PSYC102 Darko Odic Term 2 2026

Intuition

you just know, feel it inside

pure observation

you have experienced it as so

authority

somebody tells u

science

a community of people following agreed-upon rules and processes for observing, predicting and explaining some part of our world

theories

possible explanations for why or how something works

hypotheses

predictions about what should happen in a specific situation

studies/experiments

observational tests of a hypothesis by creating or finding situations in which the hypothesis should hold true

universality

when formulating a hypothesis or theory, the number of people we believe it applies to

Scientifc skepticism

do not get attached to any theory/hypothesis

Peer review

send your conclusions for review from other scientists

Replication

multiple studies done the same way should generate similar data; no single study “proves” anything, we always accumulate many

Falsifiable Hypotheses

make inflexible predictions that can be shown to be false with observation.

Openess

all data should be publicly avaliable (deal with unreliability of observation)

Double-Blind experiments

whenever possible, neither the participant nor the person collecting the data should be aware of what the hypothesis is (deal with unreliability of observation)

operational definition

description of a psychological property in measurable, observable terms

instrument

anything that measures the operational definition

construct validity

it measures what it claims to measure.

reliability

it gives similar measurements each time it is used

power/sensitivity

it can detect small differences in the measure

definition + instrument =?

data, a collection of measurements.

study design/methods

different types of studies that are typically used in psychology to observe and interpret data

correlational studies

estimate the numerical prediction between 2 measured variables

positive correlation

down to up (ex. more sleep associated with more stress)

no correlation

random spread (ex. more sleep has no association with stress)

negative correlation

up to down (ex. more sleep associating with more stress)

when one variable causes another…

they are usually correlated, but just because two variables are correlated does not mean that one is causing the other

directionality problem

for any correlation, A might have caused B, or B might have caused A

Third variable problem

for any correlation, a third, unmeasured variable C (“confound”) may be the true cause of both the measured ones

Coincidence

sometimes things in the world move up and down together through luck and random circumstances

Spurious correlations

strongly correlated variables that we know are not causally related, and correlate because of confounds and coincidence (ex. drinking milk will help win a nobel prize)

experiments

one variable is manipulated by an experimenter to see its causal effect on another (one group stays awake and we measure stress (experimental group), the other sleeps normally then we measure stress (control group))

Independent variable

the variable manipulated and predicted to have a causal effect.

Dependent variable (DV)

the variable measured, and predicted by to caused by the IV.

Random Selection/Sampling

participants should be chosen from the study randomly from the whole general population.

Random Assignment

participants are put into the IV groups randomly.

Solution to directionality

you control the direction by choosing which variable you manipulate and which you measure.

Solution to third-variable(s)

two groups will be theoretically identical in every third variable, so only difference will be from the manipulation you made.

Solution to coincidence

studies are replicated by other researchers multiple times to make sure the result wasn’t by chance.

intelligence

general ability to solve novel problems and learn from experience; about aptitude and not achievement

psychological factor

an element of psychology that predicts performance in a specialized domain, but not others

general intelligence factor (g)

the hypothesized single factor of intelligence that explains aptitude in all domains of knowledge

specific factor (s)

hypothesized individual factors of intelligence that explain aptitude in specialized domains of knowledge on top of g

Independent factor theories

intelligence is many non-overlapping abilities , each unrelated to the others

hybrid theory of intelligence

is a group of interrated factor, with g at the top “fueling” them all, various middle-level abilities after, and specific tasks underneath that

fluid intelligence (gf)

learning new information and solving novel problems

crystalized intelligence (gc)

apply knowledge learned from experience

Wechsler Adult Intelligence Scale (WAIS-V)

the most popular test used today, based on a hybrid model of intelligence

Full Scale IQ (FSIQ)

the total performance on the WAIS-V, and the best correlate to the concept of g

fluid reasoning

how well you solve novel abstract problems (Gf)

Processing speed

how quickly you reason and perform directed actions (Gf)

Visual-spatial

how well you solve visual pattern puzzles (Gf)

verbal comprehension

how well you understand language (gc)

working memory

how well you remember information over short time spans

Raven’s Progressive Matrices

a non-verbal intelligence test based on solving rules that create patterns in pictures ; a good measure of Gf

Intelligence’s controversies and limitations

Many psychologists use iq tests to filter and exclude people, raising ethical concerns, very little theoretical work is done across cultures…

Issues with IQ: education

content of intelligence tests overlaps with school content

Issues with IQ: test taking ability

are we measuring intelligence or test practice?

