3. What is Intelligence?
Intelligence
ability to learn from experience,
solve problems, and use knowledge
to adapt to new situations
4. How do we know intelligence
even exists?
Psychometricians specialize in measuring
psychological characteristics for intelligence and
personality. By using patterns of test scores, they
have found evidence for general intelligence as
well as for specific abilities
5. What is Intelligence?
General Intelligence (g)
factor that Spearman and
others believed underlies
specific mental abilities
measured by every task on
an intelligence test
6. Fluid and Crystallized Intelligence
• Aging and Intelligence
– Crystallized increases until
60
– Fluid peaks in adolescence
• Declining fluid intelligence
leads to decline in
Processing Speed
7.
8. What is Intelligence?
Factor Analysis
statistical procedure that
identifies clusters of related
items (called factors) on a
test
used to identify different
dimensions of performance
that underlie one’s total
score
9. Are There Multiple
Intelligences?
Savant Syndrome
condition in which a person otherwise limited
in mental ability has an exceptional specific
skill
computation
drawing
14. 14
Robert Sternberg
Sternberg agrees with Gardner, but suggests three
intelligences rather than eight.
1. Analytical Intelligence: Intelligence that is
assessed by intelligence tests.
2. Creative Intelligence: Intelligence that
makes us adapt to novel situations,
generating novel ideas.
3. Practical Intelligence: Intelligence that is
required for everyday tasks (e.g. street
smarts).
15. Intelligence and Creativity
Creativity
the ability to produce
novel and valuable
ideas
expertise
imaginative thinking
skills
venturesome personality
intrinsic motivation
creative environment
16.
17. 17
Emotional Intelligence: Components
Component Description
Perceive emotion
Recognize emotions in faces,
music and stories
Understand emotion
Predict emotions, how they
change and blend
Manage emotion
Express emotions in different
situations
Use emotion
Utilize emotions to adapt or be
creative
18. 18
Psychologists define intelligence testing as a
method for assessing an individual’s mental
aptitudes and comparing them with others using
numerical scores.
How is Intelligence Measured?
19. A Five-Minute IQ Test
1. Water lilies double in area every 24 hours. At the beginning of the
summer, there is one water lily on a lake. It takes 60 days for the
lake to become covered with water lilies. On what day is the lake
half-covered?
2. A farmer has 17 sheep. All but 9 break through a hole in the fence
and wander away. How many are left?
3. If you have black socks and brown socks in your drawer, mixed in a
ratio of 4 to 5. How many socks will you have to take out in order
to have a pair of the same color?
4. With a 7-minute hourglass, and an 11-minute hourglass, how can
you time the boiling of an egg for 15-minutes?
5. Washington is to one as Lincoln is to:
Five --or-- Ten --or-- Fifteen --or-- Fifty
20. How did you do?1. On day 59. Remember, it doubles every day.
2. Nine sheep. It is just a matter of careful reading.
3. Three socks. The ratio information is irrelevant.
4. Allow both glasses to drain simultaneously. As soon as
the 7-minute glass empties, flip it over (7 minutes have
expired). Then, flip it over again after the 11-minute glass
empties (11 minutes have expired). Fifteen minutes will
have passed when the 7-minute glass empties.
5. The answer is five. The task here is to realize that the
relation is no the sequence of their presidency but which
denomination of bill upon which each face appears.
21. Origins of Intelligence Testing
Alfred Binet and his
colleague Théodore
Simon practiced a
more modern form of
intelligence testing by
developing questions
that would predict
children’s future
progress in the Paris
school system.
22. Origins of Intelligence Testing
Mental Age
a measure of intelligence test performance
devised by Binet
chronological age that most typically
corresponds to a given level of
performance
child who does as well as the average 8-
year-old is said to have a mental age of 8
23. Origins of Intelligence Testing
Intelligence Quotient (IQ)
defined originally the
ratio of mental age (ma)
to chronological age (ca)
multiplied by 100
IQ = ma/ca x 100)
on contemporary tests,
the average performance
for a given age is
assigned a score of 100
26. Assessing Intelligence: Sample Items
from the WAIS
From Thorndike and Hagen, 1977
VERBAL
General Information
Similarities
Arithmetic Reasoning
Vocabulary
Comprehension
Digit Span
PERFORMANCE
Picture Completion
Picture Arrangement
Block Design
Object Assembly
Digit-Symbol Substitution
27. Assessing Intelligence
Standardization
defining meaningful scores by comparison with
the performance of a pretested “standardization
group”
Normal Curve
the symmetrical bell-shaped curve that describes
the distribution of many physical and
psychological attributes
most scores fall near the average, and fewer and
fewer scores lie near the extremes
28. The Normal Curve
130 and above
very superior
120-129 Superior
110-119 High
average
90-109 Average
80-89 Low
Average
70-79 Borderline
69 and below –
Extremely low
31. Assessing Intelligence
Reliability
the extent to which a test yields consistent
results
assessed by consistency of scores on:
two halves of the test
alternate forms of the test
retesting
32. Assessing Intelligence
Predictive Validity
success with which a test predicts the
behavior it is designed to predict
assessed by computing the correlation
between test scores and the criterion
behavior
also called criterion-related validity
33. The Dynamics of Intelligence
Intellectual Disability
a condition of limited mental ability
indicated by an intelligence score below 70
produces difficulty in adapting to the demands of
life
varies from mild to profound
Down Syndrome
retardation and associated physical disorders caused
by an extra chromosome in one’s genetic makeup
34. How Stable is IQ?
• Research suggests that intelligence is relatively
stable from early childhood on
• IQ scores tend to be fairly stable
– IQ test at 4 and a second at 17 - 13 points up or down
– IQ test at 8 and a second at 17 - 9 points up or down
– IQ test at 12 and a second at 12 - 7 points up or down
• The closer together in time that IQ tests are given…
the more consistent (stable) the scores.
35. Factors Influencing Intelligence
• The Child’s Influence
– Genetics
– Genotype–Environment Interaction
– Gender
• The Immediate Environment’s Influence
– Family Environment
– School Environment
• The Society’s Influence
– Poverty
– Race/Ethnicity
39. Heritability
the proportion of variation among
individuals that we can attribute to genes
variability depends on range of populations
and environments studied
42. Poverty
• Children from lower- and working-class homes average 10-15
points below their middle-class age mates on IQ tests
43. 43
Early Intervention Effects
Early neglect from caregivers leads children to
develop a lack of personal control over the
environment, and it impoverishes their intelligence.
Romanian orphans with minimal
human interaction are delayed in their development.
44. 44
Schooling Effects
Schooling is an experience that pays dividends,
which is reflected in intelligence scores. Increased
schooling correlates with higher intelligence scores.
To increase readiness for schoolwork,
projects like Head Start facilitate leaning.
Editor's Notes
Do we have an inborn general mental capacity (intelligence)? If so, can we quantify this capacity as a meaningful number?
Have you ever thought that since people’s mental abilities are so diverse, it may not be justifiable to label those abilities with only one word, intelligence?
In research studies, intelligence is whatever the intelligence test measures. This tends to be “school smarts.”
In research studies, intelligence is whatever the intelligence test measures. This tends to be “school smarts.”
In research studies, intelligence is whatever the intelligence test measures. This tends to be “school smarts.”
Preview Question 1: What argues for and against considering intelligence as one general mental ability?
Intelligence tests were developed for the practical function of selecting students for admission or placement in schools. Originally these tests were not based on any theory of intelligence. They defined intelligence as the ability to do well in school…. So IQ tests do measure intelligence.
What is a better definition… these do not allow us to define intelligence any better because we still have to define judge, comprehend, think rationally, etc…
general intelligence(g) Amental attribute that is hypothesized as contributing to the performance of virtually any intellectual task.
But what is this common element? If the subtests overlap in some way, what is the nature of the overlap? More than 50 years ago, Charles Spearman offered the obvious hypothesis—namely, that the common element is general intelligence, usually abbreviated with the single letter g. Spearman proposed that g is a mental attribute called on for virtually any intellectual task. It follows, therefore, that any individuals with a lot of g have an advantage in every intellectual endeavor; if g is in short supply, the individual will do poorly on a wide range of tasks.
Psychometric Approach
The measurement (metric) of individual differences in behaviors and abilities
George Spearman reported findings supporting the idea that performance on any test of mental ability was based on a single general ability factor that he termed “g”
Spearman also believed that performance on any test of mental ability required the use of a specific ability factor that he termed “s”
According to Spearman (1904) all intelligent abilities have an area of overlap, which he called “g” for general ability. Each ability also depends partly on an “s” factor for specific ability. According to Spearman… the “g” factor is the dominant ability when doing tasks. The “s” factors are the lesser abilities.
