What is Special
1. 1. You can use the terms disability and handicap interchangeably. T/F
2. 2. The history
of special education began in Europe. T/F
students with disabilities was passed in the 1950s.
• Analyze the qualities that determine IQ tests’ usefulness and adequacy for measuring intellectual differences
All students with disabilities should be educated in special education classrooms. T/F
5. 5. Special education law is constantly reinterpreted. T/F
• Identify and relate the hierarchy of intellectual abilities posited by the psychometric approach to
Answers can be found at the end of the chapter.
• Explain how nature and nurture interact to influence intellectual differences in children.
• Differentiate stability, change, and modifiability in intelligence.
• Evaluate evidence that IQ scores can be improved in children through intervention.
1. The modern intelligence test was first developed to identify gifted children so that they
could receive advanced instruction. T/F
2. Children’s performance on measurements of nonverbal intelligence (for example, spatial
reasoning) is positively related to verbal intelligence (for example, vocabulary). T/F
3. Because genetic differences influence intellectual differences between children, the
impact of the environment is minimal. T/F
4. By age 6 or 7, a child’s IQ score is a fairly good predictor of subsequent IQ scores
throughout the child’s development. T/F
5. Generally speaking, if an intervention boosts a young child’s IQ score, the improvement
is permanent even after the intervention ends. T/F
Michael is a 6-year-old who is struggling both academically and socially. His parents are recently
divorced, and he is experiencing significant psychosocial stress. Michael had some issues prior to
the divorce, but his symptoms have been exacerbated. Michael’s teacher is unsure if the child’s
difficulties in school stem from problems coping with the divorce or from cognitive delays that
make it difficult to keep pace with the other children. As part of the assessment procedure, the
school psychologist, Dr. Williams, administers an intelligence test to measure Michael’s cognitive
functioning. Intelligence test performance is a factor in determining whether a child is eligible
for specialized services (Individuals with Disabilities Education Improvement Act, 2004).
Questions on the intelligence test ask Michael to remember a string of randomly arranged digits
(“Repeat after me: ‘3-1’”). Others require him to arrange puzzle pieces or solve addition and subtraction problems. During testing, the 6-year-old seems tired or perhaps unmotivated. However,
Williams avoids providing minor hints and suggestions to prompt Michael and help him out a
bit. When the test is over, Williams tallies the child’s correct answers and determines how his
scores compare with a large sample of same-age children. He will look for patterns that indicate
areas of relative weakness and strength.
At the end of the assessment, Williams faces a dilemma. Michael’s outcome on the intelligence
test finds him right on the borderline for placement in a special education program.
Questions to Think About
1. Should Williams have provided some hints to help the child during testing? Explain
2. Do you believe an intelligence test would provide enough information to make a
decision about Michael’s placement? Why or why not? If not, what other information
should Williams gather? Explain your answer.
3. Michael is a very young child—how should his age factor into the decision to place
him in a special education program?
4. Would the divorce impact Michael’s cognitive functioning? If so, how?
Differences in children’s intelligence predict later income, occupational status, and educational attainment in adulthood (Firkowska-Mankiewicz, 2011). Children’s intelligence is
even related to later health and length of life (Batty, Deary, & Gottfredson, 2007)! This broad
influence raises a number of questions. What is intelligence? How is it measured? Why do
children differ in intelligence? What steps, if any, can be taken to increase intelligence? These
questions are heavily researched, and we will address them and other related questions in
Although there is no single, universally agreed-upon definition, many contemporary psychologists would agree with the description of intelligence as: “The ability to reason, plan, solve
problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience” (Gottfredson, 1997, p. 13; see also Kranzler & Floyd, 2013). Another definition is that
intelligence is the “ability to understand complex ideas, to adapt effectively to the environment, to learn from experience, to engage in various forms of reasoning, to overcome obstacles by taking thought” (Neisser et al., 1996, p. 77).
Notice that these definitions include cognitive processes that are broadly applicable, like
reasoning, abstract thinking, and learning from experiences. Processes like reasoning and
learning from experiences are evident every day in multiple settings. As you reread the definitions, notice also how the cognitive processes relate to schooling. As we will see, from the
beginnings of modern intelligence testing, the concept of intelligence has been closely tied to
Intelligence can also be defined as an ability or set of abilities that extend beyond those
found in the previous definitions, and we will discuss various theories of the nature of intelligence in Section 10.2. For now, however, we will work with a conception of intelligence
that is tied to the definitions we have just presented. These definitions are widely accepted
and underlie most tests of intelligence and contemporary research on the subject (Nisbett
et al., 2012).
Core Themes, Intelligence, and Individual Differences
The nature and measurement of intelligence is a broad, expansive topic. The four overarching themes in our text help us organize our understanding of the wide-ranging material. The
themes also place the study of intelligence into context by relating the material to topics and
ideas we have encountered in previous chapters.
Nature and nurture. The extent to which intellectual differences are related to genes or environment has generated considerable theorizing and large-scale investigations over the years.