Issues with IQ: stereotypes

how well somebody does on a test depends on whether they think they should be doing well or not

Issues with IQ: cultural bias

different cultures have different definitions of intelligence

Individual differences

differences in psychological traits across people

Genetic variability

people differ in genes

environmental variability

people have different lives, have different conditions in the womb, grow up with different family styles, go to different schools, etc

their interactions

genetic effects change environments; environments change genetic expression

Genetic determinism

the false belief that if a person carries some set of genes, their expressed phenotype is fixed and immutable

Common mistakes when thinking about genes

Genes increase the probability of phenotypes, they do not determine them, no single gene predicts a single trait, genetics predict at the level of population, not the indiviudal

genetic predicton

1. the genetic range of possible phenotypes that could be expressed

2. how strong the influence of the environment has to be to change that range

factors to consider for intelligence

genes, early environment, later environment, confounds (maybe IQ tests are not measuring intelligence)

Quasi-experiments

study design where the independent variable occurs naturally, but has no random assignment or selection

Fraternal (dizgotic) twins

twins sharing 50% of their genes

Identical (monozygotic) twins

twins sharing 100% of their genes

Logic

if identical twins have stronger correlation than fraternal twins, then genes likely have an effect; if identical twins separated at birth have same correlation as identical twins raised together, then the effect of environment is likely small. Intelligence is most similar to height!

Other predictions for IQ: Education

the years and quality of one’s education is the strongest predictor; education is for IQ what nutrition is for height

Other predictions for IQ: Home environment

household income, home literacy, more predictable schedules, better access to health and nutrition

Other predictions for IQ: Birth Weight

small but positive correlation with higher birth weight

Other predictions for IQ: Birth order

first-born children have very slightly higher IQ than siblings

Flynn effect

average intelligence increases with each successive generation: improved environments, education, test taking abilities

Race in intelligence

asian-americans typically outperform white americans, who outperform hispanic americans, who outperform african americans, average IQ scores for the global south are lower than global north; differences range between 2 IQ points to 15

Race in intelligence, factors that can influence

sociocultural differences in environments (access to nutrition, education); gender gaps closing; gender differences within groups being much bigger than differences between groups

IQ: genetic

genes regulating neuron density or brain connectivity

will you have a significantly higher chance of high IQ if your parents have high IQ too?

yes

IQ: environmental

parents who like intellectual activities often share them with their children.

IQ: Socioeconomic

parents from affluent backgrounds and excellent education tend to retain that wealth and use it for their children, too.

IQ: Cultural Test Biases

a shared cultural background makes certain ideas easier to understand when explained or tested in a particular way.

IQ: Test Ability Confound

parents teach children how to do well on tests.

scientific objectivity

scientific theories should be accepted on the basis of scientific merit; personal opinions and cultural values shouldn’t influence this.

pherenology

the (today discredited) attempt to assess each person’s intelligence by measuring differences in “specialized” brain size through bumps on the skull.

why was pherenology not objective?

began with biased view, made sweeping conclusions from small differences, used biased samples, failed to replicate over time, relied on wrong theory of how the brain works

eugenics

the (today discredited) attempt to improve the genetic quality of humans in a population, most often through controlling who can have children.

why is eugenics rejected?

argues some humans lives are more valuable than others, only high value people should reproduce, reducing genetic diversity usually reduces long-term survivalibility of a species

the bell curve (1994 book)

advocates for changes in public policy to protect high IQ individuals and reduce reproduction for low IQ individuals

claims of the bell curve

1. intelligence is stable, genetically determined and reliably measured

2. intelligence tests are valid and unbiased

3. intelligence is the best predictor of life outcomes, job and school success etc

4. welfare allows low IQ individuals to have more children, decreasing overall fitness of our society

what does it mean to have low IQ?

IQ scores are relative to the population, not absolute, if everyone in our society became exceptionally smart, extremely small differences would still lead to somebody having an IQ of 80

how does twin studies show “genetic determinism” of IQ?

identical twins are more likely to:

• Have the same health conditions (e.g., ADHD, chronic pain).

• Have the same perceived level of attractiveness.

• Identify as the same gender.

• Have same physical characteristics that might influence hobbies and careers.

imagine that some set of genes strongly predicts IQ; would that

discovery support genetic determinism?

We have a strange society that filters people on an observable trait. Ex. Imagine a society in which only brown-eyed individuals are allowed to go to school. How much of IQ performance would be predicted by genes? Answer: ~99.9%.

should we, as a society, value IQ above other traits?

No. IQ correlates with some metrics of success Ex. school grades, performance on some types of jobs, lifetime income, longer lifespan. But none of these are causal, and might both be driven by, e.g., socioeconomic status or years of education.

State Differences

temporary differences in people’s psychology

Trait Differences

enduring differences in people’s psychology

personality

an enduring style of behaving, thinking and feeling

trait approach

personality is a set of universal gene+environment interactions

social-cognitive approach

personality is a product of learned reward and punishment from social situations