Class Notes (836,219)
Canada (509,690)
Biochemistry (232)
Lecture

October 29 Class Notes (Week 10 Aggression, Anger) - Chapter 9 - PSYCH 3M03
Premium

5 Pages
64 Views
Unlock Document

Department
Biochemistry
Course
BIOCHEM 2B03
Professor
Denys Decatanzaro
Semester
Fall

Description
WEEK 10 PSYCH 3M03 Chapter 9: Anger, Hate and Aggression October 24, 25, 2013  Threat – shows intention to follow through with aggression, could be bluffing  Rage – amygdala and hypothalamus o Baring of the teeth o Social animals do not have musculature to show certain facial expressions  Fear – most ancient in terms of evolutionary conservation; conserved neural circuits in hypothalamus, amygdala and autonomic responses  Aggression – fighting; beyond threat; same sort of fighting across mammals (use of the teeth, ramming of head, boxing) o Sexually dimorphic – rats, humans, vertebrates  more among males  Forms of Aggression o Predatory aggression – usually directed at other species to obtain food  Motivation – food; usually another species, cannibalism can occur o Intermale Aggression – within species, competing for limited resources (eg/ food, mates)  Related to territorial aggression – each have own dynamic, but interrelated with overlap  Polygyny common among mammals sets the stage for differential and reproductive success amongst males; differential is established by threat and aggression  Males being chased away from harems of females by another male (baboons, rhesus monkeys, gorillas etc)  Accounts for evolution of intermale aggression – aggression against other males leads to gains in reproduction and characteristic gets propagated o Territorial Aggression – protecting specific territory, chasing trespassers away, boundary marking  Same type of dynamic as intermale aggression – often males hold territories and fend off intruders o Defensive Aggression – defense of self, kin, territory  Females and males  If attacked by a male, female will show whole range of aggressive behaviour in defense  Will attack in defense of kin o Maternal Aggression – protection of young by mother o Irritable Aggression – induced by frustration or pain  At least anger will be shown by frustration (non-reward; reward expected but do not receive it) o Instrumental Aggression – dispassionate, learned, developed via conditioning, influenced by rewards  Neurologically, behaviorally complex; intelligent  Elicited by passion, occurs view calculated aggression  Eg/ if I kill, I will get a reward  Dominance and Subordination o Dominance is associated with controlling resources and/or hierarchal control within a group o Results from competitive interactions that are aggressive in nature or threatening o Threat and appeasement are more common than outright violence  Threat gestures – posture, angry facial expression, barking, “hate stares”, rushing, self maximizing postures (eg/ piloerection maximizes appearance)  Appeasement – self minimizing postures, withdrawal, female sexual postures, species-specific gestures (eg/ exposure of neck in wolves, smiling in humans)  Subordinate males may begin starting sexual postures (eg/ in baboons) o Alpha males that are polygynous – other keep respective distance or may give them things to appease them o Non-alpha males are usually excluded from the group o Eg/ Gorillas - ~3 males and 6-7 females; one alpha male who mates frequently, other males do not mate, waiting for alpha male to die; juvenile male and females; all other adult males have been excluded o Less stressful to be subordinate o Dominance is situation specific – alpha male may not always be alpha male  Sex Differences in Aggression o Males are usually more aggressive than females  Eg/ bulls vs. cows; stallions vs. mares  Seen in humans beings; seen in juveniles across species (developing boys demonstrate play fighting) o This is seen in mammalian species including humans o Reflected in rough and tumble play in children o Testosterone perinatally and at puberty correlated with higher levels of aggression in many species (eg/ red deer, elephants, cats, mice, rats etc) o Castration will reduce or even eliminate intermale aggression in many species (eg/ cats, rats, mice, horses, cattle) o Female mice injected with testosterone perinatally and given repeated doses through adulthood  male levels of aggression 1 WEEK 10 PSYCH 3M03  Humans o Connection between testosterone levels and human aggression is not clear o Aggression in boys does not consistently change at puberty o Individuals can have very high T but not be