Psych 203 Chapter 6&7
Behavioral genetics
A branch of genetics that studies how heredity and the environment create personality Main assumption = observable personality characteristics are phenotypic expressions of a person's genotype interacting with his or her environment Phenotype = outward appearance; a person's observable features and behaviors
Genetic similarity theory
A gene is represented in the next generation by anything that brings about reproduction of any organism in which copies of the gene exist you're more attracted to strangers who resemble you genetically than those who don't
Bipolar disorder
A second disorder that appears to be affected by heredity is bipolar disorder. Mania is characterized by episodes of frenetic, hyperactive, grandiose, and talkative behavior, accompanied by a rush of ideas. Often the manic pattern is accompanied by positive emotion, but anger is also common. The onset of this disorder is usually sudden Events in the environment are important to how the disorder is expressed -- ex. Lack of sleep, experiencing success in attaining goals
How do situations differ for people with different genes?
A situation might cause one reaction in a person with one genetic makeup and a different reaction in a person with a different genetic makeup
Left prefrontal cortex
A variety of evidence suggests that incentives (and positive feelings) activate areas in the left prefrontal cortex. More left-prefrontal activity has been found in adults presented with incentives, or positive emotional adjectives Higher resting levels in this area predict positive responses to happy films and to greater effort in pursuit of rewards
Three dimensions of individual differences in personality deserve to be called temperaments
Activity level -- Person's output of energy of behavior; Has two highly correlated aspects: vigor (the intensity of behavior) and tempo (its speed) Sociability -- Tendency to prefer being with other people, rather than alone Emotionality -- Tendency to become emotionally aroused - easily and intensely - in upsetting situations
Gamma-aminobutyric acid (GABA)
Another candidate for involvement in anxiety Some research linking sensitivity of GABA receptors to neuroticism People with panic disorder have relatively low levels of GABA Treatments that increase GABA reduce the symptoms of panic patients
Role of sociability
As noted earlier in the chapter, however, some theorists think there's a separate approach subsystem that's specialized to regulate social approach. Perhaps extraversion actually is a blend of overall BAS sensitivity and social-specific BAS sensitivity one project concluded that the core of extraversion is reward sensitivity and the tendency to experience positive affect. Lucas and Diener (2001) found extraverts were drawn to situations that offered opportunities for rewarding experiences, whether social or nonsocial. Other research has shown that extraverts are not more responsive to pleasant stimuli in general, but only to appetitive stimuli—those associated with approach motivation and reward
Proteins
Chains of amino acids in a certain order Sequence of amino acid chains is specified by the DNA molecule Proteins underlie all aspects of human functioning --Structural proteins produce our bodies; Functional proteins regulate chemical reactions in the body
Amino acids
Chemical compounds made of nitrogen, hydrogen, carbon, and oxygen Human body uses 20, and they all have the same form, except for one part If that one part was a single hydrogen atom, the amino acid is glycine (GLY)
Five-factors/five dimensions are genetically influenced
Decrease over the lifespan Evidence of an invariant genetic influence on the five factors across cultures Five factors have considerable conceptual similarity to the temperaments
Another determinant of impulse and restraint
Effortful control has an influence over both approach and avoidance -- Helps people hold back from doing something they want to do; Helps people do things they don't want to do; These influences on behavior need not involve fear at all
Neuroticism and threat sensitivity have a great deal in common
Evidence that the brain areas believed to be important in threat responses covary in volume with neuroticism
Androgen sources
Exposure through a mother's medical treatment during pregnancy Adrenal glands, which secrete androgen
Environmental effects on gene expression
Genes render some people more susceptible than others to environmental influences Environments affect genes ability to function Gene expression = when the gene engages in the processes that create a protein; varies by region and type of cell involved
Sources of variance
Heredity (variations of gene) Shared environmental variance (factors that promote family similarity) Nonshared environmental variance (factors that promote family dissimilarity) Error
Nature vs. nurture
How do heredity (nature) and upbringing (nurture) combine to create personality Nature sets an upper limit on what nurture can produce
Relating sensation seeking to traits and temperaments
