Task 9

Question 1

What is IQ?

Answer 1

Intelligence, also referred to as the g factor (general intelligence component/general cognitive ability), refers to reasoning, planning, problem-solving, abstract thinking, comprehension of complex ideas, quick learning, and experiential learning abilities. Cognitive domains: verbal & spatial abilities

Question 2

What are the subcomponents of IQ?

Answer 2

Verbal IQ (Verbal comprehension index & working memory index)

Performance IQ (Perceptual organization index & processing speed index)

Question 3

What are the two subcomponents of Verbal IQ?

Answer 3

Verbal comprehension index
Working memory index

Question 4

What are the subcomponents of Performance IQ?

Answer 4

Perceptual organization index
Processing Speed index

Question 5

What are the 4 tasks included in the verbal comprehension index?

Answer 5

Vocabulary
similarities
information
comprehension

Question 6

What are the 3 tasks included in the working memory index?

Answer 6

Arithmetic
Digit span
Letter-number sequencing

Question 7

What are the 3 tasks for perceptual organization index?

Answer 7

ppicture completion
block design
matrix reasoning

Question 8

What are the 2 tasks used for processing speed?

Answer 8

Digit symbol coding
symbol search

Question 9

How stable is intelligence?

Answer 9

• One of the most stable behaviour traits – correlation of 0.63 in a study of people tested at age 11 and then 79.
• E.g. a genetic correlation of 0.62 from age 11-69 was yieled using GCTA in a longitudinal study of intelligence.
• It is the best predictor of education and occupation outcomes.

Question 10

What are the three laws of genetics?

Answer 10

1. All traits show significant genetic influence
2. No traits are 100% heritable
3. Heritability is caused by many genes of small effect

Question 11

What are the 5 points concerning gene-environment influences on intelligence?

Answer 11

1. Heritability of intelligence increases dramatically from infancy through adulthood despite genetic stability
2. Intelligence indexes general genetic effects across diverse cognitive and learning abilities
3. Assortative mating is greater for intelligence than for any other trait
4. Thinking positively: the genetics of high intelligence
5. intelligence brings (some) genetics to ‘social’ epidemiology

Question 12

Explain why intelligence become more heritable with the increase of age, especially into adulthood

Answer 12

Genetic amplification:
In childhood, the child’s environment is chosen for them; these environment do not necessarily complement their genetic propensities. As they get older and have more freedom on their environment, the environment that they choose to create complement their genetic propensities.

Generalist genes hypothesis
* Differences in intelligence are caused by genes that affect other cognitive abilities (e.g. spatial ability, vocabulary, processing speed, EF and memory). There are different genes but they also affect other cognitive abilities.?

Question 13

Explain how assortive mating contribute to intelligence.

Answer 13

Assortative mating is greater for intelligence than for other traits. Largest for verbal intelligence.
* This is because people generally choose partners (assortment) that are of similar intelligence as them
* children with highly intelligent mothers are also likely to have highly intelligent fathers, and the offspring themselves are likely to be more intelligent than average. The same thing happens for less intelligent parents.
* In this way, assortative mating increases additive genetic variance in that the offspring differ more from the average than they would if mating were random

Question 14

Explain the genetics of high intelligence

Answer 14

• Intelligence show a normal distribution: at the positive end is high performance (gifted), and at the other problematic end is intellectual disability.
• the top 15% = has the same genetic heritability as the normal population
• top 4% = mixture of additive and non-additive genes (epistatic) interactions as emergenic
• the lower 4% on the other hand is caused by genetic mutations (non-inherited de novo mutations) as well as prenatal and postnatal trauma.

Question 15

Explain how intelligence bring some genetics to social epidemiology

Answer 15

• Intelligence is associated with health and illness outcomes (e.g. mortality)
• Intelligence is also associated with education and social class (e.g. social mobility)
• Some evidence show that educational attainment and social class are somewhat heritable, and they overlap with the genetic causes of intelligence differences.

that is, if a person is low on intelligence, and is also consequently low in social class, then there may be a poorer quality of life and increased mortality rate.

