aggression Flashcards
the limbic system - neural mechanisms
papes/maclean;
limbic sys = hypothalamus, amygdala, parts of hippocampus
reactivtiy of amygdala is import predictor of aggr
gospic et al; study where ppts subjected to mild provocation
on fmri amygdala showed heightened and fast resp when acted aggr
when taken benzodiazepine b4 provocation number of rejections halved and reduced activity of amygdala
orbitofrontal cortex and serotonin; nerual mechanisms
serotonin has inhibitory eff in brain and slows down neuronal activity
norm lev of serotonin in ofc assoc w reduced firing of neurons
reduced serotonin disrupts mechanism wh reduces self control and incr impulsive beh
virkunnen et al; compared lev serot breakdown in cerebrospinal fluid of violent impulsive and violent non impulsive offenders
lev signif lower in impulsive offend
testosterone - hormal mechanisms
responsible 4 developm of masc feat
men +re aggr than women and beco +re aggr dur developm as testo highest
testos has role in regulating social beh via influe of areas of brain implicat in aggr
giammanco et al; castration stud - removing testes of male species decr aggr
injecting w testos restores aggr
dolan et al; fou +ve correl b/w testos lev/aggr beh in 60 offend sample in uk max security hosp w men who had persoanlity disorder/history of impulsive viol
progesterone - hormonal mechanisms
lowest during/just after menst
ziomkiewicz et al; fou -ve correl b/w progest/self rep aggr
tf sugg low lev progest incr aggr in wom
ao3 - other br struct; neural mechanisms
limit
non limbic struct also involv in aggr
limbic struct funct tg w ofc wh x part limbic sys
ofc invloved impulse regulation/inhibition of aggr beh
coccaro et el; ofc act reduced in psychiatric disord feat aggr
reduced act disrupts ofcs impulse control funct wh causes aggr
tf shows that neural regulation of aggr +re complex than theories focusing on amygdala sugg
ao3 - drugs and serotonin; neural mechanisms
strength
drugs that incr serot also reduce lev aggr beh
berman et al; gave ppts either placebo/paroxetine
ppts then played lab absed game involv giving/recieving shocks in resp to provocation
parox grp consist gave fewer/less intense shocks
tf study is causal link b/w serotonin funct/aggr
ao3 - animal research; hormonal mechanisms
strength
supp fr research w animals
giammanco et al; review of study confirms role of testos
male rhesus macaque monkeys theres incr both testos lev/aggr beh in mating season
in rats, castrat of males reduces testos/mouse killing beh
injecting fem rats w testos incr mouse killing
tf findings show role testos in range anim species
ao3 - dual hormone hypothesis; hormonal mechanisms
limit
carre/menta; claimed high lev testos lead 2 aggr beh b only when lev cortisol low
wh cortisol high testos influe on aggr blocked
tf combo of testos/cortisol may be bett predictor of aggr than either hormone alone
twin studies - genetic factors
sev twin stud sugg genetic fact accounts for 50% of variance in aggr beh
coccaro et al studied MZ/DZ male twins
expect to find greater simi b/w MZ t than DZ t bc share 100% genes
res fou concordance rates of 50% 4 MZ t and 19% for DZ t
verbal agr was 28% MZ and 7% dz
adoption studies - genetic factors
simi in aggr beh b/w adopt child and biolog par sugg genetic influe operating
simi in aggr b/w adopt child and adopt par sugg environm influe
rhee/waldman; meta analysis of adopt stud of direct aggr/anti soc beh
fou genetic influe accounted for 41% variance in aggr
the MAOA gene - genetic factors
maoa reg serotonin
comes in diff variants
maoa-L res low act of maoa-A enzy
mao-L linked 2 high lev aggr beh
rod lea/chambers; show maoa-L vari possess by 56% new zealan maori men compa 34% caucasians
maori men historical warriors (warrior gene)
brunner et al stud 28 dutch family men w cr of rape, assault and all have low lev maoa-A enzy and have MAOA-L variant
gene environement interactions - genetic factors
maoa-L gene only relat to aggr wh combo w early traumatic life events
ex. frazetto et al; fou assoc b/w higher lev antisoc aggr/maoa-L in adult males b only in those who experi signif trauma dur 1st 15 yrs life
even if no trauma b have gene men x have high lev aggr
strong evid of G-E interaction
ao3 - isolating genetic factors; genetic factors
limit
diffic separat genetic/environmental factors
ie.indiv may possess gene assoc w aggr b beh only express if environm condit favourable
mcdermott et al; show ppts w maoa-L beh aggrin lab based money alloc game b only when provoked otherwise x +re/less aggr
ao3 - multiple genetic influe; genetic factors
limit
size of genetic eff stats signif b also small
probably oth genes involv
stuart et al fou intimate partner violence in men assoc w maoa-L and serotonin transporter gene combo of gene closely linked w IPV
vassos et al; in meta analysis fou no evid of assoc b/w single gene/aggr
explain 100s/1000s genes interact complex ways 2 determine aggr beh
ao3 - measuring aggr - genetic factors
limit
meth differ b/w stud inclu self rep,par/teach rep, direct obvs
rhee/waldmin; meta analysis 51 twin stud/adopt stud fou genetic influe greater in self rep studies
if vary b/w meth beco it diffic 2 draw valid conc about genetic factor role
ao3 - res supp for role of MAOA gene; genetic factors
strength
mertins et al; stud ppts w maoa low/high vari in money distrib game
ppts make decis whether contrib money 4 good of grp or x
fou male w high act maoa vari +re co op/ made fewer aggr movem than maoa-L ppts
