1. Aggression Most psychologists define aggression as behavior with intent to harm or injure.

2. Maccoby & Jacklin. “Fairly well-established gender. difference”
Maccoby & Jacklin “Fairly well-established gender difference” - For both physical and verbal aggressio - Across cultures - Appeared between 2 and 3 yrs old and continued through college - After that little information available

3. Janet Hyde – 5% of differences can be attributed to gender
Age 6 – 7% of variance
College Age – 1% of variance

4. Sex Differences in US Crime Statistics

5. Aggression in Pre-School Children

6. Biological Explanations
Testosterone levels
Pre-natal hormones
Serotonin

7. Mice data

8. More Rat data

9. Bird data

10. Human data – Correlation Studies

11. No Correlation – Some studies on men have shown this kind of relationship

12. Correlation studies in Men
High Testosterone levels have been correlated with:
- History of arrests 2 studies
- History of violent crimes 1 study
- Less likely to marry, more to
divorce, troubled relations 1 study
- Aggressive disposition 2 studies
- variety of anti-social behavior
AWOL, alcohol & drug abuse 1 study

13. CAH Girls Activity Level

14. Serotonin Levels in Violent Suicides

15. Serotonin Reuptake Inhibitor

16. Stereotypes
Play

17. Acceptable Male behavior

19. Big Boys Toys

20. Movies

21. Video Games

22. Sports Images

23. International Problem Solving