Lecture 6 - bahaviour genetics, intelligence and language

what is a gene

• unit of heredity transferred from parent to offspring

• genes encode for proteins

• genes determine structure and functional output of nervous system

From genes to behavioural traits

DNA

RNA

protiens (rna translated to protiens)

biological process in nervous system (protiens influence nervous system)

trait

genetic variation

• 20,000-25,000 different genes

• each have differnt alternative versions (alleles) w different functions

differences in alleles

different versions of the same gene

• can change how nervous system functions

• can lead to differences in protiens

• which lead to differnces in thought and behaviours and traits

monozygotic and dizygotic twins

monozygotic

• identical twins

• one zygote

dizygotic

• fraternal twins

• two zygote

Heritability

• the proportion of phenotypic variation explained by genetic factors

  • Vp (phenotypic variation) = Vg + Ve

  • H2 = Vg/Vp

• a mathematical estimate

• can be innaccurate (based on assumption)

• context specific (heritability score for one group may not apply to another)

• never 100%

heritable traits

• personality, intelligence, ideology, religiosity, disorders

Nature (genetics) vs Nurture (environment

• the debate of genetics vs environment is not real

• both are important

• traits and behaviours develop from both combined

reproductive fitness and why do trait become common

• traits that go on to the next generation

• genes become common

• traits that help individuals have more offspring become common

  • example: disease resistance traits help people live longer and produce more

  • example: attractive traits can lead to more mating opportunities

    • these traits are selected for and become more common in population

How do scientist measure heritability

• used twin studies (before 2000)

  • lot of assumption and problems

• used molecular heritability (looks at the genes) ( after 2000)

  • more accurate

• uses mathematical models (today)

Genes influencing the environment

• genes can shape the situation you end up in and how you respond to it

  • a gene related to creativity might lead you to seek out art-related activites

• weather a gene is helpful or harmful depends on the situation

what is intelligence

• the capacity to acquire and apply knowledge and skills

• conceptual variable

• challenge to study

the idea of g (general intelligence)

the idea that a single underlying ability influences performance across different intellectual tasks

• students tend to get simmilar grades across different subjects (A student will normally get As in all classes)

• also tru for cognitive tasks

• r value is strong

the positive manifold

• when your good at one thing, your most likely to be good at another

• when you measure performance on different tasks, the scores are positively correlated

• if someone does good on one task, they usually do well on the others

factor analysis

• finds methods in how tasks are related

• shows that different abilities are connected and can be grouped into broader categories called G factor

general intelligence theory (g)

• a mental ability that influences performance acorss many different cognitive tasks (memory, reasoning, problem solving, etc)

• not all cognitive abilities are driven by g

• correlation is not perfect

• each abilit has a general factor and a specific factor

• abillity = g + s (math ability = general intelligence + math-specific skill)

• g is important but doesnt garentee success

how do we measure intelligence

WAIS testing

• Measures Full-Scale IQ (FSIQ), which is broken down into Verbal IQ (VIQ) and Performance IQ (PIQ)

barriers in cognitive testing

• language ability and culture are concerns

  • to reduce influence, we can apply culture-fair tests and non-verbal assays (like Ravens Matrices)

Intelligence Quotient (IQ)

• measures cognitve ability compared to general population

• normal distribution

why do peopel care about IQ

• can predict success

  • in the termans study, kids w high IQ grew up to be successful in life

correlates of IQ

most likely to (positive correlation)

• live longer

• be taller and weigh more

Less likely to (negative correlation)

• commit crimes

• get divorced

• IQ is moderatly related to income

• weakly related to wealth

• other factors play a role (personality, etc)

IQ and leadership

• intelligence is related to better leadership

• very high IQ can hurt how poeple view your leadership ability

  • extremely smart leaders might eb harder to relate to

    • becomes a curvilinear relationship

heritability of IQ w age

• increases as we get older

why does heritability increase

• genetic mutation of environment

  • People with higher IQs tend to seek out or be drawn into environments that further improve IQ

• innovation

  • Some IQ-related genes only become active later in life, influencing intelligence at that stage

• Amplification

  • The influence of these IQ-related genes increases over time, making genetic effects on IQ stronger with age.

the flynn effect

• suggests that environemnt matters (plays a role in IQ)

• possible factors: better nutrition, more education, complex modern environments (technology)

• proves that environment can raise IQ

  • to a point (ceiling effect)

Ceiling effect (asymptote)