Question 16

Explain teh polygenic scores

Answer 16

• The heritability of intelligence is caused by thousands of DNA variants
• But additive effects of SNPs also account for hald of the heritability of intelligence.

Question 17

How can intelligence be measured?

Answer 17

Wechsler Adult Intelligence Scale (WAIS)
* Three IQ scores: verbal (6 subtest), performance (5 subtest), and FSIQ (11 subtest).
Wechsler Adult Intelligence Scale Third Edition (WAIS-III)
* 14 subtests for mental abilities
Wechsler Memory Scale (WMS-III)
* 16 subtests measuring short term and long term memory.

Question 18

Which of the two types of intelligence peaks earlier? (fluid vs. crystellized)

Answer 18

Fluid intelligence peaks earlier compared to crystallized intelligence

Question 19

Harstshorne & Germine conducted 4 experiments to compare the age of peak performance across 30 different cognitive tasks.

Explain experiment 1

Answer 19

Experiment 1: Renanalysis of Standardized Tests
Method:
* Published, demographically stratified normative data from two standardized tests (WAIS-III & WMS-III) were analyzed.
* N = 2,450 aged 16 and 89 years.

Question 20

What were the results from exp 1 in Hartshorne’s study?

Answer 20

• Earlier peaks for fluid intelligence compared to crystalized intelligence observed.
• Five tasks related to learned knowledge (vocabulary, information, comprehension, arithmetic, similarities) peaked later than other tasks.
• 4 tasks (STM-family pictures, STM-stories, WM-letter number sequencing, STM-word pairs) peaked in 20s
• 3 tasks (information, vocabulaty, comprehension) peaked around 50s

Question 21

Explain the methods of the second and third experiment from Hartshorne’s study

Answer 21

Experiment 2 and 3
Method:
* Large samples from internet-based methods. 10-71 years
* Focus on digit symbol coding, digit span, and vocabulary (they peaked in late teens, 20s, and 50 years)
Materials and procedure
* Digit symbol coding, visual working memory, verbal working memory (forward digit span) and vocabulary.
* 42 trials participants viewed an array of four nonnameable novel shapes. After a brief retention period, they determined whether a single probe shape was a member of the memory set.
* Exp 3 = mind-in eyes task

Question 22

What were the results from Hartshorne’s 2nd and 3rd experiment?

Answer 22

WM Digit symbol coding (20s)
WM Visual (20s)
WM Digit span (30s)
Emotion perception (40-50s)
Vocabulary (60s)

Question 23

What was the aim of experiment 4 from Hartshorne’s study?

Answer 23

Was the later peak performance on vocabulary for the internet based sample compared to WAIS-III due to cohort differences? (WAIS-III sample was from 2 decades ago).

Flynn effect: : IQ has increased steadily in modern times, possibly because of increasing amounts of time devoted to mental activity

Question 24

Describe the method used in experiment 4 of Hartshorne’s study

Answer 24

Method:
* Renanlysis of rsults from 1974-2012
* 10 question vocabulary test.
* Divided into three epochs: 1974-1987, 1988-1997, and 1998-2012

Question 25

What were the results of experiment 4 from Hartshorne’s study?

Answer 25

Results:
* Flynn effect was replicated: vocabulary scores increased across the epochs.
* Age related differences for the three epochs showed later peaks for each epoch
* Thus, it is likely that the later ages of peak performance in our data relative to the Wechsler data are at least partly due to generational differences, with later peaks seen in more recent generations

Question 26

What can be concluded from the 4 experiments done by Hartshorne?

