Genetic factors in aggression Flashcards
Cesare Lombroso
claimed sloping foreheads, jutting chins and long arms were genetic features of born criminals
Ardrey
claimed “man is a predator whose natural instinct is to kill with a weapon”
Lacks scientific proof
Sandberg
most individuals have 46-xy karyotype gene
1 man in every 1000 has an extra y so 47-xyy karyotype
extra y makes someone more masculine - aggressive
Richard Speck
killed 8 student nurses in attempt to obtain leniency
Nielson
claimed number of XYY men in prison was 60 times higher than general population
only identified 2 criminals with XYY gene
Nanko
47-XYY + 47-XXY male Japanese juveniles
test show XYY were more aggressive
Gotz
34000 infants screened at birth, comparing XYY with matched controls
higher frequency of antisocial behaviour in XYY (adulthood and childhood)
Briken
meta analysis court reports of 166 murderers (German)
3/13 (1.8%) had XYY
1.8% murderers compared to 0.01% general population
Brunner et al
family with males with violent and aggressive behaviour
low levels of MAOA so serotonin and noradrenaline levels were high
Cases et al and Popova et al
mice with altered MAOA gene showed high levels of aggression and serotonin and noradrenaline
Manuck et al
110 men who had an abnormal MAOA gene
higher levels of noradrenaline, prone to aggression
Caspi et al
398 males (New Zealand) screened for MAOA gene longitudinal study - behaviour was studied 16-30yrs low levels of MAOA = antisocial and aggressive
Hudziak et al
personality characteristics and behaviours linked to aggression have greater concordance in MZ twins compared to DZ twins
Rhee and Waldman
meta analysis of twins and adoption studies
estimated genetic influences are the cause of 41% of the variability in antisocial behaviour
Guo et al
claimed we could be hard wired for aggression in order to cope with social and ecological demands of the environment
those better equipped will pass gene to next generation
lead to people saying they’re not responsible for their actions
