Human Evolution in Modern Society


(Copyright James Michael Howard, Fayetteville, Arkansas, U.S.A.  …document created January 17, 2000)


(I wrote this years ago but did not publish it.  A new piece of research has provided direct support for my ideas so I am now putting this at my website in 2006.  The NEW SUPPORT is immediately below this document.)


Further Support of the Howard Theory of Human Evolution




James Michael Howard

Fayetteville, Arkansas, U.S.A.


This document is designed to explain a number of phenomena, occurring within society, which are being noticed by the majority of people.  While it is being eroded, the most accepted model of human behavior is the environmental model.  That is, our behavior patterns are primarily formed by outside influences, such as parents, siblings, teachers, etc., and the places where we “grow-up.”  While most people agree to some combination of environment and genetic influences, most lean heavily toward the environment.  Some still think children “learn” to walk.  This is because most are not aware that walking is directly dependent upon myelination of the spinal nerves that serve that function.  So, they assume that their “teaching” about that time is the cause.  They lack information about spinal nerve development.  The following is designed to explain some new findings (new information) which further tip the balance towards “genes” in determining human behavior.  This happens to also directly support my explanation of human evolution.  I suggest that the same mechanism that caused human evolution, in the past, is extant and ongoing.


My explanation of human evolution is based on the impact of hormones on expression of hominid DNA.  While very small differences in DNA probably existed between the hominids, I think differential expression of essentially identical DNA’s created differences in the various hominids and, therefore, the fossil record.  Since chimpanzee and human DNA are about 99% identical, the DNA of hominids must have been even closer.  Basically, I suggest hominid group dynamics caused the formation of subordinate groups which eventually exhibited permanent hormonal differences.  That is, individuals of a “base” group forced individuals of a “subordinate” group away from favorable “breed and feed” sites.  Competition for food and reproduction resulted in less aggressive individuals being forced out.  When this occurs sufficiently enough to move subordinate groups into sufficiently differing ecosystems, advantages accrue to some, slightly different, individuals who have a natural survival advantage.  Those that can live start reproducing in the new place.  Some of the “refugees” form new “feed and breed” sites.  Once formed, competition for food and reproduction, again, forces subordinate individuals to flee.  The situation always repeats.  Since the DNA’s of each base group and subordinate group were probably changed very little by these forced migrations, I suggest the survival advantage of refugee groups entering new, more physically demanding ecosystems, rests in hormonal differences.  Those individuals, that survived, lived to produce offspring and form new groups composed of individuals alike in hormones.  These hormonal differences produced differences in gene expression that produced individuals of differing physiology and anatomy that culminated in “Homo sapiens.”  (Please see my explanation of human evolution at  for greater detail.  This is a published paper of my theory of human evolution; 2001.)


In 1985, I developed my explanation of the “flight or fight” mechanism; it resulted from my work on my explanation of human evolution.  Basically, I suggested that the decision to fight, or run from, an adversary rested in the ratio of two hormones, dehydroepiandrosterone (DHEA) and cortisol, the two major hormones produced by the adrenal glands.  At its most basic, my reasoning was that DHEA evolved to push biological mechanisms forward, that is cellular mechanisms.  Since complex behavioral patterns (neurological mechanisms) result from evolution of cellular mechanisms, DHEA pushes behavior.  In terms of amount, DHEA is the major adrenal hormone; cortisol is the other.  Cortisol is produced during stress; cortisol produces stress.  I reasoned that cortisol evolved to counteract DHEA, that is, to stop the actions of DHEA.  If one’s ratio of DHEA to cortisol is higher than DHEA, a behavior goes forward; one fights.  If the ratio favors cortisol, one flees out of fear.  According to my explanation, then, lack of cortisol would indicate a predisposition to fight.


January 14, 2000, the Associated Press reviewed the findings of K. McBurnett, et al., from the Archives of General Psychiatry 2000; 57: 38-43.  McBurnett, et al., found that “Low cortisol levels were associated with persistence and early onset of aggression, particularly when measures of cortisol concentrations were pooled.  Boys with low cortisol concentrations at both time points exhibited triple the number of aggressive symptoms and were named as most aggressive by peers 3 times as often as boys who had higher cortisol concentrations at either sampling time.”  In other words, low cortisol results in the “fight” response.  The AP quotes Dr. McBurnett to say: “Perhaps what we’re dealing with here is a biological propensity that’s resistant to treatment, which is very troubling.”  …also: “Low cortisol would make you bold,” he said.  In youngsters with low levels of the hormone, “it doesn’t bother them when you do things to them.  It’s hard to make them behave.”


It has been known for some time that low cortisol is characteristic of habitual, antisocial, violent offenders. “Only among the habitually violent offenders with antisocial personality were the values [of cortisol] low when compared with other violent offenders, antisocial personality without the habitually violent tendency, and male clinic personnel.  Poor motivation already in school, truancy, attention deficit and undersocialized aggressive conduct disorder seemed to be connected with the low cortisol levels.”  (Acta Psychiatr Scand 1985; 72: 40-4)  Low cortisol runs in families who exhibit conduct disorder and antisocial personality disorder (Psychiatry Res 1993: 46: 9-17).  It has “genetic” characteristics.  Young individuals who exhibit conduct disorder are also more likely to join gangs (J Abnorm Child Psychol 1999; 27: 261-76).  Low cortisol is also found in individuals who cannot control their behavior, that is, attention deficit/hyperactivity disorder (Biol Psychiatry 1998; 44: 72-4).  These individuals are best described by some combination of: habitual, antisocial, and violent.  Their cortisol is low; their ratio of cortisol to DHEA is low.