Answer 26

• age-related changes in cognitive ability are considerably more heterogeneous and complex than the fluid-/crystalized-intelligence distinction suggest
• cross-sectional data may be subject to cohort effects:
• Our findings in Experiment 2 are consistent with the possibility that people born in 1945 have unusually large vocabularies, people born in 1980 have unusually good working memory, and people born in 1990 have unusually fast processing speed
• ages of peak performance for Digit Span and Digit Symbol Coding were similar in all data set
• One difference was observed between Internet-based and traditional samples: earlier age of peak performance for Vocabulary in the latter
• Due to Flynn Effect

Question 27

What are some practical implications of the study by Hartshorne?

Answer 27

• Cognitive tasks have different peaks, so there’s not one age at which individuals perform the best all cognitive tasks.
• This is important for clinicians when determining whether an individual is demonstrating signs of abnormal decline; they should consider age and type of cognitive task.

Question 28

What are some theoretical implications of the study from Hartshorne?

Answer 28

• Can enable theory development
• One factor in determining whether performance declines with aging is the degree to which different tasks allow for compensatory strategies.

Question 29

The results from Hartshorne’s study was not driven by cohort effects except for one task. Which task was that?

Answer 29

Vocabulary.

Question 30

What was the aim of Flensborg-madsen’s study?

Answer 30

examine whether age at attaining 12 motor developmental milestones was associated with IQ in adulthood and to evaluate the influence of a number of potential confounders and moderators on any observed associations

Question 31

Explain the method used by Flensborg’s study

Answer 31

Method:
* CPC over 8K mothers and their 9K + deliveries at the Copenhagen University Hospital from 1959 to 1961.
* Developmental milestones were obtained from mothers who kept diary records at different ages.
* Subsample from 1982 to 1994 – focused on prenatal and perinatal factors
* Final sample = 937 singletones

Question 32

What were the variables i nFlensborg’s study?

Answer 32

Variables
Participants vs. non-participants
Developmental milestones:
* 12 milestones
* Smiling and lifting head
* Rolling, crawling, sitting and grasping
* Standing and walking
WAIS

Question 33

What were the results from Flensborg’s study?

Answer 33

• Parent social status was the only differing variable between the two groups; lower mean social status for non-participants
• Age of attaining milestones was correlated with performance IQ; especially for mean milestones and standing and walking.
• Parity, gestational age, birthweight and birth length were all significantly associated with the overall mean of the 12 milestones
• Parental social status in infancy and the mother’s cigarette consumption during the last trimester of pregnancy were associated with mean level of intelligence in adulthood
• Sig associations between performance IQ and milestones (e.g. late attainment of lifting head on stomach, sitting without support, crawling, standing with support, walking without support, all correlated with low performance IQ.
• Only one milestone, ‘walking without support’, was significantly associated with Verbal IQ.
• The largest estimate for Full-scale IQ was found for ‘walking without support’
• in the low parental social status group, both the ‘mean of milestones’ in addition to all three factor means were significantly associated with intelligence, while there were no significant associations with these factors in the high parental social status group
• sits without support, stands without support, walks without support, walks with support, were all associated with Performance IQ in low parental social status.
• Only lifts head on stomach and sits without support were correlated with Performance IQ in the high parental social status.

Question 34

In Flensborg’s study:
associations were stronger, and generally more negative, in the offspring of lower social status parents, while the majority of associations with milestones were non-significant in the offspring of high social status pare
* Although the associations between infant developmental milestones and IQ were generally weak in this study, the results may have theoretical importance and in the low parental social status subsample, ‘walks without support’ accounted for as much as 9.2% of the variance in Performance IQ

What are the two explanations for these results?

Answer 34

(1) A causal explanation in which age of attainment of motor developmental milestones has a direct effect on the cognitive development and thereby IQ scores and,
* Relate to Piaget’s sensorimotor development and its importance for cognitive development
* Motor skills impact emotional, social, and communication development.
* It is also related to haptic perception.

(2) An explanation of achievement of milestones as being markers of underlying confounding factors influencing both motor and cognitive development
* The results may reflect unrecognized confounding factors (e.g. biological-neural systems, nutrition, psychological-parenting styles, education of parent).