IUSS relates inversely to both agreeableness and conscientiousness of the five-factor model and to constraint from Tellegen's model -- low levels of these traits relate to problems in getting along in life. IUSS also relates to psychoticism in Eysenck's model, which concerns disregard of social restraint in pursuit of intense sensations The temperament called effortful control bears a good deal of resemblance to IUSS. It's about being focused and restrained, and it implies planfulness and awareness of others' needs. High levels of this temperament early in life predict fewer problems with antisocial behavior later on -- This temperament is slower to emerge than the approach and avoidance temperaments and may not be fully operative until adulthood; It's believed to relate to the part of the brain that manages executive functions: the prefrontal cortex
Competition for mates
If men are interested in finding fertile partners, women should compete by stressing attributes that relate to fertility—youth and beauty If women want to find partners who will provide for them and their babies, men should compete by stressing their status, dominance and ambition, and wealth or potential for wealth Prime basis for jealousy in females is a partner's emotional attachment to another and in male's it is a partner's sexual-infidelity
Parent-child interactions
Interpretive effects -- Anxious children interpret their parent's behavior differently than do calm children Selective effects --Parents select different environments for anxious children than for calm ones Evoked effects -- Anxious children evoke different parenting behaviors than do calm children
Eysenck's early views on brain functions
Introverts are quiet and retiring; extraverts are outgoing, uninhibited, and immersed in social activity. Eysenck (1967, 1981) argued that this difference derives from differences in activation of the cerebral cortex. When the cortex is activated, the person is alert. When it's not, the person is drowsy. Eysenck proposed that introverts normally have higher cortical arousal than extraverts. This leads them to avoid social interaction, because it gets them overstimulated. Extraverts, with lower baseline levels, seek stimulation to bring their arousal up
Norepinephrine
Likely contributor to the biology of threat Produced in response to stress Linked to panic reactions Problems in regulating norepinephrine relate selectively to anxiety disorders
Zuckerman (1994, 1995) suggested a role for monoamine oxidase (MAO), which helps regulate several neurotransmitters
MAO levels relate to personality traits such as sensation seeking and novelty seeking; also relates to dominance, aggression and drunk driving Genes related to MAO levels have been linked to aggression and impulsivity On the other hand, some researchers consider MAO level to be mostly an indicator of the activity of neurons of the serotonin system - perhaps the key actually lies in serotonin function
Suggested that evolutionary differences cause men and women to have very different styles -indeed different needs—in communication
Men are seen as having an individualistic, dominance-oriented, problem-solving approach Women are seen as having an inclusive, sharing, communal approach
Gene expression is influenced by several factors that affect the gene's accessibility to other chemicals
Methylation = the attachment of methyl chemical groups to what's called the gene's promoter region (it's "on" switch) -- When there's more methylation, there's less gene expression; Called epigenetic because it doesn't involve a change in the gene itself; Can be affected by stress level and even by diet Epigenetic changes can be passed from one generation to the next, just as genetic influences are passed onward
Nonshared environmental factors
Most of the nongenetic variance is predicted by nonshared environmental variance Growing up in the same family environment doesn't make people's personality similar Differences in the ways parents treat their children matter more than similarities Personality is not the same as character. Family resemblance is stronger for traits that tap moral behaviors, such as honesty and generosity
Testosterone and adult personality
Not only can having low SES (socioeconomic status) increase the ill effects of high testosterone, but high testosterone tends to lead men into lower-SES lives. This seems to occur because high testosterone promotes antisocial behavior and disruption of education. Both factors then lead people away from white-collar occupations High testosterone can interfere with relationships -- Men high in testosterone were less likely to be married, and if they did marry they were more likely to divorce a factor formed around testosterone, with overtones of impulsiveness, sensation seeking, and dominance. The factor included these self-ratings: cynical, dominant, sarcastic, spontaneous, persistent, and uninhibited
Problem with biological therapies
One issue concerns the fact that responses to the medications often are much broader than the mere lifting of a depressed mood. People's personalities undergo changes that are subtle but profound and pervasive. People become more confident, more resilient, more decisive—almost more dominant—than they were before. In a sense, they aren't quite the same people as they were before taking the medication. Their very personalities have changed
Sensation seeking
One more broad biologically based dimension of personality Incorporated a quality of planfulness vs. impulsivity Want new, varied, and exciting experiences Ex. Faster drivers, more likely to use drugs, to increase alcohol use over time, etc
How do people detect genetic similarity in others?
