Understanding Intelligence: Theories and Processes

Intelligence as a Single Trait

• "General intelligence," or g, was conceptualized by Carroll in 2005 and Spearman in 1927.
• Evidence for g includes correlations with cognitive performance, educational success, real-world achievement, brain function, structure, and general knowledge.

Intelligence as a Few Abilities

• Fluid intelligence (Cattell, 1963) is tested through abstract reasoning tasks.
• Fluid intelligence is closely linked to processing speed, working memory, and attentional control (Geary, 2005).
• Fluid intelligence peaks in young adulthood and declines with age.
• Crystallized intelligence (Cattell, 1963) involves the accumulation of knowledge, facts, and vocabulary.
• Crystallized intelligence depends on long-term memory and verbal ability.
• Crystallized intelligence steadily increases throughout life.

Intelligence as Numerous Cognitive Processes

• Research has identified multiple cognitive processes that contribute to intelligence,
• These include perception, memory, attention, encoding, generalizing, and reasoning & problem-solving (Siegler et al., 2003).

Three Stratum Theory of Intelligence (Carroll 1993; 2005)

• General intelligence (g) sits at the top.
• Fluid intelligence includes sequential reasoning, induction, and quantitive reasoning.
• Crystallized intelligence includes printed language, language comprehension, and vocabulary knowledge
• General memory & learning includes memory span and associative memory.
• Broad visual perception includes visualization, spatial relations, and closure speed.
• Broad auditory perception includes speech sound discrimination, and general sound discrimination.
• Broad retrieval ability includes creativity, ideational fluency, and naming facility.
• Broad cognitive speediness includes rate of test taking, numerical facility, and perceptual speed.
• Processing speed includes simple reaction time, choice reaction time, and semantic processing speed.

Measuring Intelligence

• Critics of IQ tests argue current tests measure a narrow range of abilities and are culturally biased.
• They argue that reducing intelligence to a single IQ score oversimplifies cognitive abilities and raises ethical concerns.
• Advocates argue IQ tests are the best tool for predicting life outcomes like academic and career success.
• IQ tests help identify children who may need special education or gifted programs.
• Alternative methods may introduce greater bias.

Wechsler Intelligence Scale for Children (WISC-V)

• (Cormier et al., 2016) is based on Carroll's Three-Stratum Theory.
• WISC-V measures general intelligence (g) for an overall IQ score.
• WISC-V measures moderately general abilities across five key areas: verbal comprehension, visual-spatial processing, working memory, fluid reasoning, and processing speed.

Intelligence Quotient (IQ)

• Average IQ is set at 100.
• IQ scores follow a normal distribution (bell curve).
• I.e. 68% of people score between 85 and 115 (within 1 standard deviation of the mean).
• 2% of people score above 130, designated as gifted.
• Less than 1% of people score below 55.
• IQ remains stable over time.
• IQ scores are predictors of educational, occupational success (Brown et al., 2021), health and well-being.

Other Predictors of Success

• Characteristics of success include self-discipline (Makel et al., 2016) and practical intelligence (Cianciolo et al., 2006; Sternberg, 2003).
• Bronfenbrenner's (1993) bioecological model includes three factors:
• The Child's Individual Traits, comprised of genetic predispositions and personal experiences.
• Immediate Environment, consisting of direct influences like family, school, teachers, and peers.
• Wider Environmental Factors involving indirect influences like cultural values, economic conditions, and government policies.

Genetics & Intelligence

• Genetic influence on IQ is moderate in early childhood, but becomes substantial by adolescence and adulthood (Plomin & Deary, 2015).
• There is a tendency that adopted children's IQ scores become more similar to their biological parents' scores over time, even without contact.
• Their resemblance to adoptive parents decreases (Plomin et al., 1997).
• Intelligence depends on small contributions from many genes interacting in complex ways.

Gene-Environment Interactions (Scarr, 1992)

• Passive Effects: parents provide environments that match children's predispositions.
• Evocative Effects: children influence their environment, eliciting certain responses.
• Active Effects: as children grow, they choose environments that fit their preferences.

The Influence of the Home

• Home Observation for Measurement of the Environment (HOME) measures safety, organization, book availability, parent-child interaction, and parental support (HOME) (Bradley and Caldwell, 1979).
• Children's IQ scores are positively correlated with HOME scores at all ages.
• When HOME scores stay stable, IQ scores tend to be stable, conversely, when HOME scores change, IQ scores also change in the same direction (Totsika & Sylva, 2004).

Role of SES & School

• The impact of genes and environment on shaping intelligence varies by family income level.
  • Environment plays a larger role than genetics does for low-income families.
  • Genetics has a stronger influence than shared environment does for middle- and high-income families.
• These differences are noticeable as early as age 2.
• IQ and achievement test scores increase during the school year but tend to remain stagnant—or even decline—during summer break (Huttenlocher, Levine, & Vevea, 1998).

