Biological Theories Flashcards
L1
Darwin proposed two processes through which evolution occurs:
1: Survive through to reproductive age
2: To reproduce
Darwin proposed that we develop characteristics to help us survive - AKA…
…adaptations
What are the 2 basic principles of evolutionary theory?
1: Natural selection
2: Sexual selection
Natural Selection
What are the 2 basic principles of evolutionary theory?
- A process through which organisms develop characteristics or adaptations that enhance their ability to survive
- Higher survival rate = more likely to live to reproductive age and pass these characteristics on to the next generation
Across successive generations, what happens to the adapted “survival-enhancing” characteristics?
What are the 2 basic principles of evolutionary theory?
increase in frequency until they characterize most members of the species
Sexual selection
What are the 2 basic principles of evolutionary theory?
A process through which organisms develop characteristics that enhance their ability to reproduce
Darwin proposed two mechanisms through which sexual selection occurs:
What are the 2 basic principles of evolutionary theory?
(a) Intrasexual selection (i.e., same-sex competition)
(b) Intersexual selection
(a) Intrasexual selection
- Occurs when same sex organisms compete for the sexual interest of the opposite sex
- Organisms who possess characteristics that enable them to “win” the sexual interest of the opposite sex are more likely to mate and pass these characteristics on to the next generation
- Across successive generations, the “winning” characteristics increase in frequency until they characterize most members of that sex of the species
(b) Intersexual selection
- Occurs when organisms of one sex prefer to mate with organisms of the opposite sex who possess specific, desirable characteristics
- Offspring who inherit these characteristics are more likely to mate and pass the characteristics on to yet the next generation
- Across successive generations, the desirable characteristics increase in frequency until they characterize most members of that sex of the species
Evolutionary psychologists believe that our psychological processes are the product of WHAT?
How have the basic principles of evolutionary theory been adapted to the study of personality?
natural selection and sexual selection
How are psychological processes interpreted?
How have the basic principles of evolutionary theory been adapted to the study of personality?
Psychological processes are seen as adaptations to the survival and reproductive challenges faced by our ancestor
With respect to personality, evolutionary psychologists have focused the bulk of their research on…
…sex differences (vs. human universals and individual differences)
- Evolutionary research on sex differences in personality is premised on sex differences in reproductive capacity and minimal parental investment
Reproductive capacity:
Gender comparison
- Males > Females
- Females: 8 – 12 offspring across the lifespan
- Males: An almost unlimited number of offspring across the lifespan (maximum recorded to date: 900)
Minimal parental investment:
Gender comparison
- Females > Males
- Females: Carry and nourish fetus for 9 months; nurse child after birth; during lactation, ovulation is suppressed
- Males: Engage in copulation
HYPOTHESIS A - Given sex differences in reproductive capacity and minimal parental investment, what can we conclude about mate preferences?
- …sex differences have evolved in mate preferences:
- Males: value appearance in a mate more than female; an indicator of how well a female could produce “healthy” offspring
- Females value resource potential in a mate more than male
HYPOTHESIS B - Given sex differences in reproductive capacity and minimal parental investment, what can we conclude about sociosexuality?
Males are higher in sociosexuality (e.g., seek more sexual partners, are less discriminating in choice of sexual partners) than females
Criticisms of evolutionary psychology
Despite the influence of evolutionary psychology, theorists critique it as:
* Unfalsifiable
* We’re not able to test the validity of such claims about our original/advanced characteristics
* Controversial (e.g., Cinderella effect, heteronormative, heterosexist)
L2
What are the goals of behavioural genetics?
1: determine the degree to which individual differences and personality characteristics within a population are caused by genetic factors versus environmental factors
2: identify genetic factors that contribute to individual differences in personality characteristics
3: to identify environmental factors that contribute to individual differences in personality characteristics
Vp = Vg + Ve: What do each stand for?