• after reaching a certain level of environemnt quality, extra improvements dont help much

  • commercial brain games dont work

  • parenting stratefies have weak influence

scarcity mentality

scarcity = not enough resources (like money, time, food) or worrying about not having enough

poverty can lead to impaired cognition leading to worse poverty

pollution on IQ

• lowers it, same w lead poisoning and same w COVID cause of social isolation

intelligence and info processing

• intelligent people think quickly

• reaction time is negatively correlated w IQ (IG goes up, reaction time goes down)

• reaction time is a predictor of dementia in elderly

• high IQ people show more efficient brain activity on moderate difficulty and less overall brian acitivy during difficult tasks

• people w higher IQ dont always learn quickly

cortical thickness

• correlated w IQ

• declines w age and contributes to age related cognitive decline

what form of cognition declines first

• speed then accuracy

• education helps w less cognitive decline

criticisms w intelligence

• IQ predicts performance best at lower IQs and once past a certain point, IQ is less critical for performance (so there is restr5icted range)

• jobs and schools are purposfully structured like the tests so of course the test are correlated w performance

fluid intelligence

• ability to think quickly, solve new problems and reason w/o prior knowledge

• peaks in early adulthood and declines w age

• measured by pattern recognition, memory, reasoning speed

crystallized intelligence

• knowledge and skills you have learned through experience and education (vocab, facts)

• keeps improving or staying stable w age as long as you keep learning

sternbergs theory of intelligence (3 parts)

analytical intelligence

• academic problem-solving, logic, computation

• what IQ tests usually measure

creative intelligence

• ability to be imaginative, generate new ideas, solve novel problems

practical intelligence

• “street smarts”

• knowing how to adapt, apply knowledge and use common sence IRL

criticisms of sternberg’s theory

• practical intelligence is not independent of g

• difficult to prove relationship between job performance and practical intelligence

• “creative intelligence” is controversial cause people view creativity and intelligence separately

gardeners eight intelligences

• howard gardner believed that intelligence isnt one thing like IQ. he beleived there are strong types:

  • naturalist

  • spatial

  • musical

  • bodily-kinetics

  • linguistic

  • intrapersonal

  • interpersonal

  • logical-mathematical

criticisms w garderns theory

• there are no tests meaning its unfalsifiable (we cant predict anyhting)

• no specific guidlins

• the possiblity that they overlap w g hasnt been assessed

emotional intelligence

• an ability to perceive, understand , facilitate and manage emotions

• many people beleive it contributes to success

• strongest early proposal from Goleman

• MSCEIT

• controversial concept (difficult to study and define)

• correlated moderatley w job performance

MSCEIT (Mayer-salovey-caruso emotional intellegence test)

4 branches

• perceiving emotion

• understanding emotion

• facilitating thought w emotion

• managing emotion

language

• arbitrary system of communication that combines symbols such as words or gestural signs to create meaning

• called the crown jewel of cognition

• used to record and transmit info

• affects our fitness and survival

• leanring language is diff than leanring skill

aspects of language

phonemes

• elementary school sounds

morphemes

• smallest units of menaing

syntax

• set of grammatical rules that control how words are put together

contextual

• important to understanding language

phonemes vary by language

• smallest units of sound in a language

• English has 44 phonemes

• each language is diff

emotion in language (Valence and activation)

words carry emotional meaning in two ways:

Valance

• how positve or negative a word feels (ex. love =positive, hate=negative)

Activation

• how much energy or intensity a word had (hate = high activation, cold = low activation)

sound symbolism

• people associate sound w shapes

• shows that sound has inherent symbolic meaning

syntax

• set of rules which we construct sentences (rules for how we arrange words)

• varries by language

• corrct syntax does not always result in comprehensible language

• grammatically

language difficulties

broca aphasia

• difficult in speech but understands

wernickes aphasia

• difficulty in both speech and comprehension

alexia/dyslexia

• difficulty reading

mixed aphasias are more common

language development in children

babbling (7 months)

common words (10-12 months)

abnormal in autism sectrum disorders

boys tend to speak later

bilingual people might speak later

sensitive periods for language

• easiest to learn from ages 3 to 7

• harder after 18 years old

• this is bc our brains are more flexible (plastic) at a young age

The Saphir-Whorf hypothesis

• postulates that structure of a language determines a native speakers perception and categorization of expierence

• ver difficult to test

  • cause language is combined w culture

  • our social attititeds influece our thoughts