One possibility is that we are drawn to others who share our facial and body features Another possibility is that genetic similarity is conveyed by smell
Evocative parenting of twins
Parents treat MZ twins more similarly than DZ twins Effect occurs among misdiagnosed twins, too, suggesting the similarities are evoked by the children An adoptive parent's parenting style can be predicted from the biological parent's personality
Functional MRI
People are being studied to assess levels of activation in various brain regions, both at rest and when engaged in tasks much more detailed than what comes from EEG recordings. Of particular importance is that it lets the brain be viewed in slices at different levels. The result is a very detailed three-dimensional picture about what brain centers are active during the scan
Eysenck's neural basis for neuroticism
People who are high on this trait have easily aroused emotion centers. He thought this emotional arousal intensifies the manifestations of both extraversion and introversion—that is, it causes both to emerge more fully in behavior. This arousal causes both extraverts and introverts to become "more of what they are
What underlies left-prefrontal activation?
Recent evidence suggests that what underlies left-prefrontal activation is the approach process itself, rather than the positive feelings This evidence suggests that the core of left-frontal activation is the desire for reward, whether you're just about to get it (and you're happy) or whether someone has taken it away from you (and you're angry)
Substance use
Recent research has also implicated a specific polymorphism in the craving for alcohol that some people experience after having a small amount turns out to be the long allele of the DRD4 gene that was described earlier in the chapter—the gene that relates to measures of reward seeking. That allele has also been linked to the creation of stronger social bonds while drinking alcohol; also been linked to heroin addiction Another dopamine-related gene, ANKK1, has also been linked to attention deficit disorder and substance abuse
Electroencephalograms (EEG)
Recording electrical activity from the scalp gives indirect indication of brain activity reason behind EEG is that neurons in the brain fire at various intervals, creating fluctuations in voltage. Electrodes on the scalp sense these changes, giving a view of aspects of the activity in the cerebral cortex. Cortical activity is very complex, but it forms patterns that relate to different subjective states Various regions of the cortex are active to different degrees when people are in different psychological states. Mapping EEG activities in different locations shows what areas of the brain are involved in what kinds of mental activity
Early view of the function of sensation seeking
Regulates exposure to stimulus intensity "High sensation seekers open themselves to stimulation; low sensation seekers protect themselves from it. Both tendencies have advantages and disadvantages. People high in sensation seeking should function well in overstimulating conditions, such as combat, but they may display antisocial qualities in situations that are less demanding. People lower in sensation seeking are better adapted to most circumstances of life, but they may "shut down" psychologically when things get too intense
Oxytocin
Related to lower lifetime aggression Related to negative affectivity and social inhibition Not much evidence linking oxytocin to personality traits
Broader view of sensation seeking's function
Relates to the demands of social living Impulsive unsocialized sensation seeking (IUSS) = "a deficit in the capacity to inhibit behavior in service of social adaptation. IUSS relates inversely to sociability and positively to aggressiveness" Focuses on the immediate consequences of behavior, rather than longer-term consequences
Right-prefrontal cortex
Right-prefrontal areas are more active when people are feeling anxiety or aversion—for example, when viewing film clips that induce fear and disgust
Role of impulsivity
Second issue on which conceptualizations of extraversion have differed concerns impulsivity impulsivity with positive affect (the key to extraversion) belongs in extraversion but that impulsivity without positive affect doesn't Zelenski and Larsen found that measures of impulsivity loaded on a different factor than did extraversion (which loaded on the BAS factor). Also relevant to this issue is evidence from research with monkeys. One study (Fairbanks, 2001) found that social dominance, which many see as part of extraversion, relates to moderate impulsivity—not high or low. On the whole, evidence suggests that impulsivity does not belong in extraversion
Problems and prospects for the genetic and evolutionary perspective
Since many personality traits seem heritable and many of the traits relate conceptually to temperaments, perhaps we should view temperaments as the starting points from which the conceptually related traits emerge Maybe we should be asking whether temperaments are unitary, broad qualities that are just displayed in diverse ways or whether they instead are convenient aggregates of what are really separate traits A final question concerns the fact that the genetic approach to personality intrinsically takes no position on how personality should be conceptualized or what aspects of personality matter Some people view these overtones of evolutionary thinking as racist and sexist, and some have shown considerable hostility toward the theories themselves
Incentive approach system
Structures involved in approach have been given several names: activation system, behavioral engagement system, behavioral facilitation system, and behavioral approach system (BAS) "go" system; reward-seeking system This set of brain structures is presumed to be involved whenever a person is pursuing an incentive. It's likely that some more-specific parts of the brain are involved in the pursuit of food, others in the pursuit of sex, and others in the pursuit of shade on a hot summer day. But it's thought that those separate bits also link up to an overall BAS. Thus, the BAS is seen as a general mechanism to go after things you want The BAS is also held to be responsible for many kinds of positive emotions, such as hope, eagerness, and excitement, which can be seen as reflecting the anticipation of a reward people with reactive approach systems are highly sensitive to incentives, or to cues of good things about to happen. Those whose approach systems are less reactive don't respond as much (either behaviorally or emotionally) to such cues
Early exposure to hormones, even prenatal exposure, can influence later behavior
Study of children whose mothers had received synthetic hormones while being treated for complications in their pregnancies (these hormones act somewhat like testosterone)
Tend and befriend -- responding to stress
Taylor et al. think the existence of these responses reflects a difference in evolutionary pressures on males and females, due to differing investment in offspring. That is, as just noted, fighting and fleeing may make good sense for males, who aren't carrying offspring (or pregnant), but it makes less sense for females. Females thus may have evolved strategies that benefit both themselves and their offspring Tending refers to calming offspring. This protects them from harm. That is, if they don't cry, they (and you) fade into the background, where the threat is less. By extension, you do the same for close adults who are stressed. By soothing them, you put them into a situation of less threat. Befriending means affiliating and bonding with others. This reduces certain kinds of risk (because there's greater safety in numbers) and increases the chances of receiving tending from each other when needed This system involves a hormone called oxytocin. It acts to relax and sedate, to reduce fear, and enhance mother-infant bonding. Both males and females have this hormone, but females have more of it. Furthermore, androgens inhibit its release under stress, and estrogen increases its effects. Thus, men and women react somewhat differently to stress. Men tend to remove themselves from social interaction; women immerse themselves in nurturing those around them
Hormones, the body, and the brain
Testosterone differences in gestation are essential to changes in the nervous system that create normal male and female physical development. Many researchers believe that the hormones also change the brain in ways that result in behavioral differences basic template for a human body is female. Only if hormones cause specific changes to occur does a body emerge that looks male. If a genetic male isn't exposed to androgen ("male-making") hormones at critical points in development, the result will be an exterior that looks female. If a genetic female is exposed to testosterone at the same points, the result will be an exterior that looks male The hormones that guide the body in its sexual development also affect nerve cells. They organize the developing brains of males and females differently, in subtle ways. Animal research suggests there aren't just two patterns but a broad range of variation, with male and female patterns as the extremes. The genders tend to differ in linkages among synapses and in the size of some brain structures -- ex. the two sides of the cortex are more fully interconnected in women than men. Interestingly, there's evidence that the brains of gay men structurally
Decrease in testosterone
Testosterone falls after a failure or humiliation May cause a person to be less assertive and avoid new competition
Increase in testosterone
Testosterone rises after positive experiences Increase makes people more sexually active Increase can also make a person seek out new competition and chances to be dominant Increase makes people more responsive to possible rewards and less responsive to possible losses Makes them less empathetic Less able to detect anger on another person's face
Antisocial behavior
There is evidence that temperaments play a role in this sort of problem, particularly the approach temperament we should not frame questions in terms of whether genes influence this disorder but rather who is at greatest risk for the disorder when placed in circumstances that elicit problem behavior
Complications in behavioral genetics
There is often a correlation between a genetic influence and an environmental one; Makes it very hard to sort out causal responsibility ex. The environment had the actual effect on their IQ. But the possibility for it to happen stemmed from their genetic makeup. Thus, the two influences are correlated ex. Maybe those environments even induce people to develop more of what first led them to go there Size of genetic and environmental influences depends partly on how much variability there is in each of them
Threat sensitivity vs. Incentive sensitivity
Threat sensitivity and incentive sensitivity are thought to be relatively separate. People presumably differ from each other on both. As a result, all combinations of high and low approach and avoidance sensitivity probably exist
Link between the approach system and extraversion
Various extraversion packages (tendency to experience positive emotions) resemble BAS function fairly well Extraversion relates to the volume of brain areas associated with approach, such as the medial orbitofrontal cortex Extraverts are responsive to positive mood manipulations; those high in BAS sensitivity also have positive feelings to impending reward
Why do gene pools matter?
What ultimately matters is a gene pool, in a population. If one group in a population survives, prospers, and reproduces at a high rate, its genes move onward into subsequent generations more than other groups' genes
Young male syndrome
When males face hard competition for scarce resources (females), the result sometime is confrontation and potentially serious violence viewed as partly an effect of evolutionary pressures from long ago and partly a response to situations that elicit the pattern. That is, although the pattern of behavior may be coded in every man's genes, it's most likely to emerge when current situations predict reproductive failure In line with this analysis, there's clear evidence that homicide is primarily a male affair
Biological bases of anxiety and depression
With anxiety disorder, the avoidance system creates fear or anxiety in the presence of cues of impending punishment. A person with a very sensitive threat system will experience these emotions easily and frequently. This creates fertile ground for an anxiety disorder to develop. If these people are exposed to frequent punishment during childhood, they learn anxiety responses to many stimuli A related problem is depression. There's less consensus on the biological roots of depression than on those of anxiety. Some researchers see depression as a variant of anxiety, reflecting an oversensitive avoidance system. Others tie depression to a weak BAS
Evolution and problems in behavior
Your experiences of life stem partly from what biological evolution shaped humans to be during prehistory and partly from the cultural circumstances in which you live Barash (1986) pointed out that biological evolution prepared us to live in a world very different from the one we live in now. Cultural evolution has raced far ahead, and biological evolution can't keep up -- That is, problems emerge when behavioral tendencies that have been built in as part of human nature conflict with pressures that are built into contemporary culture
Neurotransmitter
a chemical involved in sending messages along nerve pathways
Effects of early exposure to hormones
a sex difference: Boys chose this response more than girls did effect of prenatal exposure to the hormone. Children who had been exposed chose physical aggression more than children who hadn't been exposed. This was true both for boys and for girls Shows how hormones can influence behavior early exposure can increase the potential for aggression, lead to preference for masculine toys, and enhance boldness
Testosterone, dominance, and evolutionary psychology
aggression can increase males' opportunities to mate. Aggressiveness helps males establish dominance and status There are also interesting individual differences in testosterone effects. For example, after being insulted, men from the American South have a greater increase in testosterone than men from the North. This has been interpreted as indicating a stronger culture of honor in the South, which increases the impact of an insult Nonetheless, testosterone does relate to aggression among women as well as men. That this can be a problem for women is suggested by findings that this assertive style interferes with forming alliances in female groups Success is now defined partly by socioeconomic status, rather than physical dominance. A man who's too preoccupied with displays and posturing may have trouble gaining the skills needed for economic and social power. Thus, a quality that was important in prehistory may actually interfere with success in today's world
Other methods to study inheritance
an adoption study, which looks at how adopted children resemble the biological parents and the adoptive parents. Resemblance to biological parents is genetically based, whereas resemblance to adoptive parents is environmentally based combines features of the twin study with features of the adoption study. It's sometimes possible to study MZ twins who were adopted and raised separately
Temperament
an inherited personality trait present in early childhood
Mary Rothbart's argument
argue for approach and avoidance temperaments, which reflect tendencies to approach rewards and avoid threats, respectively
Dopamine
argued that it is involved in the approach system higher dopamine reactivity has been related to higher positive emotionality, novelty seeking, and to several aspects of extraversion, flexible shifting among goals, distractibility One current view is that bursts of dopamine in response to reward increase the learning (and the execution) of approach responses, and that dips in dopamine after nonreward increase the learning (and the execution) of avoidance responses Some have concluded that dopamine is mainly about motivation, rather than learning—that is, that dopamine is involved in approach-related effort
Monozygotic twins/identical twins
because they came from what was a single cell, they are 100% alike genetically
Effect of serotonin
computed averages separately for positive and negative feelings and related them to the men's levels of serotonergic function. Higher serotonergic function related to less negative affect, consistent with the findings just reviewed. However, higher serotonergic function also related to lower levels of positive feelings (interested, active, attentive, and enthusiastic). Thus, serotonin may provide a constraining influence over the biological systems that manage affects of both sorts Consistent with the view that serotonergic pathways are involved in impulse control and that the resulting restraint (when it does occur) is effortful, rather than an involuntary reaction
Positron emission tomography (PET)
derives a picture of brain functioning from metabolic activity. The person receives a radioactive form of glucose (the brain's energy source). Then later, radioactivity is recorded in different brain areas. Presumably, more active areas use more glucose, resulting in higher radioactivity there. A computer color-codes the intensities, producing a brain map in which colors represent levels of brain activity
Testosterone's behavioral effects
dominance antisocial
Nonshared environmental effect
environment seems to affect personality mostly by making twins different ex. Having different friends may cause twins' personalities to diverge ex. Role of the child; different styles of interacting ex. How a child is treated differently than the other
Low serotonin
findings suggest that low serotonin function made people act more the way they tend to be anyway. That would fit with the idea that low serotonin means loosening restraint of one's basic tendencies Although there's a lot of evidence linking low serotonergic function to aggressiveness, most researchers seem to believe that the link is more directly to impulsiveness in reacting to emotion than to hostility per se
Genome
genetic blueprint of the body Increasingly possible to identify specific genes that influence differences among people - from vulnerability to disorders to normal personality qualities
Heritability
index of genetic influence on a trait; represents the amount of variability in the population that's accounted for by inheritance in the trait under consideration. The higher the heritability, the stronger the evidence that genes matter does not represent the amount of a behavioral characteristic that's inherited by any one person. Nor does it explain why genes matter
Transcranial magnetic stimulation (TMS)
involves focusing a magnetic field on a specific location in the brain. Because of the magnetic properties of active neurons (discussed earlier), applying this stimulation has the effect of either reducing activity in the area it's aimed at (if the pulses are low frequency) or increasing it (if the pulses are high frequency Used to increase activity in the left frontal brain areas (approach behavior) Used to reduce activity used in right frontal areas
problems and prospects for the biological process perspective
it's hard to tell what's going on in the nervous system. To really know what connects to what in the brain means tracing neural pathways, which can't be done in human subjects
Serotonin
long been believed by some to be involved in anxiety or threat sensitivity; this view has been strongly challenged
Genotype
means they have different alleles at some particular location
Mate retention
men report spending a lot of money and giving in to their mates' wishes. Women try to make themselves look extra attractive and let others know their mate is already taken Men use their tactics more if they think their wife is physically attractive. Men also work harder at keeping a wife who is young—independent of the man's age and the length of the relationship women work harder at keeping a husband with a high income. They also make more efforts if their husband is striving for high status
Third temperament
newer theorists also posit a third temperament that's generally termed effortful control. This temperament is about being focused and restrained. In part, it reflects attention management (persistence of attention during long tasks). It also reflects the ability to suppress approach when approach is situationally inappropriate. This temperament seems to imply a kind of planfulness versus impulsiveness
Biological bases of antisocial personality
often argued that people with this personality have an overactive BAS they pursue whatever incentive comes to mind. It's also sometimes argued that they have deficits in the threat system.Thus, they fail to learn from punishment or aren't motivated to avoid it Insufficient MAO (associated with this system) may also be a vulnerability, interacting with an adverse environment. In one study, boys with alleles causing low MAO engaged in more antisocial behavior—but only if they also were maltreated while growing up
Candidate gene strategy
particular gene locations were examined selectively, based on evidence linking those genes to particular biological processes, as well as theoretical reasoning linking those biological processes to personality Several genes have been identified that appear to have clear relevance to normal personality -- ex. gene called DRD4, which relates to receptors for dopamine in the brain. It has several alleles, one longer than the others. Two research teams found almost simultaneously that people with the long allele have high scores on personality scales that relate to novelty seeking; also been linked to risky decisions and difficulty delaying But most genetic influences on behavior will involve small contributions from many genes
Assortative mating
