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class 2 evolutionary theories.docx

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PSYC 3402
Shelley Brown

Week 2 A strong theory is: 1. Parsimonious (use of the simplest or most frugal route of explanation available) 2. Clearly identifies the CAUSAL MECHANISMS and corresponding MEDIATORS and MODERATORS underlying the phenomenon of interest 3. Is testable and hence falsifiable via hypotheses and predictions 4. Is based on empirical data and is modified in response to new data. 5. Possesses interdisciplinary compatibility 6. Respects gender ethnicity and culture Historical context • Franz Gall was founding father of phrenology theoretical perspective positing that there was a relationship between size and shape of a person’s head, and his/her personality, mental ability and behaviours. • Cesare Lombroso took gall’s work one step further and began comparing criminals (both male and female as well as prostitutes) to normal agents of the population o Criminals possess distinctive physical features such as sloping foreheads and twisted lips not observed in “normal” subjects o He referred to these features as atavisms and suggested that criminals were evolutionary throwbacks who had more in common with Neanderthals than modern day man The heart of evolutionary psychology… • the behaviors, thoughts, and emotions exhibited by our hunter/gather ancestors that increased the odds of survival for oneself and one’s offspring eventually become part of the human gene pool in the form of evolved psychological mechanisms – Genghis Khan – considered most brutal conqueror of all time, but most successful in terms of amount of land he accumulated in his empire. Ruthless and brutal, responsible for killing millions. – In the case of Khan—brutish and violent methods led to status/accumulated power/wealth— access to women – 8 percent of everyone in the world will have direct descendant to Genghis khan. – Violence, status and power can dramatically enhance ones reproductive fitness • Keeping multiple wives ensured his genes would carry on • It is a distal explanation that applies to the whole species. Explaining why/how we think the way we do due to an evolutionary advantage. More focused on physiology Examples of evolution – apes to humans? 1. Chance genetic mutation Evolution: Common Misconceptions/Criticisms 1. Determinism – it implies that we cant change. Its in our DNAso we cant change it. • But Just because its in your genes doesn’t mean its inevitable. • Arguably evolution is all about adapting to your ENVIRONMENT 2. Naturalistic fallacy – just because a theory is explaining something people think its right but its not morally right. Legitimizes aggression and violence among other myriad social injustices. (its SEXIST) - Agood scientist studies good or bad behaviour – doesn’t mean he/she endorses it 3. Natural selection is a conscious process – its not in our heads. - People do not act a certain way based on this theory . its all at a genetic level. Its all about the selfish gene. • Natural selection – Reproductive success • Are you successful in having babies and keeping them alive long enough so that they can have kids and pass on the genes. – Selection pressures • Things in the environment – Successful adaptations • Move from a genetic mutation that may nor may not be good for you to, it IS good for you because it gives you an advantage • Step 1: a potential adaptation appears in an organism’s genes by chance (i.e., a genetic mutation) • Step 2: the adaptation enhances the organism’s reproductive success (i.e., how good a person/animal is at having children and keeping them alive so the offspring can procreate and pass the mutation/successful adaptation into the next gene pool) • Step 3: selection pressures present during the hunter and gathering era decide the fate of whether or not a mutation becomes a successful adaptation • evolutionary psychologists posit that those traits or psychological mechanisms that ultimately enhanced reproductive success among our hunter/gather ancestors would be maintained in the gene pool. • traits that enhanced reproductive success— “the number of surviving descents who themselves go on to reproduce” (Campbell & Cross, 2012, p. 199), in the ancestral environment are known as successful adaptations. EVOLUTION and crime – researchers posit that recurring conflict over resources, mates, or offspring drove the selection pressures that shaped evolutionary adaptations, manifesting in a wide range of antisocial behaviours including violence (rape, homicide) and non-violent offences (theft)., Evolutionary Research Methods • Diverse – Historical, anthropological, cross-cultural – Psychological (questionnaires, experiments, observations) – The difference? The questions that are posed and how how results are interpreted ….Evolutionary forensic psychology • Hypothesizes that recurring ancestral selection pressures that caused conflicts (finding food/safe haven, avoiding predators, finding a mate) led to the development of evolved psychological mechanisms that manifest as crime/antisocial behaviour (today) only when certain environmental cues are present – Resource scarcity (food, shelter, money) – Mate scarcity – Threats to status/reputation • Says that “the [selection pressures] that may have caused conflicts during ancestral times, such as resource scarcity or difficulty finding a mate, determined what genes [psychological mechanisms] were passed on based on who was successful [having kids..] at overcoming these conflicts. This is why (arguably) strong men with the ability to fight off competition & reproduce frequently were able to pass on their genes and why females would choose these men (because they are a more reliable choice for passing on genes and ensuring offspring will survive). • “It theorizes that in an ancestral context, aggressiveness was an evolutionarily advantageous trait [successful adaptation] for males. These traits would help people to survive and protect their offspring long enough so that they could reproduce. Some traits passed down could have been adaptive in an ancestral context for hunters/gatherers but antisocial and criminal in today’s context” • Survival of the fittest = maximizing reproductive success • Jeff’s motivations: had to defend his perception that his status as a strong, formidable opponent/rival was being challenged Evolutionary forensic psychology Hypothesizes that recurring ancestral selection pressures that caused conflicts (finding food/safe haven, avoiding predators, finding a mate) led to the development of evolved psychological mechanisms that manifest as crime/antisocial behaviour (today) only when certain environmental cues are present • Resource scarcity (food, shelter, money), mate scarcity, threats to status/reputation Life history theory • Our ancestors had three jobs – Hunt/gather-ensure one’s own survival – Find& attract a mate (mating effort) – Nourish one’s offspring (parental investment) – Mating effort includes various forms of risky behaviour including fighting, willingness to fight, associated with traits such as dominance, physical prowess, strength • But there were 3 primary trade offs (costs & benefits) – Focus on own survival vs. finding a mate/reproducing – Quantity vs. quality of offspring – Parental investment vs. mating effort • Life history theory posits that natural selection has created psychological mechanisms that weigh the costs and benefits associated with resource allocation strategies AND • …that these cost/benefit mechanisms are dynamic—respond to changing environmental cues and factors such as age, gender, “future bleakness factor” & number of children you already have • The theory can still have relevance today because these environmental cues still exist today. – Today’s cues are • Remember: these evolved cost/benefit psychological mechanisms maximized reproductive fitness in the past but are activated today by the environment Using life history theory to explain gender differences in crime • Fact #1: males commit more crime, particularly more violent crime than females • How to explain this? Socialization theory Women are more socialized to be more nice and not to fight back. Evolution theory  says that its because its adaptive for men to engage in high mating effort than it was for females. So this is why they commit crime more. As a woman if you confront someone, it doesn’t make sense to attack someone because if you die, your kids die. According to life history theory, why might this be the case? – HINT: the costs and benefits associated with parental investment and mating effort were different in an ancestral environment for females vs. males..... What do sneaker salmons and psychopaths have in common? - Swim out to the ocean and come back. But some don’t even go out to sea and stay back. Once the ones who went out to the ocean come back to try to fertilize eggs, at the last second the sneaker ones sneak in and fertilize them too/steal them Psychopathy: Evolutionary adaptation or pathology? • An aside—what is psychopathy? Not criminally insane/mentally ill. They are fully sane except they are manipulative, superficial, no empathy, no guilt, promiscuity, etc. • Assumption—psychopaths do bad things, cause grievous harm to others, thus how can it possibly be adaptive? It is good for the gene • What is the answer? • They are stronger than normal people in the fact that they lack emotions, this is good for pushing society forward. Small group of population because it worked, using deviant behaviour. If everybody had this characteristic it would result in chaos, but since only a certain percent of people are then it is a successfully adaptive trait • Evolution says it is an adaptation as opposed to a pathology Criticisms • Explanations focus a lot on aggression and violence vs. other types of crime • Hard to apply to certain types of crime (child molestation) • Hard to disprove – If it is not an adaptation, then it must be a by-product of another adaptation, or a malfunctioning adaptation/pathology • Lots of theorizing (lots of talk); not a lot of empirical testing (not a lot of action) Biological explanations of crime • Genetics - – Twin/adoption studies • Twin studies – is the correlation due to parents passing on genes to child or if is it due to parents passing on criminal attitudes and criminal life skills through years of living together – Molecular genetics • Neurochemistry – Hormones – Neurotransmitters • Psychophysiology (heart rate) • Brain (structure & function) • Other—pregnancy, birth complications, toxins, diet Twin studies • Lange (1929) – first empirical quest for a ‘crime gene’ • Compared prison records of 13 pairs of monozygotic (MZ) (identical) twins with 13 pairs of dizygotic (DZ) twins (fraternal) • Incarceration concordance rates were 77% for MZ twins and only 12% for the DZ twins • Why is this considered evidence of a genetic cause to crime? Since they share 100 percent of their DNA it is clear that they share some sort of gene that makes them more predisposed to crime than dizygotic twins. If there is evidence of genetic contribution – higher concordance of crime between identical twins rather than fraternal. Limitations of twin studies • Lang’s study—numerous problems • Twin studies in general – MZ twins treated more alike by parents than DZ twins – MZ usually share one placenta and DZ twin usually have two – Enter—adoption studies Adoption Studies • 2 types – parent-offspring and sibling-offspring • Parent-offspring  Concordance rates or correlations between adoptive parents and adoptees antisocial behavior are compared to concordance rates between biological parents and adoptees.  If the biological parent/biological child crime concordance rate is greater than the adoptive parent/adopted child crime concordance rate you have evidence of heritability • Sibling offspring  Concordance rates between adoptive siblings are compared with concordance rates of biological siblings. Limitations of Adoption Studies • Generalizability problems given that adoptees have higher rates of antisocial behaviour relative to the rest of the population • The environments of adopted offspring tend to be more advantageous relative to the general population, thus reducing shared environmental effects due to restricted range. The research says…. • There have been over 100 twin & adoption studies examining the gene/crime connection – 55,525 pairs of participants! – Meta-analyzed! – The results? – ‘crime’ can be accounted for by • heritability (.41) • shared environment (.16) • non-shared environment (.43) – different environments - research increasingly shows that the gene-crime link is most likely not a direct conduit but rather a function of the mediational effects of inherited characteristic that PREDISPOSE an individual to antisocial behaviour. Pathways are not always direct and unidimensional - is there an interactive effect between genes and environment? E.g. is there a “gene” by “environment” effect? • Experience of maltreatment increased probability of receiving a conduct disorder diagnosis by 1.6 percent if they had lowest genetic risk and their twin had no conduct disorder • Experience of maltreatment increased probability of receiving a conduct disorder diagnosis by 23.5 percent if they had highest genetic risk, and their twin was diagnosed with a conduct disorder • molecular genetics - The main function of a gene is to produce proteins called amino acids (basic building blocks of life) - Proteins are ultimately responsible for the phenotypic
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