Psychologists are not in agreement on what “g” represents.
The correlations between mental tasks are due in part to their sharing of the same underlying processes. But… it is also due to the fact that these processes grow together, dependent on the same factor… health, nutrition, education, etc…
Fluid Intelligence
The ability to think on the spot and solve novel problems
The ability to perceive relationships
The ability to gain new types of knowledge
Crystallized Intelligence
Factual knowledge about the world
The skills already learned and practiced
Examples
Arithmetic facts
Knowledge of the meaning of words
State capitals
Fluid intelligence - reaches its peak before age 20 and then remains steady throughout life
Crystallized intelligence - continues to increase as long as people are active and alert
What does this mean?
A 20-year-old may be more successful than a 65-year-old at solving an unfamiliar problem but the 65-year-old will excel on problems in his or her area of specialization
generalintelligence(g) Amental attribute that is hypothesized as contributing to the performance of virtually any intellectual task.
But what is this common element? If the subtests overlap in some way, what is the nature of the overlap? More than 50 years ago, Charles Spearman offered the obvious hypothesis—namely, that the common element is general intelligence, usually abbreviated with the single letter g. Spearman proposed that g is a mental attribute called on for virtually any intellectual task. It follows, therefore, that any individuals with a lot of g have an advantage in every intellectual endeavor; if g is in short supply, the individual will do poorly on a wide range of tasks.
Fluid intelligence on tests is measured by:
The ability to assemble novel puzzles
The ability to determine the next entry in a series of numbers
The ability to identify which one of four objects is related to the others
Children who do well on one test of fluid intelligence usually do well on other tests of fluid intelligence
They may no necessarily perform well on tests of crystallized intelligence
The Theory of Multiple Intelligences
It seems that our measures of g—so-called general intelligence—may not provide as complete a measurement as we thought. The capacities measured by g are surely important, but so are other aspects of intelligence—including practical intelligence, emotional intelligence, and, according to some authors, social intelligence (see, for exam- ple, Kihlstrom & Cantor, 2000). Other authors would make this list even longer: In his theory of multiple intelligences, Howard Gardner argued for several further types of intelligence (Gardner, 1983, 1998):
Surveyed atypical populations, e.g. prodigies, idiot savants, autistic children, LD children.
Found jagged cognitive profile.
These profiles inconsistent with a unitary view of intelligence.
Question: does training in 1 area influence skills in other areas. For example, math training affect musical ability?
Another argument for Gardner’s theory comes from the study of people with so-called savant syndrome. These individuals have a single extraordinary talent, even though they’re otherwise developmentally disabled (either autistic or mentally retarded) to a profound degree. Some display unusual artistic talent. Others are “cal- endar calculators,” able to answer immediately (and correctly!) when asked questions such as “What day of the week was March 17 in the year 1682?”. Still oth- ers have unusual mechanical talents or remarkable musical skills—for example, they can effortlessly memorize lengthy and complex musical works (A. Hill, 1978; L. K. Miller, 1999).
Gardner’s claims have been controversial, partly because some of the data he cites are open to other interpretations (see, for example, Cowan & Carney, 2006; L. K. Miller, 1999; Nettelbeck & Young, 1996; Thioux, Stark, Klaiman, & Schultz, 2006). In addition, evidence indicates that several of the forms of “intelligence” Gardner describes are inter- correlated—and so if someone has what Gardner calls linguistic intelligence, they’re also likely to have logical-mathematical, spatial, interpersonal, and naturalistic intelligence. This obviously challenges Gardner’s assertion that these are separate and independent capacities (Visser, Ashton & Vernon, 2006).
Gardner (1993) defines intelligence as the ability to solve problems or to create products that are valued within one or more cultural settings.
Within this definition of intelligence, a variety of skills valued in different cultures and a history setting become objects of study.
Gardner proposes eight types of intelligences and speculates about a ninth one — existential intelligence. Existential intelligence is the ability to think about the question of life, death and existence.