aggressive, or low levels and be aggressive o T related more to social dominance than aggression o Sex and Age of Homicide Victims  Canada  Victims of homicide ages and sex  More commonly male victims  Peak around most reproductive years – not including infants o Infants often killed by mother or other males (more often not the father; may be male with relations to the mother who is not the father)  Mexico  Differential between males and females Trend more stark than Canada  More commonly male victims  Illustrates male vs. male aggression Physiology and Aggression  Rage, fear, excitement – autonomic nervous system; intense activation of sympathetic NS; blood pressure, respiratory rate, flow of blood to the muscles and brain o Anger and fear have some differences – paleness in fear (blood draining from face), flushing in anger o Central catecholamine’s in aggression o Prepare for alertness and full body activation o Less so with sadness, embarrassment  Sex, Androgens and Aggression o Males generally more aggressive than females in many mammals, including humans  In human cultures, there are some pressures that take us away from evolutionary roots – eg/ bullies don’t always get ahead because it is not necessarily socially acceptable o Reflected in rough and tumble play in juveniles; boys vs. girls  NOT a simple case of more androgens more aggressive and sexual behaviour – threshold level is necessary for male sexuality and aggression to occur o T perinatally and adulthood related to aggression in many species (eg/ red deer, cats, mice, rats etc)  Critical period during perinatal development in which brain differentiates (preoptic areas particularly for sexuality and aggression; anterior hypothalamus) for behaviorally masculinity; surge in androgens as gonads develop that causes differentiation of critical areas of hypothalamus; endured throughout life  Give androgens to female mouse perinatally – morphologically female; reaches adulthood and regularly inject testosterone  more aggression o Castration will reduce or even eliminate intermale aggression in many species  Testosterone sustained above threshold is needed for aggression and sexual behaviour  Eg/ in cat, cattle, rats, mice, horses; less so in dogs  Castration inhibits post-pubertal aggression – androgen levels below threshold  Inject testosterone back into castrated male – can restore aggression to regular level o Female mice injected with T perinatally and throughout adulthood show male levels of aggression o 2 factors – presence of absence of perinatal surge and sustained levels above critical threshold post-pubertally  Eg/ Red Deer Intermale Aggression – reproduction is seasonal; gonads regress during non-reproductive seasons; males developing antlers and surge of testosterone above threshold (because of suppression the rest of the year) during rut, seeking to breed and competing with other males (polygynous species) o High correlation between testosterone levels, antler growth, aggressiveness  Aggression in House Mice o Best studied, typical results in other animals; confidence because primitive mammal o Males direct aggression vs. males o Females usually only fight in defense o Genetic o Perinatal development o Stereotyped patterns (FAP) – tail-rattle, flank and hind quarter bites o Spontaneous and without learning  Eg/ Mice – Raise in isolation, no exposure; put two mice together; will start fighting o Competition for females intensified intermale aggression  Competition for reproductive success – possibly the root of intermale aggression is reproductive success  Hormonal Response to Aggression in Mice o LH + T decline following defeat; increases in success (short term; within minutes, hours) 2 WEEK 10 PSYCH 3M03 o Defeated males show diminished gonadal and enhanced adrenal response (long term)  Depression o Central catecholamine’s dynamic in aggression become depleted following defeat and enhanced following victory  Increases in victorious – have not yet reached point of exhaustion  Social Status o Male Mice Winners Losers Aggression Increased Decreased Assertiveness Increased Decreased Sexual Activity Increased Decreased Catecholamine’s Increased Decreased Testes Increased Decreased Adrenals Decreased Increased  Victorious in aggression, become more aggressive; defeated individuals decrease in aggressiveness (become more cautious)  Ex/ even if no other male present, sexually defeated males may not even att
More Less

Related notes for BIOCHEM 2B03

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit