h verbs that clearly state the observable action that students will be able to carry out at the end of instruction. For example, rather than stating that a student should ‘‘know’’ certain material, a good instructional objective may state that the student should be able to define, list, label, or match specific concepts from the material. Rather than stating that a student should be able to ‘‘analyze’’ the material, a good instructional objective may state that the student should be able to diagram, differentiate, question, or summarize the material. In the study of instructional objectives, several lists of verbs have been developed that teachers can use when writing objectives. The most widely known of these is the list of verbs that accompanies Bloom’s Tax- onomy of Instructional Objectives. Bloom and col- leagues wrote the taxonomy in the late 1950s as a means to organize objective s according to their cogni- tive complexity. The six levels of this taxonomy, ordered from the least complex to the most complex, are to know, comprehend, apply, analyze, synthesize, and evaluate. The lowest level of this taxonomy, to know, refers simply to the memorization and recitation of facts. Evaluation, however, not only requires factual knowledge but also the ability to make judgments about that knowledge. Each level can be translated into instructional objectives by using a set of verbs that cor- responds to each level. The verbs describing knowl- edge and analysis that were listed earlier in this entry are two examples of these verb sets. Other examples include the verbs compose, design,and expand to iden- tify clearly what is meant by synthesis. Compare, con- trast ,and judge are three verbs that can turn evaluate into a clear and unambiguous objective. Complete lists of these verb sets can be found in most references on instructional objectives. In addition to the use of specific verbs, teachers must give consideration to several other factors when writing instructional objectives. For example, instruc- tional objectives must be close in time and reference outcomes that can be both observed and measured. This means that objectives must describe a behavior that the teacher can either see or hear. A teacher can see, for example, students’ written responses or answers to mathematics problems. The teacher can also see the results of students’ science experiments or created representations. Musical performances, such as playing a scale or singing a particular note, provide good opportunities for objectives that are heard. Each of these shares the characteristic of speci- fying a behavior that the student must exhibit in some way to the external world. The ABCDs of Written Objectives Suitably written instructional objectives contain four elements that can be expressed as the ABCDs of objectives. In this system, A stands for audience,B for behavior , C for conditions ,andDfor degree.The audience is the intended group of learners to which the objective applies. The audience may be seventh- grade science students, first-grade readers, or fourth- grade learning disabled students. The benefit of attending to the audience when writing instructional objectives is that, by stating the learners to whom the objective applies, it structures the objective so that it is focused on the learner. Behavior refers to what the learners are to do and is indicated by the verb of the objective. Conditions indicate the exact circumstances under which the behavior is to occur. Conditions clarify the resources that learners will have available at the time of the performance and the circumstances under 534 Instructional Objectives which the behavior must be performed. It is the condi- tion element of the objective that specifies, for exam- ple, if the behavior must be exhibited independently or with the aid of a partner, if students will be permit- ted to use notes or books, or if mathematics problems can be solved with the aid of a calculator. The final element, the degree, identifies the standards for an acceptable performance. It is the degree element of the objective that clarifies the quality or quantity of the behavior necessary to achieve a level that is deemed to be sufficient. Degrees might be expressed as the percentage of problems to be answered correctly, the number of errors that can be made, or the amount of time that a behavior should require. The degree element is most difficult to express when the objectives corre- spond to subjective performances such as writing a good summary or creating a novel design. In these cases, it is important that the objectives are tied to clearly stated scoring criteria. A good summary, for example, may contain the main idea, three supporting details, and a synthesis statement. Sharing these criteria with learn- ers may clarify expectations and further specify the stated objective. Categories of Written Objectives To write instructional objectives, teachers must also consider the type of behavior that is the target of the objective. Objectives can be categorized as psycho- motor, cognitive, or affective. Psychomotor objectives refer to behaviors that the learner is to perform. Play- ing a musical instrument or executing an athletic move is an example of a psychomotor objective. In academic domains, psychomotor objectives can refer to the execution of activities such as properly arran- ging manipulatives, operating equipment, or manag- ing behavior. Cognitive objectives refer to what the students will learn or the intellectual capacity they will acquire through instruction. There are various types of cognitive objectives, such as comprehension or problem solving. Most resources on instructional objectives recommend using the levels of Bloom’s taxonomy to conceptualize cognitive objectives. Cor- responding verbs can, of course, be used when writing these objectives. Finally, instructional objectives can refer to affec- tive outcomes. Affective objectives include students’ attitudes, values, and expectancies. An affective objective may state, for example, that students in a mathematics class will have confidence in their ability to complete mathematics problems or that the students will understand the value of a particular mathematical procedure to their everyday lives. In general, affective objectives are the most difficult to both write and assess because it is difficult to deter- mine the objective and observable behaviors that cor- respond to the desired outcome. The Role of Objectives in Instruction and Assessment Once written, objectives prov ide guidance for the design of instructional materials an d activities. Although there is not a one-to-one correspondence between a written objective and the instructional methods that can be used to achieve the objective, a well-written objec- tive does guide the teacher’s decision-making pro- cess. When selecting instructional materials, for example, the teacher must choose materials that con- tain the necessary information and that present the information in a manner consistent with the objec- tives. In class, instructional activities should also provide opportunities for practice and feedback on the desired behaviors. Scaffolds to support student progress toward the intended outcomes may also be included in the materials. Furthermore, because instru ctional objectives require an observable behavior, they are also used to select the assessments that are used to determine if the objective has been achieved. The in-class activities, take-home assignments, and class tests are all consis- tent with the stated objective so that the perfor- mances for which students are held accountable are the same as those communicated to them through the objective. Student performance on these assessments provides the opportunity for teachers and students alike to assess progress toward the intended out- comes. When final assessments, such as a unit exam, are given, the assessment should align with the objec- tives that preceded it. The conditions of the exam, for example, should be consistent with the conditions of earlier objectives. In short, students should be assessed only on behaviors and abilities that were part of earlier objectives. Theories of Learning and Instruction Several theories of learning and instruction discuss the role of instructional objectives in student learning. Instructional Objectives 535 Contingency contracts are recommended by behav- ioral learning theories as a method for the teacher and student to discuss and establish the goals and con- ditions for learning-related outcomes. Contingency contracts are used with individual students. In these contracts, the instructional objective serves as the statement of the desired terminal behavior. Conditions for the behavior and consequences for the outcome are also included. Gagne recommends that objectives be incorporated into the instructional design process. In this theory, objectives are classified according to one of five cate- gories of learning outcomes (e.g., verbal information, cognitive strategies). Each category corresponds to a set of critical learning conditions, and the conditions specify the environmental conditions the learner needs in order to achieve the goal. By considering the condi- tions of learning alongside the categories of objec- tives, the instructional designer can translate the instructional objective into the instructional design. Peggy N. Van Meter See also Bloom’s Taxonomy of Educational Objectives; Contingency Contracts; Goals; Grading Further Readings Bloom, B. S., Engelhart, M. D., Furst, E. J., Hill, W. H., & Krathwohl, D. R. (1956). Taxonomy of educational objectives: Handbook I, cognitive domain. New York: McKay. Gagne, R. M., Briggs, L. J., & Wager, W. (1992). Principles of instructional design (4th ed.). Fort Worth, TX: Harcourt Brace. Mager, R. F. (1984). Preparing instructional objectives (2nd ed.). Belmont, CA: Lake. I NTELLIGENCE AND I NTELLECTUAL D EVELOPMENT Modern Conceptions of Intelligence The modern history of theory and research on intelli- gence has its twists and turns largely due to the unwieldy nature of the concept. On one hand, intelli- gence is a concept that has high currency, a valued human resource that people try to cultivate or harness for advancing their causes and agendas, individually or collectively. In the meantime, it is also an abstract, elusive concept with many faces. When a task force put together by the American Psychological Associa- tion (APA) reported ‘‘knowns and unknowns’’ about intelligence, it was not able to come up with a uniformly agreed-upon definition of what intelligence is, other than the following statements by Ulrich Neisser: Individuals differ from each other in their 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. Although these indi- vidual differences can be substantial, they are never entirely consistent: A given person’s intellectual performance will vary on different occasions, in different domains, as judged by different criteria. Concepts of ‘‘intelligence’’ are attempts to clarify and organize this complex set of phenomena. (Neisser et al., 1996, p. 77) Three observations can be made about the state- ments. First, there is some consensus in the research community on what are typically seen as constituents of intelligence or intelligent behaviors; however, there is no clear answer as to whether they are closely connected facets or just concepts loosely coupled together. Second, the statements treat intelligence squarely as a differential or individual difference con- cept, yet give much leeway for intraindividual and contextual variability. Finally, the statements high- light the term intelligence as a psychological con- struct, a conceptual tool conjured up by scientists to sort and organize observations at an abstract level, not a physical reality like height or weight. Although Francis Galton started the tradition of research on psychometric intelligence, Alfred Binet and Charles Spearman were the two most prominent early pioneers of modern theory and measurement of intelligence. Binet, in collaboration with his doctoral student Theodore Simon, developed the first modern intelligence test for the purposes of identifying and helping children with severe learning difficulties in school. Although the purposes were to develop a more reliable and objective assessment than informal clini- cal observations could offer, Binet saw the instrument as a clinical tool for diagnostic and instructional pur- poses. He also believed that intelligent performance and behavior involves a set of processes that can be 536 Intelligence and Intellectual Development identified in children’s performance and targeted for intervention. In comparison with Binet, Spearman was a different kind of researcher. He firmly believed that human intelligence can be clearly defined and measured with accuracy. He used simple measures of sensory discrimination as an indicator of intelligence, believing that sensitivity to subtle differences and relations best characterizes intelligent persons. In con- trast to Binet’s inclinations as a clinician, Spearman was a mathematician, who preferred numbers to immediate observations. By parsing performance indi- ces into a shared variance and residue variance, he formulated a two-factor theory: individual differences in intelligence can be represented as consisting of a general factor ( g ) and specific factor ( s ). When Spearman made a bold claim with a title of ‘‘‘General Intelligence’ Objectively Determined and Measured’’ for his famous 1904 article, Binet was not convinced; he doubted whether a phenomenon as complex as intelligence can be reduced to a single number or a set of numbers. Indeed, he made the counterargu- ment that two individuals who obtain the same score might well use quite different skill sets. Binet was more intrigued by subtle individual differences observed during performance than the apparent sim- plicity of the mathematical solution offered by Spear- man. This tension, revealed in exchanges between Spearman and Binet and alluded to in the quoted statements above by the APA task force, has lingered to date. Intelligence: Structural or Functional? Conceptualizing intelligence as a structural feature of mind starts with Galton, who, along with many of his contemporaries, viewed intelligence as a heritable mental faculty. The structural view of intelligence was reinforced by massive intelligence testing and consolidated by the then-newly invented correlation and factor analytical technique. Efforts to delineate psychometric intelligence culminated with J. Paul Guilford’s mapping of various configurations of abili- ties based on content, process, and product, and John Carroll’s reanalysis of hundreds of psychometric stud- ies of human abilities. Although the structural view of intelligence implicitly assumes that intelligence is a capacity of some sort, some voices resist such reifi- cation. Some scholars argued that psychometrically measured intellectual performance is better seen as an index of the effectiveness and efficiency of mind vis-a ` -vis an array of task conditions rather than mental entities. An alternative, functional account involves an understanding of the context in which performance is observed and assessed, as well as how the person carries out the task. Whereas the structural view defines intelligence squarely as a person charac- teristic, a functional view defines intelligence at the interface of an enactive person and an impinging environment, as fit execution of behavior or perfor- mance in that context. In short, when the structural view sees competence as a personal trait, the func- tional view sees competence as context dependent. Intelligence: Nature or Nurture? The early pioneers of intelligence research differed with respect to whether mental capacity is heritable. Whereas Galton firmly believed that intelligence is largely a heritable quality, Binet considered it a human condition that can be modified through education and social interventions. Whether the quality called ‘‘intel- ligence’’ can be improved through education is still controversial today. There is a pervasive pessimistic belief that people cannot do much when it comes to intelligence. Supporting evidence comes from twin studies that show that as one reaches adolescence and adulthood, genetics seems to