people choose mates on the basis of particular characteristics Often, features that influence mate selection are similarities to the self
Sociobiology
proposed as the study of the biological basis of social behavior Core assumption was that many -perhaps all—forms of social interaction are products of evolution Accounted for altruism
Magnetic resonance imaging (MRI)
relies on a very subtle property of nerve activity. Nerve cells create magnetic fields. With a good deal of computer assistance, the magnetic resonances of a person's brain can be translated into a visual image. Typically, the image is of slices across the brain, as seen from above. Different slices give different information, because they show different parts of the brain
Avoidance/withdrawal system
somewhat distinct system in the brain that reacts to punishments and threats, rather than incentives Activity in this system may cause people to inhibit movement (especially if they're currently approaching an incentive) or to pull back from what they just encountered. You might think of this system as a psychological brake pedal—a "stop" system or a "throw-it-into-reverse" system Responsive to cues of punishment and danger thought to be responsible for feelings, such as anxiety, fear, guilt, and revulsion Sensitivity relates to learning for negative outcomes, not positive ones
To what extent are these various affects distinct and separate
study found that not only were the five supertraits heritable, but so were most of the facet traits. Indeed, the genetic influences on facets were separate from the genetic influences on the overall traits. This suggests that many distinct qualities are genetically influenced, not just a few broad ones
How much behavior change is possible?
suggested that even true temperaments can be modified, within limits seems likely that some kinds of change are more difficult to create and sustain for some people than for others. For example, it will be harder for a therapy aimed at reducing emotional reactions to be effective for someone high in emotionality than for someone lower in that temperament There's a good deal of influence from experiences. Thus, the data that establish a genetic influence on personality also show that genetic determination is not total
Brain areas in extraverts
techniques have yielded evidence that extraverts have larger volumes of brain areas associated with approach, such as the medial orbitofrontal cortex
Cycle of testosterone and action
testosterone is also part of a dynamic system that changes over time and events. Levels of testosterone shift in response to social situations of several types. These shifts may, in turn, influence the person's later behavior
Molecular genetics
the attempt to relate differences in particular gene locations to other measurable differences among persons
Genome-wide association studies
the entire genome is examined for any and all differences that relate to an outcome of interest
Evolutionary psychology
the idea that human behavioral tendencies have a basis in evolution ex. Because cooperation promotes better group outcomes, some conclude that a tendency to cooperate is part of human nature ex. But there's also evidence that punishing people who don't cooperate leads to better group outcomes. Maybe punishing people for such actions (taking revenge) is also genetically built into human nature ex. even after people have transgressed and been punished, there may be important reasons to restore the damaged relationship. This suggests an evolutionary role for forgiveness
Mate selection
the strategy of women is to tend to hold back from mating until they identify the best available male. Best here is defined as quality of genetic contribution, parental care, and material support for the mate and offspring the strategy of males is to maximize sexual opportunities, copulating as often as possible. This also means seeking partners who are available and fertile
Behavioral Genetics
the study of genetic influences on behavioral qualities Twin Study
Inclusive fitness
there are ways to get your genes carried forward besides reproducing on your own. Your genes are helped into the next generation by anything that helps your part of the gene pool reproduce ex. If an extremely altruistic act (in which you die) saves a great many of your relatives, it helps aspects of your genetic makeup be passed on because your relatives resemble you genetically
Incentives
things they want
Avoidance of incest
too much similarity creates problems. If parents are very closely related to each other, it increases the chances that harmful recessive mutations will be expressed. The result can be poorer health and lower survival for the offspring
Pharmacotherapy
treatment that involves administering drugs Treat schizophrenia Treat bi-polar or manic-depressive disorder Treat anxiety
Quantitative genetics
twin research
Dizygotic twins/fraternal twins
two eggs released from the mother's ovary; on average they are 50% alike but can range from 0% to 100%
Concordance
used to describe similarity of diagnosis Appears that inheritance plays a role in schizophrenia; life circumstances also play a role in determining who shows schizophrenic symptoms openly
Alleles
when different patterns of DNA occur at a particular location Polymorphism = the existence of a difference at that location
