PSYCH 109 - Research Methods, Evolutionary Psychology, Cognitive Development

Merton's norms for science

communality, universalism, organised scepticism

dependent variable (DV)

measure of the behaviour we are interested in, on y-axis

independent variable (IV)

variable manipulated by experimenter to see if it affects DV, on x-axis

reliability

whether we get the same results if we measure the same variable again under the same conditions

validity

whether our variable really measures what we meant it to

population

all the events, scores etc. we are interested in

sample

representative subgroup drawn from population, preferably randomly. used to draw conclusions about whole population

sampling error

random samples drawn from the same population will give different results. chance variation. unavoidable, but minimised by using large samples

sampling bias

when a sample does not truly represent its parent population, usually because it was not drawn randomly. e.g., a minority ethnic group may be underrepresented. avoidable by random sampling

observational designs

look for correlation between two DVs. note that correlation doesn't always imply causation, so less powerful than experimental designs, but sometimes the only choice for ethical or practical reasons

experimental designs

manipulate IV and observe effect on DV. can imply causation, if effect is replicable. more powerful, but not always possible

confounding variable

a variable other than our IV which might have been responsible for any change inthe DV that we observed. an alternative explanation for our results. invalidates our experiment

controlling for potential confounding variables

hold them constant (esp. with external confounds, such as time of day, or stimulus lists in a memory task). randomise them (esp. with subject confounds, such as individual differences in ability on a task)

within-subject design

each subject is exposed to all levels of IV (all conditions). comparison is between each subject's performance in several conditions. internal (subject) confounds controlled, but could be external (environmental) confounds

between-subjects design

each subject only encounters one level of IV (one condition). comparison is between average performance of groups of different subjects in each condition. external variables can be controlled, but could be subject confounds

matched-pairs design

each subject is only in one experimental condition, but his/her behaviour is compared with a matched partner (according to subject confounds that might be important, like pre-existing ability at the task) in the other experimental condition. controls both external and internal confounds. good idea but not widely used

experimental group

group that receives the intervention (e.g., a new drug)

control group

group that doesn't receive the intervention, but is otherwise treated identically to experimental group. assess effect of intervention by comparing improvement of this group with experimental group

placebo

a sham drug (e.g., a sugar pill which looks like the real pill). given to control group in drug evaluations

single-blind design

subjects don't know whether they are in experimental or control group

double-blind design

subjects don't know whether they are in experimental or control group. experimenter who regularly interacts with subjects doesn't know which group they are in either

Stroop Effect

saying colours written in different colours. reading has become so automatic that it's hard to inhibit it. so when the colour of the print conflicts with the colour named, reaction time is slower

significance level

how likely it is that we might have got the same result just by chance. the criterion probability that we normally use is 0.05, or 5%, or 1/20. if the probability of our data occurring just by chance is less than 1 in 20, we'll believe that it's a real effect

H0 (null hypothesis)

there is no real effect, results obtained just by chance or sampling error

H1 (experimental/alternative hypothesis)

there is a real effect, results not obtained just by chance or sampling error

two-tailed hypothesis

does not specify the direction of the effect. e.g. "there is a difference between Groups A and B"

one-tailed hypothesis

specifies the predicted direction of the effect. e.g. "Group A will be higher/lower than Group B". must have a good reason for predicting the direction

Type I error

rejecting the null hypothesis when it is true. e.g. "Alcohol impairs memory ability" when there was no real effect of alcohol on memory

Type II error

accepting the null hypothesis when it is false. e.g. "Alcohol does not impair memory ability" when it actually does

how to measure location or average

by calculating the mean

how to measure variability or spread

by calculating standard deviation

degrees of freedom (df)

the number of scores that are free to vary while still producing the same two means

homology

shared inherited structures e.g. the vertebrate limb, frontal lobe

convergent evolution

the independent evolution of same structure where natural selection has favoured the same outcome from different ancestors. natural selection selects from same function

natural selection

three necessary conditions:

1. variation - different individuals in a population have different characteristics ie morphologies, physiologies, and behaviours
2. heritability - there is correlation between parents and offspring in the contribution of each to future generations
3. differential fitness - if resources are limiting, different phenotypes will have different rates of survival and reproduction because of differences in their design
over many generations, natural selection can generate adaptions

tool manufacture in animals

chimp used stick to fish for food, primate using rock to crack open nuts, New Caledonian crow observed using hooked twigs and leaf tools to retrieve grubs from logs, crow trained to pull string or use rocks for rewards

language in animals

Nim the chimp learned sign language and basic sentences, Kanzi the chimp learned vast vocabulary and basic sentences

domain specific intelligence

specific to a particular domain e.g. perhaps there are specific modules for language, vision, social cognition

domain general intelligence

integrates information across different domains

Vygotsky on language

language plays a major role in shaping thought: as we develop we internalise our speech which then allows us to develop complex thought

Piaget on language

language provides labels for experiences but is not central to the development of thought

probabilistic reasoning in animals

kea swap coloured tokens for food

genotype

what is inherited: the set of DNA molecules contained in nucleus, a genotype particular to a trait

phenotype

what develops: an organism's physiology, anatomy, behaviour

zooming in on DNA

body > cell > nucleus > chromosomes > DNA > DNA sequence

chromosome

thread-like structures contained in the cell nucleus. each chromosome is a DNA molecule. chromosomes occur in pairs. human somatic cells usually contain 23 pairs

gene

a stretch of DNA that produces a specific protein

locus

position of a gene on a chromosome

allele

alternative forms of a gene at the same locus

homozygous

when an organism possesses 2 identical alleles for a particular trait

heterozygous

when an organism possesses 2 different alleles for a particular trait

dominant

an allele that manifests its effects in both heterozygotes and homozygotes e.g. brown eyes

recessive

an allele that manifests its effects only in homozygotes e.g. blue eyes

polygenic inheritance

a trait whose phenotypic expression is influenced by many genes e.g. most psychological traits

violent "warrior gene"

