2.8 Intelligence

2.8 Intelligence

Definition

• Intelligence is defined as a mental quality consisting of the ability to learn from experience, solve problems, and use knowledge to adapt to new situations.

Emotional Intelligence

• Emotional Intelligence refers to the ability to perceive, understand, manage, and use emotions effectively.

Brain Size and Intelligence

Big Brain = Smart Brain?

• There is a complex relationship between brain size and intelligence.

  • Having a larger brain does not always guarantee higher intelligence.

  • Yet, research indicates a correlation exists between the size of the frontal and parietal lobes and higher intelligence scores.

Quick Brain = Smart Brain?

• Neural processing speed shows a correlation with higher intelligence scores.

  • The nature of this relationship (cause or correlation) remains under investigation.

Influences on Intelligence

Heritability

• Heritability refers to the portion of variation among individuals in intelligence that can be attributed to genetic differences.

Genes and Intelligence

• Studies indicate that:

  • Identical twins score more similarly on intelligence tests than fraternal twins (Lykken, 1999).

  • Identical twins exhibit similar brain structure and function (Deary, 2009).

  • Adopted children’s mental similarities with their adoptive families decline to near zero by adulthood (McGue, 1993).

Who do Adopted Children Resemble in Verbal Ability?

• Findings indicate parallels in verbal abilities:

  • Children resemble their birth parents more closely than their adoptive parents in verbal ability at ages 3 and 6.

Environmental Influences on Intelligence

• Extreme neglect has been shown to significantly diminish innate intelligence (Nelson, 2009).

• A correlation exists between poverty and lower verbal intelligence levels (Tuerk, 2005).

  • Notably, there is no scientific backing for claims about "Baby Einstein" or other educational programming for young children (DeLoache et al., 2010).

Types of Tests Related to Intelligence

Achievement Test

• An achievement test is designed to assess what a person has learned.

Aptitude Test

• An aptitude test aims to predict a person's future performance.

  • Aptitude is defined as the capacity to learn.

Theories of Intelligence

Spearman’s General Intelligence Theory

• Suggests that intelligence can be expressed by a single factor known as g, encompassing multiple cognitive abilities.

Sternberg’s Triarchic Intelligence Theory

Three Types of Intelligence:

1. Analytical Intelligence:

   • Involves problem-solving capabilities and academic skills, focusing on finding the one correct answer.

2. Creative Intelligence:

   • Ability to react adaptively to novel situations and generate innovative ideas.

3. Practical Intelligence:

   • Applies knowledge to everyday tasks and real-world scenarios, often referred to as ‘street smarts’.

Measuring Intelligence

Psychometrics

• Psychometrics is the field of psychology dedicated to testing, measuring, and assessing various psychological behaviors and activities, including intelligence.

Intelligence Test

• An intelligence test assesses an individual’s mental aptitudes and compares them with others through numerical scores.

Mental Age

• A concept developed by Alfred Binet to measure intelligence test performance, indicating the chronological age that corresponds to a specific level of performance.

Intelligence Quotient (IQ)

Original Definition

• IQ was originally defined as the ratio of mental age (ma) to chronological age (ca) multiplied by 100:
  $IQ = \frac{ma}{ca} \times 100$

Contemporary Understanding

• In modern intelligence assessments, the average score for a given age is set at 100, with scores reflecting relative performance.

Prominent Intelligence Tests

Wechsler Adult Intelligence Scale (WAIS)

• The WAIS is the most widely used intelligence test, evaluating both verbal and performance (nonverbal) subjects.

Stanford-Binet Test

• This is the widely adopted American revision of Binet’s intelligence test, designed to identify children requiring special educational attention.

Standardization

• Standardization involves defining uniform testing procedures and creating meaningful scores by comparing outcomes with those from a pretested group.

Normal Curve

• The normal curve is a symmetrical, bell-shaped curve describing the distribution of many physical and psychological attributes, where most scores cluster around the average, with fewer scores at the extremes.

Gender Differences in Intelligence

Overall Findings

• Research indicates minor differences in average IQ scores:

  • Girls’ average score: 100.6

  • Boys’ average score: 100.5 (Deary et al., 2005).

