Understanding and Preventing Violence, Volume 2: Biobehavioral Influences (1994)
Chapter: HUMAN DATA
has been suggested that it protects the female's developing brain from masculinization. Dixson (1980) suggests (not unreasonably) that it is important (given the variability within the order) to assess whether these relationships hold in other species of primate. Marmosets and tamarins (Callitricidae) might prove useful because of their tendency to produce twins and the possibility that sexual differentiation is delayed until after birth in such species.
HUMAN DATA
Meyer-Bahlburg (1980) and Meyer-Bahlburg and Ehrhardt (1982) comprehensively reviewed studies on the lasting impact of variations in early hormone exposure on human aggressiveness. Tables 2 through 4 provide synopses of data involving endocrine syndromes (partial androgen insensitivity and congenital adrenal hyperplasia) and treatment with hormones (generally to reduce the probability of miscarriage) created by Meyer-Bahlburg and Ehrhardt (1982). There are few reliable data on the incidences of those syndromes in particular populations (these are anyhow quite variable in their degree of severity), but their importance is not as potential causes of problems in society but as indicators of the normal biological mechanisms that influence behavioral differences between the sexes. The 5a-reductase deficiency syndrome (which is cited later) seems very rare, being associated with 38 hermaphroditic individuals born to 23 interrelated families in two inbred mountain villages in the Dominican Republic.
Although many of the data are characterized by small sample sizes, Meyer-Bahlburg (1980) suggests that exogenous sex hormones that slightly increase aggressiveness in females produce some degree of genital masculinization. He felt that the data from girls and boys resulting from treating toxemic pregnancies with progesterone were inconsistent. There was, however, some evidence of decreased aggressiveness in boys from diabetic pregnancies exposed to progestogen-estrogen combinations and from boys and girls treated with medroxyprogesterone acetate (MPA). It is, of course, uncertain precisely how such behavioral effects are generated since features such as parental rearing styles, degree of exercise, and changes in the musculoskeletal system are involved in such phenomena and are likely to be influenced (directly or indirectly) by early hormonal factors. Early exposure to androgens is said to modify temperament, increasing it in the direction of "impetuous and active." Olweus (1984) has suggested that this factor
TABLE 2 Relationships Between Aggression and Prenatal Endocrine Syndromes
TABLE 3 Associations Between Aggression and Prenatal Hormone Treatment in Females
|
Authors |
Hormone Treatment |
N |
Age (years) at Study |
Results of Assessment (by interview, unless stated otherwise) |
|
|
Ehrhardt and Money (1967) |
Various masculinizing progestins |
10 |
3.8–14.3 |
Interest in organized team sports |
|
|
|
|
Liked to compete with boys in sports |
|
||
|
|
Controls |
None |
14.3 |
Self-assertive and independent |
|
|
|
|
|
|
Self-defending and belligerent |
|
|
|
|
|
|
Aggressive attack in the pecking order |
NS? |
|
Ehrhardt (1969) |
Various masculinizing progrestins |
10 |
3.8 |
Fighting in childhood |
NS |
|
Money and Ehrhardt (1972) |
(same sample as above, reanalyzed with control group) |
|
14.3 |
|
|
|
|
Controls (pair-matched) |
10 |
3.7 |
|
|
|
|
|
|
14.3 |
|
|
|
Zussman et al. (1975, 1977) |
Progesterone |
12 |
16–19 |
Reports of discipline in school |
|
|
|
|
|
Influence over peers |
|
|
|
|
Controls |
12 |
16–19 |
Frequency and intensity of anger |
|
|
Reinisch (1981) |