The individuals, described above, things being equal, would probably win in a “fight or flight” confrontation.  They have no fear and will not be intimidated.  However, things are seldom equal, and that brings me to the other hormone involved in my theory of human evolution, that is, testosterone.  Human males and females produce more testosterone than male and female chimpanzees.  The other element in individuals of “base” groups that causes them to be more aggressive and more powerful (unequal, if you will) is increased testosterone.  I suggest increased testosterone in successive hominids is the driving force of evolution.  Increased testosterone would increase sexual drive in both males and females; their numbers would increase faster than lower testosterone types.  The increased aggressiveness and sexuality that increased testosterone provokes, along with reduced cortisol, in “base” groups would quickly build groups that would often create “refugees.”  That is, many lower testosterone individuals would be pushed into new ecosystems by large, aggressive, base groups.  This combination would speed human evolution, that is, changes in hormones, according to my theory.


Testosterone is connected to offensive behaviors: “A positive relation between testosterone and offensive behaviors was obtained in the sense that the greater the hormonal titer, the greater the number of threats, fights, and attacks.” (Physiol Behav 1999; 68: 205-9).  This is also characteristic of testosterone in women: “Testosterone is related to criminal violence and aggressive dominance in prison among women, as has been reported among men.” (Psychosom Med 1997; 59: 477-80).  Even in simple “button-pushing” response tests, which can differentiate between aggressive and non-aggressive responses, “Testosterone administration resulted in a significantly higher number of aggressive responding compared to placebo.” (Drug Alcohol Depend 1995; 40: 73-9).


So, my explanation of human evolution suggests that we will often (always) form groups when the situation allows it.  That is, we will form “feed and breed” groups when conditions are propitious.  When this occurs, competition will occur.  Individuals of higher testosterone and lower cortisol will increase at the expense of lower testosterone, higher cortisol individuals.  The former will have higher sex drives and have little fear of consequences.  When we reach a state of civilization which provides for the least among us, we will first see this in ghettos.  Remember from above: “Poor motivation already in school, truancy, attention deficit and undersocialized aggressive conduct disorder seemed to be connected with the low cortisol levels.”  (Acta Psychiatr Scand 1985; 72: 40-4)  In general, in this society, better places to live are owned by people who do well in school.  People who cannot perform well in school often fall into the groups which benefit from the affluent society.  Since even the affluent society does not provide absolute equality, this will cause a concentration of high testosterone, low cortisol individuals in areas, especially within cities, that are considered less desirable.  The lower testosterone, higher cortisol individuals already there will leave.  When this occurs, an evolutionarily-programmed, aggressive “base” group will arise.  When their numbers increase beyond the ability of police to control their conduct, they will affect surrounding neighborhoods.  This has been occurring in urban areas for some time.  For years, our large, urban areas have been producing lower testosterone, higher cortisol “refugee” groups which flee their current environment for another, we call them “suburbanites.”


Now, you may be aware of the current decline in young teen birth rates.  It may seem paradoxical but this is also explained by the increase in testosterone: .


Here is the new support.


Psychoneuroendocrinology. 2006 Nov;31(10):1245-56.

Adrenal androgen and gonadal hormone levels in adolescent girls with conduct disorder.

Kathleen Pajer, et al., Columbus Children's Research Institute, Department of Pediatrics, The Ohio State University College of Medicine and Public Health, Columbus, OH, USA.

There are few data on the biological correlates of female antisocial behavior. This study compared adrenal androgen and gonadal hormone levels in adolescent girls with conduct disorder (CD) to girls without any psychiatric disorder (NC). We studied 87 girls, (47 CD; 36 NC), ages 15-17 years, obtaining three blood samples, drawn 20min apart between 8 and 9 AM in the first 72h of the onset of menstrual flow. Plasma was assayed for testosterone, estradiol, androstenedione, dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S), sex hormone binding globulin (SHBG), and cortisol; area under the curve (AUC) for each of the three samples was used in the data analysis. We also calculated the Free Testosterone Index, Free Estrogen Index, Index of Hyperandrogenism and cortisol to DHEA ratio. In addition to receiving a full psychiatric interview, each girl completed a self-report questionnaire on general aggression. Main hormone analyses controlled for potentially confounding variables such as psychiatric comorbidity and race. Girls with CD had significantly lower cortisol to DHEA ratios, but did not differ from NC girls on any other hormone variable. Girls with symptoms of aggressive CD had significantly higher mean free testosterone indexes, lower SHBG levels, and lower cortisol to DHEA ratios than girls with non-aggressive CD. Girls with CD scored higher on the aggression questionnaire, but there was no association between general aggression and any hormone variable for the sample. Our data suggest that girls with CD, particularly aggressive CD, have lower cortisol to DHEA ratios, higher levels of free testosterone, and lower levels of SHBG. Clinical and research implications of these findings are discussed.