The Secular Trend, Women, Intelligence, Aggressive Males, and the Future:  A Current Sign of Human Evolution?


Copyright 2006, James Michael Howard, Fayetteville, Arkansas, U.S.A.


Re: “The Condition of Education”


The Associated Press reported findings of the study, “The Condition of Education,” June, 2006.  The basic thrust of the report is that women are gaining in education in “male” areas.  Some of the findings are: “Women now earn the majority of diplomas in fields men used to dominate – from biology to business – and have caught up in pursuit of law, medicine and other advanced degrees.”  “Federal statistics released Thursday [June 1] show that in many ways, the sex gap in college enrollment is widening.  Women earn the majority of bachelor’ degrees in business, biological sciences, social sciences and history.”  “In undergraduate and graduate disciplines where women trail men, they are gaining ground, earning larger numbers of degrees in math, physical sciences and agriculture.”  “Women now account for about half the enrollment in professional programs such as law, medicine and optometry.  That is up from 22 percent a generation ago.”  “The number of women enrolled in undergraduate classes has grown more than twice as fast as it has for men on campus by at least 2 million, and the gap is growing.”  “The enrollment of men in professional degree programs is declining.”


Some people who try to explain the foregoing have attributed this major change to girls receiving more attention than boys, for various reasons.  I suggest this phenomenon is due to biological changes in our population that are the basis of human evolution.


It is my hypothesis that human evolution is driven by increases in testosterone (“Androgens in Human Evolution,” Rivista di Biologia / Biology Forum 2001; 94: 345-362).  The mechanism involves differential reproduction, that is, some women reproduce faster than others.  Women of higher testosterone reproduce faster than women of lower testosterone.  Women of higher testosterone have increased sex drive and are more aggressive.


I suggest this mechanism is visible within our society as the “secular trend,” the increase in size and earlier puberty in children.  (Yes, human evolution is clearly visible now and in the past.)  The trend is real and robust in the U.S.A. (" Secular trends in height among children during 2 decades," Archives of Pediatric and Adolescent Medicine 2000; 154: 155-161).  I suggest the trend is caused by differential reproduction, that is, women of higher testosterone reproduce faster than women of lower testosterone and their percentage increases faster within the population over time.  With each generation, the percentage of women of higher testosterone increases.


This also increases the percentage of fetuses exposed to increased testosterone within the population over time.  Exposure of the fetal brain to increased testosterone may produce differential effects, depending upon total testosterone levels, that is, maternal testosterone and fetal testosterone.  Too much testosterone is not a good thing for learning.  Male fetuses are exposed to both maternal testosterone and their own testosterone.


It is known that excessive testosterone is significantly connected to learning disabilities: “Salivary testosterone levels in 264 children without learning disabilities (133 males, 131 females) were measured and compared to that in 32 children with learning disabilities (25 males, 7 females). The presence of learning disabilities was significantly associated with higher salivary testosterone.” (Physiology & Behavior 1993; 53: 583-6).  Another study, with the caveat that the subjects were 47,XXY males, found a relationship quite similar to the findings of the literacy section of the Arkansas Benchmark Exams: “The findings indicated that verbal IQs measured prior to puberty, during puberty and at mid-adolescence were strongly related to relatively early pubertal onset and testosterone levels.” (Clinical Genetics 1992; 42: 31-4).


Studies in normal populations indicate the effect of testosterone levels on men and women.  The cognitive performance of normal men and women was studied, grouped according to whether the subjects had relatively high or low salivary testosterone (T) concentrations. Men with lower T performed better than other groups on measures of spatial/mathematical ability, tasks at which men normally excel. Women with high T scored higher than low-T women on these same measures. T concentrations did not relate significantly to scores on tests that usually favor women or that do not typically show a sex difference. These results support suggestions of a nonlinear relationship between T concentrations and spatial ability, and demonstrate some task specificity in this respect.  (Psychoneuroendocrinology. 1991; 16: 323-34)


I suggest the preceding two paragraphs combine to explain what is happening to men and women and learning in our population.  Too much testosterone reduces learning ability while too little also reduces learning ability.  This plus the secular trend may explain what is occurring in our educational institutions.


In the past, the majority of girls were not exposed to sufficient testosterone to activate their brains with increased androgen receptors, the sites where testosterone affects the brain.  In the past, the majority of boys were exposed to sufficient levels of testosterone to activate their brains with increased androgen receptors.  Approaching puberty, and after, testosterone levels in both sexes increase and exert their effects via androgen receptors.  This activates the brain.  In the past, a lot of boys and men produced sufficient levels of testosterone that did not produce learning disabilities early in life and produced increased stimulation from puberty forward.  Girls did not produce these levels.  The educational institutions were populated by a majority of men in fields in which testosterone produced an advantage in learning in the sciences.


As the secular trend continues, the percentage of female fetuses exposed to higher maternal testosterone increases.  This increases the effectiveness of their testosterone on learning ability.  Remember from above that women of higher testosterone scored higher in “male” tasks.  As the secular trend continues, the educational institutions are increasingly populated by women in fields in which testosterone produces an advantage.  As the secular trend continues, an increasing percentage of male fetuses are exposed to increased maternal testosterone and their own testosterone.  This causes a slight increase in learning problems for an increasing percentage of males.  These males do not attend, or do not succeed at, college.  Black males are the group with the highest percentages of problems in education.  Black mothers produce more testosterone than white mothers (Cancer Causes Control. 2003; 14: 347-55).  Black males produce significantly more testosterone than while males, (J Natl Cancer Inst 1986; 76: 45), and black females produce more testosterone than white females, (J Clin Endocrin Metab 1996; 81: 1108).  Black male fetuses are exposed to more testosterone in utero and at puberty than other groups.



I think this phenomenon has been occurring throughout prehistory and recorded history.  I suggest this is why civilization develops, then declines.  That is, as testosterone increases with a population, the learning abilities increased by testosterone increase.  These abilities are often in the sciences so the populations advance.  As the level of testosterone increases too much, these same abilities decline so the populations decline.


I have just explained that these abilities of women are increasing now and I think they increased in the same manner in past civilizations.  The problem is that as men increase in testosterone and begin the decline in thinking abilities, men, as a group, become less intelligent and more aggressive.  I think this increase in aggression and reduced thinking ability forces women into submission so their increasing thinking abilities are lost to the civilizations.  I suggest that subjugation of women by “dumb, aggressive” men is often characteristic of the living remnants of past, vibrant civilizations. 


The article in which I read about 2006 “Condition of Education” also pointed out that women in the United States earn less for their degrees than men.  I suggest this may be part of our subjugation of women and it may portend a very negative trend in our population that may be a repeat of the decline of other civilizations.  If we do not let our women, who are increasingly brighter than our men, take control of this country, we may regret it.  The rise of “anti-science” religions which subjugate women is rising in the U.S.