adaptive functions of aggr - ethological explanation
aggr beneficial 2 surviv bc defeated anim rarely killed b forced 2 establish territ elsewhere
species spread out over wider area/have to discover reso in diff place wh reduc competit/starvation
male chimpanzees use aggr to climb up social hierachy
ritualistic aggr - ethological explanation
lorenz; obvs fighting b/w monkeys of same species produces little phys damage
most aggr encounters consist of prolonged period of ritualistic signalling
intra species aggr confront end w ritual appeasement signalling
indicates acceptance of defeat/inhibits furth aggr beh in victor
prev damage to loser
innate releaseing mechanisms and FAP
IRM inbuilt physiological proc/struct
environmental stim trigg IRM wh ‘releases’ specif seq beh
beh seq called FAP accord to Lea there 6 main ft
stereotyped - unchanged seq beh
unaffected by learning - same for every speci regardless of experi
universal - same beh fou every speci
ballistic - once beh trigg follows inevitable course
single purpose - beh occurs only specific situs
resp to an identifiable specific sign stimulus
timbergens research - ethological expla
proc; male sticklebacks highly territor dur spring mating seas wh develop red spot underbelly
if anoth male enters territ seq highly stereotyped aggr beh initiat
sign stim is red spot
T present stickleback w wooden models w diff shapes
findings - regardless of shape if theres red spot male stickleback displays aggr beh b x red spot then x aggr
fou aggr FAP were unchanged fr 1 encounter 2 another
once triggered always ran its course
ao3 - eval extra; ethological expla
strength
ethologists arg aggr is innate instinct
import implic is that humans will inevitably be aggr and fight each other eg in wars, Lorenz arg that this inevitablitiy is demostrated by FAPs
how oth appr sugg aggr x inevitable bc it is under rational control than instinctive
it is less innate and more affected by learning experi than ethologists accept
ao3 - culture; etholog expla
limit
aggr beh differs fr 1 cult to anoth even w/n country
nisbett fou 1 ty homicide +re common amongst white men in southern US than northern US
difference caused by culture of honour that is more prevalent in southern US
kind of aggr beh fr learned social normal than instincts
tf cult can override innate predispositions wh diffic 4 theory to expla
ao3 - ritualistic aggr; etholog expla
limit
goodwall obs 4 yr war w male chimps that killed all memb of anoth grp systematically even if shown appeasement sign
sign x inhibit aggr beh of attack
tf challenges etholog view about same species x killing each oth
ao3 - FAPs x fixed; etholog expla
limit
lorenz og FAP outdated
hunt fou FAP influe by environmental factors/learned experi
ex duration FAP varies/beh fr 1 encounter 2 anoth
ethologists now pref term ‘modal beh patterns’
tf patterns aggr beh +re flexible than lorenz thought
evolutionary explanation of sexual jealousy - evolutionary expla
jealousy occurs bc men never sure if child is theres
cuckoldry - investing in offspring x share males genes is waste of his resources and contrib 2 surviv of rivals genes w less resou 4 own offs
avoid cuckoldry = +re reproductive success
psychological mechanisms evolve ie. sexual jealousy
often these drives r aggr strateg wh men employ to retain partn
mate retention strag - evolut expla
william/daly; sev mate retent strag wh inv aggr/phys vio
1 direct guarding - inv male vigilance ov part beh
2 -ve inducement - ie using threats of conseq 4 infed
physical vio against part - evolut expla
wilson et al; ask wom 2 rep mate ret strateg in part
meas on extent to wh they agreed w statement ex know where u r
wom who agreed 2x likel 2 exp phys viol
of these wom 73% req med attent and 53% feared 4 life
supp view mate retent strateg linked phys viol
evolutionary expla of bullying - evolut expla
evolut ancest may used bullyi 2 incr surv
male bully, volk et al, arg bully charac attractive 2 wom ie dominance
bully wards off pot rivals so beh nat select bc these men wou have greater reproductive success
bully benef health bc oth avoid contact w th so x face aggr/less stress
fem bully - takes place wn relation/meth 2 control part
use bully 2 secure part fidelity wh means cont prov resou 4 fut offs, beh nat select
ao3 - gend differ, evolut expla
strength
theory expla y men/wom differ in uses of aggr
ex campbell arg that x adaptive for wom to be phys aggr bc beh risks own surv/offsps
verb aggr +re adapt to retain part so expl y fem display +re verb than phys aggr
tf arg prov supp for evolut appr
ao3 - cultural differ, evolut expla
limit
some cult aggr appears 2 be non exist
ex. !kung san peop seen ‘harmless peop’
fou -ve attit 2 aggr wh discourag fr childh in bs/gs
aggr peop status/reputat wn commun dimished
cult/soc norms constrained aggr in soc
tf since some cult x show aggr such beh x adapt
a03 - real world applic , evolut expla
strength
evolut expla can be used to reduce bullying
ellis et al sugg strat based on view that bully adapt
thru antibully interv they aim to incr costs of bully and rewards of prosocial beh
ex giving bullies responsib in skls that prov alternativ source of status
tf bully as adapt beh may lead 2 +re eff antibullying interv
ao3 - deterministic , evolut expla
evolut arg is biologically deterministic, aggr bc of adaptat that incr surviv chances of ancest so aggr inevitable and x our fault
how humanstic psych arg aggr subject to us exercising our free will, cog fact allow us to think about conseq of beh, ex cult diff
tf aggr x inevitable