tips&text_mode=0&lang=english