Consequently, the nature–nurture theme is evident throughout this chapter. Recall from Chapter 1 that the nature–nurture theme is often raised in the context of why people differ from
one another. This concern with individual differences, idiographic development, is a focus as
we explore why children differ from one another in intelligence.
Performance and competence. Second, intelligence testing is intended to accurately measure
differences in children’s intellectual competencies. We will address whether intelligence tests
are considered fair and accurate. Such concerns are related to the performance–competence
theme of our book. Are the test scores really measuring intelligence (competence), or do the
scores reflect, to some extent, performance limitations (for example, low motivation or cultural misunderstandings)?
Continuity and discontinuity. Generally, intelligence testing is concerned with stable differences among individuals, rather than stage-like cognitive changes that occur within an
individual (Miller, 2012a). Consequently, in this chapter we primarily focus on the question
of whether there is continuity in intellectual differences. We address whether intellectual
differences are relatively stable and continuous during childhood, whether children’s intelligence fluctuates during development, and whether childhood intelligence predicts later
Domain general and domain specific. Our fourth theme is concerned with whether cognition
is better characterized as domain general or domain specific. In this chapter, we will see evidence indicating that intelligence is a general ability that cuts across a wide variety of cognitive domains. We will also encounter a theory that suggests there are many intelligences, each
somewhat specific to a particular domain.
10.1 Intelligence Tests
The results of intelligence tests can have a powerful impact on a child’s educational future, as
we saw in the case study. Results can influence whether a child is placed in special education
classes. Sometimes children are tested for placement into accelerated education programs.
Intelligence tests are also used for clinical assessments; for instance, the results of a test can
help determine if a child who recently suffered a head injury is experiencing cognitive impairments as a result of the injury.
The influence of intelligence testing naturally raises two questions: How is intelligence measured, and how do we know if an intelligence test is dependable and accurate? Our focus on
testing provides a foundation for subsequent sections in which we discuss theories of intelligence, its stability and change, and the factors that influence individual differences in intelligence. First, however, we will describe how intelligence tests developed and how they are
The Development of Intelligence Testing
The French Third Republic passed laws in the early 1880s making school mandatory and free
for all 6- to 13-year-old children (Nadeau & Barlow, 2010). The inclusiveness of the French
education system meant that classrooms were filled with children of varying backgrounds
and skill levels. Soon government officials were faced with the dilemma of how to effectively
handle children who had difficulty keeping pace with their peers.
An instrument that could accurately identify at-risk children was sought, particularly when
concerns arose over the accuracy and impartiality of a school official’s or parent’s opinion.
Alfred Binet was a French psychologist who, along with his collaborator Theodore Simon,
set out to resolve the problem by creating an effective measurement of children’s intellectual capabilities (Binet & Simon, 1916; Nicolas, Andrieu, Croizet, Santioso, & Burman, 2013;
Binet’s test ultimately contained three distinctive features still found in many intelligence
tests (Siegler, 1992). First, it measured high-level cognitive abilities like memory, vocabulary,
and reasoning that clearly related to the child’s schoolwork (Binet & Simon, 1916). These
abilities are closely related to the definitions of intelligence presented in the previous section.
Second, a single composite score summed across different cognitive subtests was used to
estimate a child’s intelligence (Siegler, 1992). As we will see, this feature of intelligence testing remains influential. It also brings to the forefront the question of whether intelligence is
really a singular entity. We discuss theories that address whether intelligence is made up of
one or numerous entities in Section 10.2.
Third, test items were arranged in sequence from less to more difficult. This arrangement
allowed test administrators to determine how far children could progress before reaching
their ceiling. A ceiling is typically established when a child misses a specified number of items.
Once the child’s ceiling was established, the tester could then compare it with the average
ceiling reached by same-age peers. In our case study at the beginning of the chapter, Michael’s
score is low because he missed items that other children his age typically answer correctly. In
other words, Michael did not progress through as many items as his peers.
IQ Tests Today
The conventional scoring method used to express intelligence is known as the intelligence
quotient (IQ). Conceptually, an IQ score is derived by comparing an individual’s performance
(called a “mental age”) against the typical performance of those who are the same chronological age. In this formulation, IQ = mental age ÷ chronological age (Stern, 1914). For instance,
if an 8-year-old’s performance is at the level of a typical 10-year-old, she would have a score
of 1.25 (that is, 10 ÷ 8). Conventionally, average IQ scores are set at 100 (Kranzler & Floyd,
2013). Thus, 10 ÷ 8, (or 1.25) multiplied by 100 results in an IQ score of 125.
Figure 10.1 illustrates the types of items found on commonly used intelligence tests. These
tests generally have (a) subtests that measure cognitive abilities (for example, math, vocabulary, math, and reasoning) and (b) a full-scale composite score that is derived from subtest
Figure 10.1: Sample items found on IQ tests
Examples of questions found on commonly administered intelligence tests. Note that items assess
various abilities such as verbal comprehension (Information; Vocabulary) and reasoning (e.g., Block
Design, Picture Completion).
Typical IQ Subtests
Information On what continent is Argentina?
Arithmetic If four toys cost six dollars,
how much do seven cost?