Various synthetic progestins |
17 |
|
Leifer-Roberts Response Hierarchy: |
|
|
|
|
6–17 |
Potential for physical aggression |
|
|
|
|
Sibling control (at least one per hormone-exposed subject) |
17 |
|
Potential for verbal aggression |
NS |
|
Meyer-Bahlburg and Ehrhardt (1982) |
Medroxyprogesterone |
15 |
9–14 |
Self- or mother-reported aggression |
|
|
|
Pair-matched controls |
15 |
9–14 |
|
|
|
NOTE: See Table 2 for abbreviations. SOURCE: Modified from Meyer-Bahlburg and Ehrhardt (1982). |
|||||
TABLE 4 Associations Between Aggression After Prenatal Hormone Treatment in Males
|
Authors |
Hormone Treatment |
N |
Age (years) at study |
Results of Assessment (by interview, unless stated otherwise) |
|
|
|
Zussman et al. (1975, 1977) |
Progesterone |
18 |
16–19 |
Reports of discipline in school |
|
|
|
|
|
|
Influence over peers |
|
||
|
|
Controls |
17 |
16–19 |
Aggression in childhood |
|
|
|
|
|
|
|
Frequency and intensity of anger |
|
|
|
Yalom et al. (1973) |
Diethylstilbestrol + progesterone |
20 |
16–17 |
Self-rating of physical aggressiveness |
|
|
|
|
|
Clinician's ranking (aggressive-assertive) |
|
|||
|
|
Controls |
22 |
16–17 |
|
|
|
|
|
|
|
|
Moos Aggression Questionnaire |
|
|
|
|
|
|
|
|
In past week, anger at male |
|
|
|
|
|
|
|
In past week, expression anger |
|
|
|
|
|
|
|
Usually wins fights |
|
|
|
|
|
|
|
Likes to fight |
|
|
|
|
|
|
|
Number of fights |
|
|
|
|
|
|
Aggression, aggregate score |
|
|
|
|
Estradiol valerate + hydroxyprogesterone acetate |
20 |
6 |
Aggressive activity (mother's report) |
NS |
|
|
|
|
|
Clinician's ranking (aggressivity) |
NS |
||
|
|
|
|
|
Teacher's ratings: |
|
|
|
|
Controls |
17 |
6 |
|
Assertiveness |
|
|
|
|
|
|
|
Toughness |
NS |
|
|
|
|
|
|
Disruptiveness |
NS |
|
Reinisch (1981) |
Various synthetic progestins |
8 |
|
Leifer-Roberts Response Hierarchary: |
|
|
|
|
|
6–18 |
Potential for physical aggression |
|
||
|
|
Sibling controls (at least one per hormone-exposed subject) |
=8 |
|
Potential for verbal aggression |
NS |
|
|
Kester et al. (1980) |
Diethylstilbestrol |
17 |
18–30 |
Childhood: |
|
|
|
|
|
|
(a) |
Fighting |
|
|
|
|
Controls (pair-matched) |
17 |
18–30 |
(b) |
Preference for stories with more aggressive themes |
NS |
|
|
|
|
|
(c) |
Participation in individual competitive noncontact sports |
NS |
|
|
|
|
|
Adolescence: |
|
|
|
|
|
|
|
(d) |
Participation in team competitive contact sports |
NS |
|
|
|
|
|
(e) |
Participation in team competitive noncontact sports |
NS |
|
|
|
|
|
(f) |
Participation in individual competitive noncontact sports |
NS |
|
|
|
|
|
Adulthood: |
|
|
|
|
|
|
|
(g) |
Preference for TV shows with more aggressive themes |
|
|
|
|
|
|
(h) |
Participation in team competitive contact sports |
NS |
|
|
|
|
|
(i) |
Watching individual competitive contact sports |
NS |
|
|
|
|
|
(j) |
Watching team competitive contact sports |
NS |
|
|
Diethylstilbestrol, natural progesterone |
22 |
24–29 |
Childhood: |
|
|
|
|
|
|
(a) |
|
NS |
|
|
|
|
|
|
(b) |
|
NS |
|
|
|
|
|
(c) |
|
|
|
Authors |
Hormone Treatment |
N |
Age (years) at study |
Results of Assessment (by interview, unless stated otherwise) |
|
|
|
Controls (pair-matched) |
22 |
24–29 |
Adolescence: |
|
|
|
|
|
|
(d) |
NS |
|
|
|
|
|
(e) |
|
|
|
|
|
|
(f) |
NS |
|
|
|
|
|
Adulthood: |
|
|
|
|
|
|
(g) |
NS |
|
|
|
|
|
(h) |
NS |
|
|
|
|
|
(i) |
NS |
|
|
|
|
|
(j) |
NS |
|
|
Natural progesterone |
10 |
10–24 |
Childhood: |
|
|
|
|
|
|
(a) |
NS |
|
|
|
|
|
(b) |
|
|
|
|
|
|
(c) |
NS |
|
|
Controls (pair-matched) |
10 |
10–24 |
Adolescence: |
|
|
|
|
|
|
(d) |
NS |
|
|
|
|
|
(e) |
NS |
|
|
|
|
|
(f) |
NS |
|
|
|
|
|
Adulthood: |
|
|
|
|
|
|
(g) |
NS |
|
|
|
|
|
(h) |
|
|
|
|
|
|
(i) |
|
|
|
|
|
|
(k) |
NS |
