L6: Genetics, Intelligence, Language Flashcards
what is a gene
- Unit of heredity transferred from parent to offspring
- In humans, 50% of the genetic material is from the
father (sperm) and 50% is from the mother (egg) - Genes encode for proteins, which are an essential
structural component of every organism - Because genes determine the structure of the nervous
system, they also determine its functional output
what is the pathway from genes to behavior
DNA - RNA - protiens/peptides from amino acids - neuronal structure - brain structure - behaviour
all are effected from the environment
Variations in genes can lead to variations in
behavior.
how many genes are there and what are in these genes
~20 000 – 25 000 different genes
* Each of these genes may have multiple alternative
versions (alleles) with different functions
how can alleles be compared to computers
- Most computers have
the same basic parts
(video card, motherboard,
keypad…) - However, the type of part
each computer has is
different - Depending upon the part
the computer has, it
functions differently
what to genes determine
The genes we inherit from our parents play a powerful role in determining our physical traits, including eye colour, hair colour,
height, weight, body shape and more.
what are the genetic differences we have within our families
The more similar we are genetically, the more similar we tend to be behaviorally. most similar to our siblings and parents than others in our family
how can we correlate genetics with behavioural similarity in twins
monozygotic twins = 100% identical genetically
- in psychology it is tested that they have very similar personality traits and behaviour
dizygotic = 50% identical genetically
- their behaviour is variable but still pretty similar
what is variation and heritability?
- Within a population, traits may vary significantly
(phenotypic variation, VP) - This variability in traits may be due to changes in
genetic factors (VG) or changes in environmental
factors (VE)
VP = VG + VE
- Heritability (H^2) is the proportion of phenotypic
variation explained by genetic factors, such that:
H^2 = VG/ VP
what psychological traits are heritable?
- Many psychological traits – including personality (most heritable), intelligence (middle), ideology and even religiosity (end) – are heritable
- In some cases, the heritability increases with
age (e.g. for intelligence) - Environment usually plays a big role, as does randomness
- disorders are also very heritable, some more than others (bipolar, schizophrenia, alzheimer’s, more than, GAD, MDD)
what is the conclusion to nature vs nurture
This is not a real debate and never has been. Both
forces are significant and interact with each other.
Knowing these interactions can be useful!
why do traits become common?
With severe environmental pressures, certain traits
become advantageous (i.e. are selected for)
* In epidemics, disease resistance traits (humans)
* W/antibiotics, antibiotic resistance traits (bacteria)
People with these traits have more offspring (or
greater reproductive fitness)
* Alleles for traits that increase reproductive fitness become
more common in a population
* Alleles for traits that reduce fitness become less common
- Without environmental pressures, allele frequencies
likely won’t change much in a population
what is sexual selection
Selection for a trait that doesn’t directly increase
survival, but does increase reproductive fitness (via
increasing appeal to the opposite sex)
blue eyes, or a pecocks feathers
key principles of heritability
- All traits are heritable (often ~50%)*
- No trait is 100% heritable. The environment always
explains some behavioral variability (often ~50%)
key principle of variation
- A typical trait is associated with many genetic variants,
with each accounting for a very small percentage of
behavioral variability (< 1%) (one trait, many genes)
what is pleiotropy
Genes can serve many functions (one gene, many traits; termed pleiotropy)
key prinicples of genes
Genes affect the likelihood of encountering
environments and the response to environments
* Genes for creativity may attract us to artistic disciplines
* Genes for IQ permit entry into high-level universities
* Genes for stress resilience may lower depression risk in
response to stressful life events
Avoid value judgments as much as possible. Whether
a trait is ‘bad’ or ‘good’ can depend upon the context!
* Genes for low alcohol resistance reduce risk for addiction
There are no necessary policy implications
what is intelligence
‘the capacity to acquire and apply knowledge and skills’
- A conceptual variable
- Easy to define but challenging to study
Today, we will review several theories of intelligence
* G theory (also called General Intelligence Theory),
Sternberg’s Theory and Gardner’s Theory
what is g theory of intelligence?
- There are many different cognitive abilities (reading,
writing, mathematics…) - We can measure these abilities using tests
- In a population, the results of different cognitive tests
are highly correlated - If you do well on one cognitive test, you generally do well on other tests
- A common element (g) contributes to all cognitive abilities (an ‘engine’ driving all cognitive processes)
- if you have a strong g you will have a stronger result in all the cognitive tests (math, recall, verbal, perceptual, spatial, language…)
Does this mean that ALL our cognitive abilities are
ENTIRELY driven by a single attribute (g)?
NO.
- The correlation between g + cognitive abilities is not 1
- A proportion of variability in each ability is not explained by g
and must be explained by something else - In addition to g, which drives all abilities, each ability
may be driven by its own specific factor (s) - Ability performance = g (shared by all abilities) + s (unique to
the ability)
so for all tests the g is constant but the s factor is different.
how can you estimate g? how does it work?
- The most popular technique for estimating g is the intelligence quotient (IQ) score
- IQ is an operational definition of intelligence
- In an IQ test, we give an individual many cognitive
tasks and observe their performance - All this performance data is fed in to a single equation
which gives an IQ score - Several IQ tests; Weschler Adult Intelligence Scale
(WAIS) tests most popular (high construct validity)
how is wais testing structured?
Full-scale IQ –> verbal IQ and Performance IQ
Verbal IQ = verbal comprehension index, working memory index
performance IQ = perceptual organization index, processing speed index
what are some barriers in cognitive testing? and how can you reduce them?
- Language ability and culture are concerns
- IQ tests developed for one group (e.g. for Europeans)
may not apply well to another (e.g. African-Americans) - To reduce the influences of language and culture, it is
important to use culture-specific tests and nonverbal assays (such as Raven’s Matrices) - Famously, Weschler himself (a Romanian immigrant)
was mistakenly identified as impaired as a child
what is the mean and SD of the IQ test
- normal distribution, with random sampling
- M = 100, SD = 15; ~68% scores between 1 SD
- If you’re reading this, you’re likely in the 100-115 range
other perspectives on intelligence: crystalized vs fluid intelligence
types of intelligence:
fluid: abstract, connections
crystalized: trivia, facts
- crystalized goes up and fluid goes down through increasing age
other perspectives on intelligence: sternbergs theory of intelligence.
why is this model important
analytical intelligence: academic problem solving and computation
- measured by IQ tests
creative intelligence:
Imaginative and innovative solving
Practical intelligence:
street smarts and common sense
This model is important because it emphasizes the role of creativity.