Linguistics - sensitivity to the meanings and sounds of words, mastery of syntax, appreciation of the ways language can be used
Logical-Mathematical - Understanding of objects and symbols and of actions that be performed on them and of the relations between these actions, ability to identify problems and seek explanations
Spatial - capacity to perceive the visual world accurately, to perform transformations upon perceptions and to re-create aspects of visual experience in the absence of physical stimuli
Musical - Sensitivity to individual tones and phrases of music, an understanding of ways to combine tones and phrases into larger musical rhythms and structures, awareness of emotional aspects of music
Bodily-Kinesthetic - Use of one’s body in highly skilled ways for expressive or goal-directed purposes, capacity to handle objects skillfully
Interpersonal - Ability to notice and make distinctions among the moods, temperaments, motivations, and intentions of other people and potentially to act on this knowledge
Intrapersonal - access to one’s own feelings, ability to draw on one’s emotions to guide and understand one’s behavior, recognition of personal strengths and weaknesses
Naturalistic -- sensitivity and understanding of plants, animals, and other aspects of nature
Existential - sensitivity to issues related to the meaning of life, death, and other aspects of the human condition
Gardner (1993) defines intelligence as the ability to solve problems or to create products that are valued within one or more cultural settings.
Within this definition of intelligence, a variety of skills valued in different cultures and a history setting become objects of study.
Three of these are incorporated in most standard intelligence tests: linguistic intelligence, logical-mathematical intelligence, and spatial intelligence. But Gardner also argued that we should acknowledge musical intelligence, bodily-kinesthetic intelligence (the ability to learn and create complex patterns of move- ment), interpersonal intelligence (the ability to understand other people), intrapersonal intelligence (the ability to understand ourselves), and naturalistic intelligence (the ability to understand patterns in nature).
Gardner based his argument on several lines of evidence, including studies of patients with brain lesions that devastate some abilities while sparing others. Thus, certain lesions will make a person unable to recognize drawings (a disruption of spatial intelligence), while others will make him unable to perform a sequence of movements (bodily-kinesthetic intelligence) or will devastate musical ability (musical intelligence). Gardner concluded from these cases that each of these capacities is served by a separate part of the brain (and so is disrupted when that part of the brain is damaged), and therefore each is distinct from the others.
Preview Question 2: How do Gardner’s and Sternberg’s theories of multiple intelligences differ?
Preview Question 3: What is creativity, and what fosters it?
Expertise: A well-developed knowledge base.
Imaginative Thinking: The ability to see things in novel ways.
A Venturesome Personality: A personality that seeks new experiences rather than following the pack.
Intrinsic Motivation: A motivation to be creative from within.
A Creative Environment: A creative and supportive environment allows creativity to bloom.
Emotional intelligence is the ability to perceive, understand, and use emotions (Salovey and others, 2005). The test of emotional intelligence measures overall emotional intelligence and its four components.
Gardner and others criticize the idea of emotional intelligence and question whether we stretch this idea of intelligence too far when we apply it to our emotions.
Preview Question 6: When and why were intelligence tests created?
On day 59. Remember, it doubles every day.
Nine sheep. It is just a matter of careful reading.
Three socks. The ratio information is irrelevant.
Allow both glasses to drain simultaneously. As soon as the 7-minute glass empties, flip it over (7 minutes have expired). Then, flip it over again after the 11-minute glass empties (11 minutes have expired). Fifteen minutes will have passed when the 7-minute glass empties.
The answer is five. The task here is to realize that the relation is no the sequence of their presidency but which denomination of bill upon which each face appears.
In 1904, the French minister of public instruction appointed a committee with the specific task of identifying children who were performing badly in school and would benefit from remedial education. One member of this committee, Alfred Binet (1857–1911; Figure 11.1), played a pivotal role and had an extremely optimistic view of the project. As Binet saw things, the committee’s goal was both to identify the weaker stu- dents and then—crucially—to improve the students’ performance through training.
Intelligence Test
a method of assessing an individual’s mental aptitudes and comparing them to those of others, using numerical scores
For their task, Binet and the other committee members needed an objective way to assess each child’s abilities, and in designing their test, they were guided by the belief that intelligence is a capacity that matters for many aspects of cognitive functioning. This view led them to construct a test that included a broad range of tasks varying in content and difficulty: copying a drawing, repeating a string of digits, understanding a story, arithmetic reasoning, and so on. They realized that someone might do well on one or two of these tasks just by luck or due to some specific experience (perhaps the person had encountered that story before), but they were convinced that only a truly intelligent person would do well on all the tasks in the test. Therefore, intelligence could be measured by a composite score that took all the tasks into account. Moreover, they believed that the diversity of the tasks ensured that the test was not measuring
some specialized talent but was instead a measure of ability in general. Indeed, Binet put a heavy emphasis on this diversity, and even claimed that, “It matters very little what the tests are so long as they are numer- ous” (1911, p. 329).