Effects of Poverty

• Poverty affects intellectual development (Korenman, Miller, & Sjaastad, 1995).
• Poor nutrition arises because chronic undernutrition in early childhood can impair brain development.
• Limited access to healthcare because more health issues leads to higher school absenteeism, reducing learning opportunities.
• Family stress and instability because of emotional distress, it can make it harder for children to concentrate.
• Fewer educational resources because they have less access to books and tutoring, in addition to fewer enriching activities.

Influence of Society

• Flynn effect: The steady rise in average IQ scores across many countries from 1930 to 2010.
• In the U.S., IQ scores increased by about 10 points during this period (Flynn & Weiss, 2007).
• Genetics remains unchanged and therefore environment shifts.
• Better living conditions include causes (Lynn, 2009; Eppig, Fincher, & Thornhill, 2010) and a shift toward abstract thinking.
• Some studies now suggest a reverse Flynn Effect (Dworak, Revelle, & Condon, 2023).

Risk Factors

• Risk factors include the head of household being unemployed or having a low-status job (Sameroff, 1993).
• Other risk factors include the mother not completing high school, the absence of a father figure, a high number of recent stressful life events, maternal mental health issues, and negative mother-child interactions.
• Sameroff and team tracked the IQ scores and environmental risks.
• Zero risk factors correlate with an average IQ of 115 and six or more risk factors correlate to the opposite effect, with an average IQ of 85-a 30-point gap.
• Concluded, total number of risk factors was the best predictor of IQ.

Alternative Perspectives on Intelligence

• Gardner's Theory of Multiple Intelligences include :
• Linguistic, Logical-mathematical , Spatial, Musical, Naturalistic , Body-kinesthetic, Intrapersonal, and Interpersonal intelligence.
• Sternberg's Theory of Successful Intelligence:
• Analytical: linguistic, math, spatial abilities
• Practical: ability to handle everyday problems and decision-making
• Creative: adaptation & flexibility

Reading Development (Chall 1979)

• Stage 1 (Birth to Grade 1): Recognizing alphabet and developing phonemic awareness
• Stage 2 (Grades 1 and 2): acquiring phonological recoding skills ("sounding out")
• Stage 3 (Grades 2 and 3): gaining fluency in simple materials
• Stage 4 (Grades 4 through 8): transitioning from learning to read to reading in order to learn new things
• Stage 5 (Grades 8 through 12): adolescents acquire reader skills, allowing understanding from multiple perspectives within texts.

Reading Development

• Exposure to books doesn't directly affect early literacy skills (Evan et al., 2000).
• Child's interest + parents' interest and expectations positively affects early literacy (Martini & Senechal, 2012).
• One of the strongest predictors of later reading success is phonemic awareness.
• It is more strongly correlated with reading success than IQ score, or socioeconomic status (SES).
• Teaching phonemic awareness at ages 4 and 5 has been shown to improve reading and spelling (Lonigan, 2015).

Comprehension

• Early Grades is when skillful decoding is the best predictor of reading comprehension. -Children need to be able to decode words accurately for texts in order to understand them.
• Post-Grade 4 is when listening comprehension becomes even better predictor of reading comprehension (Castles, Rastle, & Nation, 2018).
• Factors that influence comprehension include metacognition and content Knowledge.
• There is a compounding relationship: reading begets reading.

Writing Development

• Early writing behaviors include drawing symbols that resemble letters and scribbling in sequences.
• When children write more markings for words, they represent multiple objects (i.e. "forest”) than for single objects (i.e. “tree”) (Levin & Korat, 1993).
• Writers must juggle multiple goals which can be divided to low and high level goals.
• Lo-level goals consist of mechanics of writing i.e. (forming letters, spelling, grammar).
• High-level goals consist of structuring ideas, forming arguments, and organizing content.

Mathematics Development

• Common strategies include counting from the larger addend and decomposition when breaking a problem into smaller, manageable parts.
• Developmental Progression (Berteletti et al., 2010; Geary et al., 2007; Thompson & Opfer, 2010): -Ages 3-6: improving understanding of numbers 1-10. -Ages 6-8: children grasping of numbers 1-100. -Ages 8-12: ability to understand numbers 1-1000
• Math achievement varies across cultures due to differences in educational emphasis & quality of instruction, and time spent practicing math.

Mathematics Anxiety

• Onset & Prevalence: Starting in Grade 1, and it can persist into adulthood.
• Affects a large portion of university students (25%) (Beilock & Willingham, 2014).
• Girls report higher anxiety overall (Halpern et al., 2007; Devine et al., 2012).
• Parental Influence: -Parents with math anxiety can pass it to their children, and helping with parental homework can worsen anxiety (Berkowitz, 2015; Maloney, 2015).
• Means for reducing Math Anxiety through worked examples is a confidence builder and improve stress, ultimately improving performance (Ramirez & Beilock, 2011).

COVID & Learning

• The pandemic caused severe disruptions especially affecting low-income students.
• Students in lower-income school districts experienced twice the learning decrease that students in wealthier districts did (Kane & Reardon, 2023).
• Losses were seen in reading, math, history, and civics.
• Contrast with Sweden (Hhallin et al., 2022).
• Schools were kept open and showed no significant learning loss.