1: determine the degree to which individual differences and personality characteristics within a population are caused by genetic factors versus environmental factors
Vp = Variation in a personality characteristic within a population
Vg = Variation in the genetic factors that contribute to that characteristic
Ve = Variations in the environment factors that contribute to the characteristic
Behavioural genetics cannot be applied to individuals due to 3 genotype-environment correlations:
1: determine the degree to which individual differences and personality characteristics within a population are caused by genetic factors versus environmental factors
1: Passive genotype environment correlation
2: Reactive genotype-environment correlation
3: Active genotype-environment correlation (niche picking)
Passive genotype environment correlation
Behavioural genetics cannot be applied to individuals due to 3 genotype-environment correlations:
occurs when parents passively provide a gene-conductive environment to their children, encouraging the expression of their children’s genetic predispositions
Reactive genotype-environment correlation
Behavioural genetics cannot be applied to individuals due to 3 genotype-environment correlations:
occurs when parents actively provide a gene-conductive environment to their children, encouraging the expression of their children’s genetic predispositions
Active genotype-environment correlation (niche picking)
Behavioural genetics cannot be applied to individuals due to 3 genotype-environment correlations:
occurs when individuals with a genotype create or seek out gene-conductive environments, encouraging the expression of their own genetic predispositions
EXAMPLE
2: identify genetic factors that contribute to individual differences in personality characteristics
- EX: Gene D4DR on chromosome 11 contributes to individual differences in sensation seeking
- Linked to dopamine receptors, “feel good” neurotransmitter
EXAMPLE
3: to identify environmental factors that contribute to individual differences in personality characteristics
EX: non-shared environmental influences have greater influence than shared environmental influences on the personalities of siblings
Heritability
What are heritability and environmentality and how are they assessed?
proportion of phenotypic variance that is attributable to genotype variance
Heritability - phenotype variance:
What are heritability and environmentality and how are they assessed?
individual difference sin an observable characteristic
Heritability - genotype variance:
What are heritability and environmentality and how are they assessed?
individual differences in genetic makeup
Environmentality
What are heritability and environmentality and how are they assessed?
proportion of phenotypic variance that is attributable to variance in environmental factors
What are 2 ways that heritability and environmentality assessed?
1: Adoption studies
2: Twin studies
Adoption studies
Heritability and environmentality assessments
contrast adopted children to their biological parents and adoptive parents on a characteristic of interest
Adoption studies - assess 2 correlations:
Heritability and environmentality assessments
- r1: correlation between adopted children’s scores and the scores of their biological parents on the characteristic (influence of shared genes)
- r2: correlation between adopted children’s scores and the scores of their adoptive parents on the characteristic
Adoption studies - relation between r1 and r2: what indicates that a characteristic is heritable?
Heritability and environmentality assessments
r1 > r2 indicates that the personality characteristic is heritable
Criticism of adoption studies
Heritability and environmentality assessments
adoption studies do not correct for “selective placement” (i.e. the possibility that adopted children are placed with adoptive parents who are genetically similar to their biological parents - like Filipino with Filipino)
Twin studies:
Monozygotic vs. dizygotic
Heritability and environmentality assessments
- Contrast monozygotic twins to dizygotic twins on a characteristic of interest
- MZ twins share 100% of their genes; DZ twins their 50% of their genes
- More powerful than adoption studies
Twin studies - assess 2 correlations:
Heritability and environmentality assessments
- r1:correlation between MZ twins on characteristic (large degree of genetic overlap)
- r2: correlation between DZ twins on characteristic (small degree of genetic overlap)
- r1 > r2 indicates that the characteristic is heritable
Heritability equation
Heritability and environmentality assessments
Heritability = 2 (r1 - r2)
Environmentality equation
Heritability and environmentality assessments
Environmentality = (1.00 -heritability)
Criticism of twin studies
Heritability and environmentality assessments
twin studies do not correct for the equal environments assumption (ie, that they assume that MZ twins are not treated any more similarly than DZ twins)
Heritability of dimensions of the five-factor taxonomy
What personality characteristics are heritable?