Specific Skills

• Girls tend to score higher in:

  • Spelling

  • Verbal fluency

  • Locating objects

  • Detecting emotions

  • Sensitivity to touch, taste, and color.

• Boys excel in:

  • Spatial ability

  • Complex math problems

  • Boys show greater variation, being over-represented in both Special Education and the highest SAT scores.

Racial/Ethnic Differences in Intelligence

• Research indicates there are observable differences in intelligence across races/ethnicities without a straightforward explanation.

  • Most researchers attribute these disparities to environmental factors.

The Flynn Effect

• The Flynn Effect observes a steady increase in performance on IQ tests throughout the last century, suggesting environmental factors (such as nutrition and education) play a significant role in intelligence.

Gardner’s Multiple Intelligence Theory

• Howard Gardner proposed that intelligence encompasses multiple abilities rather than being a single measure. The types of intelligence include:

  • Linguistic

  • Naturalistic

  • Logical-mathematical

  • Interpersonal

  • Spatial

  • Intrapersonal

  • Musical

  • Bodily/Kinesthetic

Evaluating Test Quality

Reliability

• Reliability refers to the extent to which a test produces consistent results.

Test-Retest Reliability

• A method of measuring reliability by administering the same test to different groups over time.

  • A strong correlation in scores indicates higher reliability.

Split-Half Reliability

• A method for assessing reliability by dividing a test into two halves and comparing the results.

  • A strong correlation between the two halves indicates greater internal consistency (though some argue this is not a compelling measure).

Validity

• Validity refers to the extent to which a test measures what it intends to measure.

Construct Validity

• The degree to which a test accurately measures or predicts what it is supposed to.

  • Particularly important for conceptual constructs that are difficult to quantify.

Content Validity

• The adequacy with which a test represents all aspects of what it aims to measure, ensuring all items in the test are relevant and appropriate.

Predictive Validity

• The success with which a test can predict the behavior it intends to predict, measured by the correlation between test scores and actual outcomes.

Discussion on IQ Test Bias

Scientific Consensus

• While scientifically there appears to be no bias in IQ tests, potential cultural biases may exist.

Stereotype Threat

• Defined as a self-fulfilling concern that one will be evaluated based on a negative stereotype.

  • Study (Sackett, 2008): Black students reminded of their racial identity during testing performed worse than those who were not.

Stereotype Lift

• Described as a performance boost experienced by groups that are not subject to negative stereotypes.

Aging and Intelligence

Overview of Findings

• Cross-sectional testing indicates a significant decrease in verbal intelligence with age.

• Longitudinal testing shows that intelligence remains more stable, peaking around ages 50-60 without facing dramatic decline.

General Trends

• As individuals age, there tend to be declines in reasoning, spatial visualization, memory, and processing speed.

Types of Intelligence

Crystallized Intelligence

• Refers to the accumulated knowledge and verbal skills; typically increases with age.

  • Includes all learned knowledge.

Fluid Intelligence

• Represents the ability to reason speedily and abstractly; generally decreases during late adulthood.

  • Reflects one's ability to think critically and adaptively.

Extremes of Intelligence

Intellectual Disability

• Defined as a condition of limited mental ability, indicated by an IQ score of 70 or below, associated with difficulties in adapting to life demands.

Down Syndrome

• A condition resulting in mild to severe intellectual disability and physical disorders, caused by an extra copy of chromosome 21.

Savant Syndrome

• Describes individuals with limited mental ability who possess exceptional specific skills (for example, in computing or drawing).

  • Example: Savant Syndrome showcased in various TED Talks.

Differences in Intelligence

• Studies show that children who took the SAT at 13 and scored in the top 1% were more likely to eventually publish novels, secure patents, and obtain doctoral degrees.

• This raises questions about whether intelligence differences should lead to different educational strategies.

Other Influencing Factors

Growth Mindset

• Defined as the belief that an individual's abilities can be improved through effort, learning, and persistence.

Fixed Mindset

• A fixed mindset comprises the belief that intelligence is a static trait that cannot be changed or developed further.