Before revision: Criticism However, as regards certain personality traits, like the degree of "introvertness" or of "sourness" , there was an research carried out by psychologists at Michigan State University and the University of Minnesota, based on a relatively huge data base of 1,296 couples who have been married for an average of 19.8 years, suggesting that only the degree of aggressivity actually tended to converge.
After revision: Criticism However, as regards certain personality traits, like the degree of introversion or of sourness , there was an research carried out by psychologists at Michigan State University and the University of Minnesota, based on a relatively huge data base of 1,296 couples who have been married for an average of 19.8 years, suggesting that only the degree of aggressivity actually tended to converge.