- O: .57
- C: .49
- A: .42
- E: .54
- N: .48
Heritability of temperments:
Appear during the 1st year of life, persist across the lifespan, have a pervasive influence on behaviour, are highly heritable
Heritability of temperments - 3 mentioned:
- Activity level: degree to which an individual expends physical energy through motor activity
- Emotionality: degree to which an individual becomes physiologically aroused (anger, distress, fear) in upsetting situations
- Sociability: degree to which an individual prefers to be with others rather than alone
Heritability of personality disorders (6)
- Antisocial: .69
- Avoidant: .67
- Borderline: .67
- Narcissistic: .71
- Obsessive-compulsive: .53
- Schizotypal: .72
Heritability of characteristics associated with psychopathy:
- Blame externalization: 82
- Carefree nonplanfulness: .94
- Coldheartedness: >.99
- Fearlessness: >.99
- Impulsive non-conformity: >.99
- Machiavellianism: .74
- Social potency: .66
- Stress immunity: >.99
Are personality characteristics heritable?
All personability characteristics studied to date show some degree of heritability; most characteristics have a heritability between 0.40 and 0.6
L3
What does contemporary research suggest about the physiological basis of a) extraversion? - LEADING RESEARCHER
Eysenck
How did Eysenck explain the physiological basis of extraversion?
Eysenck implicated the ascending reticular activating system (ARAS) in individual differences in extraversion
- ARAS: a group of nuclei in brainstem that receive sensory information from our bodies, serve as a sensory relay to different parts of the brain/body - specifically cerebral cortex; directing our muscles to respond to stimuli
ARAS - gateway analogy
When open, nervous stimulation is being relayed to the cerebral cortex
* High ARAS activity = high cortical arousal
When closed, nervous stimulation is not transmitting/relaying to the cerebral cortex
* Low ARAS activity = low cortical arousal
ARAS activity for introverts
- Eysenck argued that introverts have relatively high ARAS activity and, consequently, high cortical arousal
- In order to avoid further arousal, introverts restrain themselves, seek low stimulation settings, and avoid social interactions
- Hyperactivity in cortex, thus seeking to de-regulate, introverts engage in activities that regulate their arousal downward
ARAS activity for extraverts
- Eysenck argued that extraverts have relatively low ARAS activity and, consequently, low cortical arousal (below the optimal level)
- In order to enhance their arousal, extraverts seek stimulation experiences, settings, and social interactions
Lessened activity in cortex, seeking to up-regulate
What does contemporary research suggest about the physiological basis of b) sensitivity to reward and punishment? - LEADING RESEARCHER
Gray
Gray implicated two physiological systems in individual differences in sensitivity to reward and punishment (hypothetical)
- Behavioural activation system (BAS)
- Behavioural inhibition system (BIS)
Behavioural activation system (BAS)
Location, related neurotransmitters, responsiveness, associations
- Left prefrontal cortex (linked to experiencing positive emotions)
- Linked to dopamine (“motivation, feel good” neurotransmitter): high levels
- Responsive to rewards or incentives, generates positive emotions, and regulate “approach” behaviour
- Association with individual differences in extraversion
Behavioural inhibition system (BIS)
Location, related neurotransmitters, responsiveness, associations
- Right prefrontal cortex
- Linked to serotonin, GABA, and norepinephrine
- Responsive to punishment or frustration, generates negative emotions, and regulates avoidance behaviour
- EX: stopping activity as a kid when getting a stern look from parents
- Associated with individual differences in neuroticism
How can the BAS/BIS be scored?
Test - BAS/BIS sensitivity survey
How would you expect the BAS and BIS to influence learning?
- Those with sensitive BIS tend to learn better when punished
- Those with sensitive BAS tend to learn better when encouraged
What is sensation seeking (ss)?
What does contemporary research suggest about the physiological basis of c) sensation seeking
refers to the tendency to seek novel experiences that are both exciting and risky
SS is associated with…
experience/adventure/thrill seeking, disinhibition, and boredom susceptibility
How can SS be tested?
the SS scale
How did Zuckerman implicate individual differences in SS
- Zuckerman implicated monoamine oxidase in individual differences in SS
- MAO breaks down neurotransmitters + affects neurotransmission
- Acts as a “brake”
- Sensation seekers have relatively low MAO, resulting in relatively high neurotransmission of dopamine
- High dopamine, in turn, causes “disinhibition” of the nervous system
