Chapter 9: Anger, Hate, Aggression Flashcards
Predatory Aggression
Usually directed at other species to obtain food
Mouse Killing by Rats
Swift, efficient, stereotyped bite to the neck
Kills immediately
No learning required
Found in a subset of males and females (individuals bring back food to the larger group)
Genetic basis for individual differences
Intermale Aggression
Within species, competition for limited resources (e.g. food, mates)
Territorial Aggression
Protecting a specific territory (land), chasing trespassers away, boundary marking
EX: scent marking (dogs)
Defensive Aggression
Defense of self, kin, territory
- Seen more in prey than predator species
Maternal Aggression
Protection of young by mother (often occurs in mammals)
- Highest when individuals still nursing, or when high investment in their offspring (k-selected species)
Irritable Aggression
Induced by frustration or pain
Shock-Induced Fighting
Observed in mice and rats
Observed in both males and females
When two individuals are housed together and given repeated foot-shocks, they often fight
The probability of fighting response increases with increasing shock duration, which is indicative of increasing frustration
Instrumental Aggression
Learned and developed via conditioning, influenced by rewards
Threat
Self-maximizing postures (max size–stand tall/large, fur stand up)
Angry facial expressions (hate stare)
Angry vocal expressions (barking)
Appeasement
Self-minimizing postures
Withdrawal
Female sexual postures
Species-specific gestures
Infanticide (males)
Direct aggression to offspring sired by another male
- Estrous cycle will not begin again until nursing has stopped
- Once nursing stops, opportunity to mate
Occurs in many mammalian species
Often due to intermale competition
Infanticide (females)
Direct aggression to their own young
- Usually early in the infant’s life (less attachment, less resources used yet)
Occurs in many mammalian species
Often due to lack of resources and support
Also due to weak or defective offspring
Sex Differences in Aggression
Males are usually more aggressive than females (reflected in rough/tumble play)
Individuals are most likely to attack non-genetic kin
- Cinderella effect: stepchildren experience abuse more than biological
- Homicides greater among males, higher rate of offending in males
Androgens and Aggression
Perinatal and pubertal testosterone correlate with higher levels of aggression in many species
(red deer, elephants, cats, mice, rats, etc)
Castration reduces or eliminates intermale aggression in many species
Female mice injected with testosterone perinatally and throughout adulthood show male levels of aggression
Aggression in Red Deer
Aggressive behaviours in red deer is tightly linked to peak circulating levels of testosterone and maximal antler growth, which occur during mating season in late November
- Have 1 male having many offspring, and other males have none (extreme reproductive success)
Aggression in House Mice
Occurs spontaneously, without learning
Males direct aggression towards other males (to extreme injury/death)
Competition for females intensifies aggression
Females usually only fight in defense
Stereotyped actions: Tail rattle, flank and hindquarter bites
- 2M females have higher interfemale aggression than 0M females
Rhesus Macaques & testosterone levels
Dominant monkeys within stable groups show high testosterone levels (mate/fight the most)
Subordinate monkeys within stable groups show low testosterone levels
Dominant monkeys moved to a new group show decreased testosterone levels
Affective Attack
“Halloween-cat” posture, screams, erect fur, arched back, exposed teeth
Induced by stimulating the medial hypothalamus
Observed in cats, rats, opossums, monkeys
Quiet Biting Attack
No emotion
Searching for prey, pouncing on prey with powerful bites to the head and neck
Induced by stimulating the lateral hypothalamus
Observed in cats, rats, opossums, monkeys
Amygdala Damage
Damaging parts of the amygdala can lead to tameness and placidity, whereas other parts can lead to an increase in aggression
Does not just change emotion
Changes how animals interpret information, especially social signals (facial cues)
Animals may be attacked or inappropriately attack others
Male cats will mount indiscriminately
10% of human temporal lobe epilepsy cases have occasional uncontrollable outbursts of rage
Tumours in this area can also induce rage behaviour
Catecholamines and Aggression
Natural brain catecholamines (dopamine and norepinephrine) are very active during aggressive encounters in mice
Drugs like amphetamine increase aggressiveness at moderate doses
Siegel et el (1974)
electrical stimulation of prefrontal cortex
Prefrontal cortex regulates aggressive behaviour
Electrical stimulation of prefrontal cortex suppresses affective attack & quiet biting attack, but not flight responses (Observed in cats)
Best et al (2002)
damage to prefrontal cortex & IED
Human individuals w damage to prefrontal cortex display impulsive aggressive behaviour
Perform poorly on several tasks that assess prefrontal cortex capabilities: Facial emotion recognition, Iowa gambling task, Odour identification
Patients diagnosed w intermittent explosive disorder display impulsive aggressive behaviour
Perform similarly to individuals w prefrontal cortex damage on these tasks
Suggests a link b/w prefrontal cortex dysfunction and aggression
- IED patients do not learn to avoid disadvantage decks
- IED patients make more errors labelling emotions and more likely to label neutral faces