Monoamine oxidase A (MAOA) - affects neurotransmitters in brain. claim that people who have particular MAOA allele are more likely to be violent. but if you look at the no maltreatment and low MAOA group, they actually have lowest antisocial behaviour - so warrior gene is contested. the effect of the gene is depended on the environment

heritability

the proportion of variation in a population that is attributable to genetic differences

heritability estimates

DO NOT apply to individuals (it's a population statistic).

DO depend on the range of environments and genotypes ie they are specific to the populations sampled.

DO NOT indicate the degree to which a trait can be modified.

DO assume additivity - that the genotype and environment "add up" the same way in all situations

heritability of IQ

how to separate the effects of shared genes from shared environments:

1. adoption studies
2. identical (monozygotic) vs non-identical (dizigotic) twins
3. separated identical twins

COMT - IQ gene

students with high IQ variant actually did worse on important test. so gene might not be for high IQ, it might be for stress and high conscientiousness about tests

Jim Flynn and the 'Flynn Effect'

IQ scores going up in populations everywhere

Herrnstein & Murray's argument

1. there are differences between ethnic groups and classes in IQ

2. IQ tests measure intellectual ability
3. IQ highly heritable
4. highly heritable traits cannot be changed
therefore:
· ethnic and class differences are genetic
· ethnic and class differences cannot (and should not) be changed

the Müller-Lyer illusion

both lines are actually identical. something about our visual system makes the bottom looks longer. even basic cognition varies across cultures

WEIRD psychology

Western, Educated, Industrialised, Rich, Democratic. make up most psychology subjects

pitfalls of WEIRD psychology

psychologists often implicitly ignore cultural variation, or assume that the population sampled is representative of all humanity

transmitted culture

cultural differences that arise due to information transmitted via social learning. not coded in genes, we get it from those around us

culture is adaptive

transmitted information isn't added bonus material, it is actually key to survival

human adaptations to social learning - overimitation

copying a behaviour, even when that behaviour appears irrelevant. if you're a child living in cultural world of knowledge, it is advantageous to copy what adults are doing even if you don't understand it. risk of not copying adults can risk survival

strategies for identifying the most reliable social information

conformist bias: copy the majority

prestige bias: copy the successful

descent with modification

language family tree tracks expansion pulses and pauses in Pacific settlement

Darwinising culture

cultural variation, cultural inheritance, cultural fitness

memes

cultural replicators

the selfish meme

compete for limited space in our brains. cultural selection for best replicators. memes can enhance or reduce our chances of survival. cultural fitness /= genetic fitness

aspects of mind

perception, action, cognition, emotion

psychology levels of analysis

genetic > physiological > neural > behavioural > social > cultural

developmental psychology

how does the mind change over the lifespan? focus on change and constancy

ontogenetic development

origination and development of an organism

evolutionary psychology

how was the mind shaped over evolution?

phylogenetic development

evolutionary history of groups of organisms (e.g. populations or species)

comparative psychology

how do different kinds of minds function? what are the similarities and differences among human and non-human minds?

basic research

research to expand our understanding

applied research

research to address practical issues

developmental approach: analysis

breaking a system down into components e.g. perception, action, cognition, emotion

developmental approach: synthesis

how those components come together

the developmental approach encourages…

a holistic, integrative view of the mind

quantitative change

numerically different (e.g. tadpole growing)

qualitative change

new structure, ability, or process (e.g. transition into frog)

nature vs nurture

are we the product of our genes or our experiences? its a false dichotomy, there’s always an interplay

epigenetics

gene expression can be modulated by experience

domain specific systems

are our minds supported by many specialised systems that evolved for specific domains? e.g. toolbox with specialised tools, phone with pre-installed applications

domain general systems

do we have a few general systems that can be used across many different domains? e.g. 3D printer that can make tools, learning algorithms that work for lots of domains

mechanistic view of the mind

mind is like a machine, with specific parts that perform specific functions

complexity view of the mind

mind is like an ecosystem, with lots of components that contribute to the broader system in many ways, and changes influencing different levels of the system

Piagetian Theory basic question

how do we get from just having reflexes as infants to having reason as adults?

genetic epistemology

the study of the origins of knowledge

Piagetian Theory: constructivist

child is not a blank slate but does not come "preloaded" with innate knowledge either, child actively "constructs" increasingly complex knowledge and abilities out of simpler components (e.g. reflexes)

Piagetian Theory: domain general mechanisms

development involves learning mechanisms that apply across domains, not many specialised systems for specific domains

Piagetian Theory: stage-based

children travel through a series of stages as they develop new knowledge and abilities. each stage forms the foundation for the next stage. development is about "levelling up". involves qualitative changes (e.g. the emergence of new abilities)

schemas

child's knowledge and ways of interacting with the world e.g. mouthing, shaking, looking, throwing

adaptation

linking the child's schemas and experiences in the world

assimilation

interpreting new experiences in terms of existing schemas