Find the missing piece from the six
Vocabulary What does “debilitating” mean?
Comprehension Why are streets usually numbered
Picture Completion Indicate the missing part from an
Block Design Use blocks to replicate a two-color
Object Assembly Assemble puzzles depicting
Coding Using a key, match symbols with
shapes or numbers.
Picture Arrangement Reorder a set of scrambled picture
cards to tell a story.
Similarities In what way are dogs and rabbits
Source: Flynn, J. R. (2007). Solving the IQ puzzle. Scientific American Mind, 18(5), 24–31.
Some commonly administered intelligence tests are summarized in Table 10.1.
Table 10.1: Representative IQ tests administered to children
2 to 85+
• Ten subtests assess cognitive processes such as working memory,
general knowledge, quantitative and spatial reasoning, and
• Subtests are administered in both verbal and nonverbal forms.
• All 10 subtests are scored. The full-scale IQ score combines all 10
Table 10.1: Representative IQ tests administered to children (continued)
and Primary Scale of
2 to 7
Scale for Children,
6 to 16
4 to 90
• Ages 2 to 3 assessed by three subtest areas of verbal
comprehension, spatial knowledge, and working memory; testing
for ages 4 to 7 also includes processing speed and reasoning
• Subtest scores and full-scale IQ.
• Ancillary scores enhance utility for special cases, such as the
assessment of school readiness or suspected language delays.
Ancillary scores include a cognitive proficiency score (working
memory and processing speed) indicating informationprocessing efficiency.
• Five subtests assess verbal comprehension, spatial knowledge,
working memory, processing speed, and reasoning.
• Subtest IQ scores and full-scale IQ
• Ancillary index scores provide additional information relevant to
clinical situations (such as a nonverbal index score for children
with autism) and school achievement (such as a quantitative
• Provides a quick screening measure for identifying children
at academic risk or those eligible for enriched educational
• Three subtests. Two measure verbal knowledge such as
vocabulary, and one measures nonverbal knowledge related to
reasoning about novel problems (that is, choosing which of five
pictures best matches the concept in a target picture).
• Subjects receive verbal, nonverbal, and IQ composite scores.
Sources: Bain & Jaspers, 2010; Kaufman & Kaufman, 2004; Raiford & Coalson, 2014; Roid, 2003; Wechsler, 2014.
As noted earlier, a child’s IQ score is determined by comparing his or her performance with
same-age peers. The comparison group is called the normative sample. A normative sample
is a group of individuals who are representative of the larger population. In order to be representative, the sample must be inclusive and proportionately reflect the different backgrounds
and ethnicities within a population. To illustrate, the normative sample for the Stanford-Binet
(fifth edition) totaled nearly 5,000 individuals and was chosen to match demographic information derived from the 2000 U.S. Census (Roid, 2003).
IQ scores in normative samples generally form a normal distribution (Gottfredson, 2008).
This means scores within the sample most frequently occur in the middle—the overall average—and then occur less and less frequently as scores deviate further and further from the
average (see Figure 10.2). Recall that most IQ tests are quantified so that the average score is
100 (Kranzler & Floyd, 2013). Thus, when a child is said to have “above average” intelligence,
this means, in a literal sense, that the score is higher than 100, the average score of children
the same age.
Figure 10.2: Normal distribution
Scores within a normal distribution tend to cluster toward the middle (average) in their frequency. As
scores deviate from the average, they occur with less and less frequency. IQ scores typically follow a
A standard deviation measures the extent that scores vary from the average. Conventionally, IQ
scores change by 15 points for every standard deviation above or below the average (Kranzler
& Floyd, 2013). In other words, IQ scores that are one standard deviation above the average are
115, while scores one standard deviation below the average are 85. When scores are normally distributed, 68% of scores fall within one standard deviation of the mean, and 95% of the scores fall
within two standard deviations (see Figure 10.2). Thus, 95% of IQ scores typically fall between 70
Scores that are two standard deviations below the mean (scores of 70 or lower) indicate an
intellectual disability (Prifitera, Saklofske, & Weiss, 2008). An intellectual disability is characterized by “significant limitations both in intellectual functioning and in adaptive behavior”
that originate before age 18 (Schalock, Luckasson, & Shogren, 2007, p. 118).
The transition to school is difficult for children diagnosed with intellectual disability—the
cognitive and behavioral expectations of schooling can often exceed the child’s readiness.
Social skills (for example, appropriate expression of feelings) and self-regulation skills can
positively contribute to the ability of 5- to 6-year-old children with an intellectual disability
to adapt to school (McIntyre, Blacher, & Baker, 2006). Consequently, early interventions that
focus on social and behavioral competencies may be useful in smoothing the transition to
schooling for children who have an intellectual disability.
Children identified as gifted (also referred to as “talented”) exhibit extraordinary intellectual
ability, promise, creativity, and motivation (McClain & Pfeiffer, 2012). Children are generally
identified as “gifted” or “talented” in intelligence as their IQ scores approach 130 (McClain
& Pfeiffer, 2012). Other measures, such as teacher ratings for mo ...
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