In its original form, the intelligence test was intended only for chil- dren. The test score was computed as a ratio between the child’s “mental age” (the level of development reflected in the test performance) and his chronological age; the ratio was then multiplied by 100 to get the final score (Figure 11.2). This ratio (or quotient) was the source of the test’s name: The test evaluated the child’s “intelligence quotient,” or IQ.
IQ scores are also good predictors of performance outside the academic world. In fact, IQ scores are among the strongest predictors of success in the workplace, whether we measure success subjectively (for example, via supervisors’ evaluations) or objectively (for example, in productivity or measures of product quality; Schmidt &
Hunter, 1998, 2004; P. Sackett et al., 2008). Sensibly, though, IQ matters more for some jobs than for others. Jobs of low complex- ity require relatively little intelligence; so, not surprisingly, the cor- relation between IQ and job performance is small (although still positive) for such jobs. Thus, for example, there’s a correlation of roughly .20 between IQ and someone’s performance on an assem- bly line. As jobs become more complex, intelligence matters more, so the correlation between IQ and performance gets stronger (Gottfredson, 1997b). Thus we find correlations between .5 and .6 when we look at IQ scores and people’s success as accountants or shop managers.
Still other results also confirm the importance of IQ scores and make it clear that, if we measure someone’s IQ at a relatively early age, we can use that measure to predict many aspects of her life to come. For example, people with higher IQ scores tend, overall, to earn more money during their lifetime, to end up in higher-pres- tige careers, and even to live longer. Likewise, higher-IQ individuals are less likely to die in automobile accidents (Table 11.1) and less likely to have difficulty following a doctor’s instructions. (For a glimpse of this broad data pattern, see Deary & Derr, 2005;
Gottfredson, 2004; Kuncel et al., 2004; Lubinski, 2004; C. Murray, 1998.)We should emphasize that, as with the correlation between IQ and grades, all of these correlations between IQ and life outcomes are appreciably lower than 1.00. This reflects the simple fact that there are exceptions to the pattern we’re describing— and so some low-IQ people end up in high-prestige jobs, and some high-IQ people end up unsuccessful in life (with lousy jobs, low salaries, and a short life expectancy). These exceptions remind us that (of course) intelligence is just one of the factors influencing life outcomes—and so, inevitably, the correlation between IQ and life success isn’t perfect. Nonetheless, there’s still a strong statistical linkage between IQ scores and important life outcomes, making it clear that IQ tests do measure something
interesting and consequential.
WORLDWIDE IMPROVEMENT IN IQ SCORES
The impact of environmental factors on IQ scores is also undeniable in another fact. Around the globe, scores on intelligence tests have been gradually increasing over the last few decades, at a rate of approximately 3 points per decade. This pattern is known as the Flynn effect, after James R. Flynn, one of the first researchers to document this effect systematically. This improvement has been documented in many countries, including many developed (and relatively affluent) 75 nations and also relatively impoverished third world nations (Figure 11.19). (There’s also some suggestion that the improvement has now leveled off in some countries—Britain, for example—and may evenbe reversing; but it’s too soon to make a judgment on this point; Flynn, 2009.)
Could it be that people in the modern world are simply accumulating more and more information? If so, then the Flynn effect would be most visible in measures of crystal- lized intelligence. However, that’s not what the evidence shows. Instead, the effect is stronger in measures of fluid intelligence—such as the Raven’s Matrices—so it seems to be a genuine change in how quickly and flexibly people can think.
Some scholars suggest that this broad increase in scores is attributable to wide- spread improvement in nutrition and health care, and these factors surely do contribute to the Flynn effect in some parts of the world (for a study in Kenya, for example, see Daley et al., 2003). But we need some other explanation for why the effect is also evi- dent in middle-class populations in relatively wealthy countries (Flynn, 2009). One proposal is that this worldwide improvement is the result of the increasing complexity and sophistication of our shared culture: Each of us is exposed to more information and a wider set of perspectives than were our grandparents, and this exposure may lead to a sharpening of skills that show up in our data as an improvement in IQ.
Whatever the explanation, though, one point is clear: The Flynn effect cannot be explained genetically. While the human genome does change (a prerequisite, of course, for human evolution), it doesn’t change at a pace commensurate with this effect. Therefore, this worldwide improvement becomes part of the larger package of evidence documenting that intelligence can indeed be improved by suitable environ- mental conditions.
Reliability and Validity
Did Binet (and all who came after him) succeed in his aim of creating a test that truly measures intelligence? To find out, we need to evaluate the tests’ reliability and validity— key notions that we introduced in Chapter 1. As we described there, reliability refers to how consistent a measure is in its results and is often evaluated by assessing test-retest reliability. This assessment boils down to a simple question: If we give the test, wait a while, and then give it again, do we get essentially the same outcome?
Intelligence tests actually have high test-retest reliability—even if the two testoccasions are widely separated. For example, there is a high correlation betweenmeasurements of someone’s IQ at, say, age 6 and measurements when she’s 18.Likewise, if we know someone’s IQ at age 11, we can predict with reasonable accuracywhat his IQ will be at age 27 (see, for example, Deary, 2001a, 2001b; Deary,Whiteman, Starr, Whalley, & Fox, 2004; Plomin & Spinath, 2004). As it turns out,though, there are some departures from this apparent stability. For example, a substantial change in someone’s environment can cause a corresponding change in his
IQ score. We’ll return to this point later in the chapter, when we consider the effects of poverty (which can drive IQ downward) or schooling (which can increase IQ). Even so, if someone stays in a relatively stable and healthy environment, IQ tests are quite reliable.
What about validity? This is the crucial evaluation of whether the tests really meas- ure what we intend them to measure, and one way to approach this issue is to assess its predictive validity: If the tests truly measure intelligence, then someone’s score on the test should allow us to predict how well that person will do in settings that require intelligence. And here, too, the results are promising. For example, there’s roughly a .50 correlation between someone’s IQ and subsequent measures of academic per- formance (e.g., grade-point average; e.g., Kuncel, Hezlett, & Ones, 2004; P. Sackett, Borneman, & Connelly, 2008). This is obviously not a perfect correlation, because we can easily find lower-IQ students who do well in school, and higher-IQ students who do poorly. Still, this correlation is strong enough to indicate that IQ scores do allow us to make predictions about academic success—as they should, if the scores are valid.
IQ scores are also good predictors of performance outside the academic world. In fact, IQ scores are among the strongest predictors of success in the workplace, whether we measure success subjectively (for example, via supervisors’ evaluations) or objectively (for example, in productivity or measures of product quality; Schmidt &
generalintelligence(g) Amental attribute that is hypothesized as contributing to the performance of virtually any intellectual task.
The closer together in time that IQ tests are given… the more consistent (stable) the scores.
The changes that are seen here are likely due to random variation -- alertness at the time of test, his or her knowledge of the specific items on the test, etc…
Scores tend to increase in children who view academic achievement as important.
Scores tend to increase in children whose parents take an interest in their academic success and whose parents have firm but moderate disciplinary procedures.
Scores tend to decrease in children who view academic achievement as unimportant.
Scores tend to decrease in children whose parents are very stern or very lax and who show little interest in their academic success.
Fraternal twins raised together tend to show similarity in intelligence scores.
Identical twins raised apart show slightly less similarity in their intelligence scores.
The variation in intelligence test scores attributable to genetics. We credit heredity with 50% of the variation in intelligence.
It pertains only to why people differ from one another, not to the individual.
The more years children spend in poverty, the lower their IQs tend to be
Children from lower- and working-class homes average 10-15 points below their middle-class age mates on IQ tests
In many countries, children from wealthier homes score better on IQ test than children from poorer homes
The greater the gap in wealth in a country the greater the difference in IQ scores
Chronic inadequate diet can disrupt brain development
Chronic or short-term inadequate diet at any point in life can impair immediate intellectual functioning
Reduced access to health service, poor parenting, and insufficient stimulation and emotional support can impair intellectual growth
During the academic year -- schools provide children of all backgrounds with the same stimulating intellectual environment. Over the summer, children from low-SES families are less likely to have the kinds of experiences that would maintain their academic achievement.
Going to school more days of the year --- better for achievement scores. Attending school increases IQ scores and specific academic skills (such as increased mastery of reading and math).
Attending school makes children smarter
Children from families of low SES and those from families of high SES make comparable gains in school achievement during the school year
What about during summer break?
Children from families of low SES have a drop in achievement scores
Children from families of high SES have achievement scores that stay constant or rise slightly