play an even more sig- nificant role in one’s intellectual performance than when one is younger. On the other hand, evidence also indicates that intelligence is a malleable quality, and schooling and effective instruction make a differ- ence in one’s intellectual performance and cognitive organization of personal experience. Raymond Cattell developed a more differentiated scheme in which fluid intelligence (Gf), the ability to manipulate complex information and detect patterns and relations, is interpreted to have direct biological underpinnings, whereas crystallized intelligence (Gc) reflects the cumulative effect of experience and edu- cation. Thus, Gf represents true genetically based intelligence and Gc is simply a derivative outcome of Gf acting upon experience and knowledge. There is a body of research on cognitive aging that seems to support the notion that Gf tends to decline with aging, but this trend is compensated for by the incremental changes in Gc. However, research also demonstrates that environment (likely including education) pro- duces greater effects on Gf than Gc, affirming an opposite contention that fluid abilities are among the most important products of education and experience. Intelligence and Intellectual Development 537 Indeed, an important task not fulfilled by the tradi- tional IQ tests is how to design instructionally rele- vant useful tests of fluid abilities, showing how well students can transfer their learning to novel problems. However, when one examines what carries the most weight in general intelligence and in predicting future performance, crystallized intelligence seems to be a winner. Thus, the contention that Gf represents ‘‘natural ability’’ and Gc is simply ‘‘achieved compe- tence’’ is a controversial one. The nature-nurture issue is also related to whether one views intelligence as ultimately a structural fea- ture of the person, reflecting a capacity, or a relational and functional property, reflecting the person–task interaction. At least three major sources of intelli- gence can be identified: biological, domain experi- ence, and reflective. Biologically based intelligence (e.g., neural efficiency) may be difficult to modify, but both domain experience and reflective thinking are subject to significant environmental influences. Intelligence: General or Specific? At face value, standard intelligence tests are a com- posite measure of performance on a variety of tasks, originally intended to be th iswaybyBinet.Thepracti- cal utility of such a test may lie in the very fact that it is a gross measurement, like the Dow Jones Index, sam- pling as many ‘‘active performers’’ as possible to obtain an overall estimate. The paradox is that the broader the range of tasks a test covers , the less psychologically meaningful the test becomes. The trade-off seems to be between specification of cognitive (and possibly motivational) proc esses given a cognitive task, and the breadth of representations of task conditions that affords performance consis tency, stability over time, and predictive validity. Practicality aside, it becomes theoretically problematic when one attempts to interpret various factor structures as indicative of how the mind is structured. Spearman, for one, ventured into such a speculation when he interpreted the general factor as ‘‘mental energy.’’ The three-stratum theory proposed by Carroll in 1993 represents an integration whereby cog- nitive abilities are represented as a continuum from the most general to the most specific. Yet many researchers questioned whether the factor structures can truly afford a theory of the structure of human abilities, or they just reflect a statistical artifact. Nevertheless, there is still a strong belief among many students of intelligence that general intelligence exists and that standard intelligence (IQ) tests mea- sure it well. When it comes to understanding the nature of general intelligence, some take a more reductionistic view by tracking it down to its neurobi- ological roots. Recent research of developmental biol- ogy also seems to suggest that prolonged thickening of cortices may underlie more advanced cognitive development of individuals whose IQ scores place them roughly at the top 3 % of the population. Others characterize general intelligence as the ability to deal with cognitive complexity; that is, more complex tasks require more mental manipulations of informa- tion, hence higher demands on mental capacity. Intelli- gence tests have been found to be correlated with high- complexity tasks more than low-complexity tasks, although exceptions also exist. Research on mental retardation also suggests deficits in extracting abstract relations and principles. Although psychometricians have tried to map out human abilities, general or specific, for a long time, Howard Gardner and Robert Sternberg brought to the field different breeds of theoretical perspectives and research evidence. Gardner views psychometrically measured IQ as representing a culturally narrow view of what is important for effective intellectual func- tioning. His theory of multiple intelligences, for good or ill, has successfully pluralized the concept of intel- ligence. Moreover, his argument that the mind is not an all-purpose information-processing device but is composed of many specialized modules dedicated to processing specific types of information was based on a set of neuropsychological evidence. The underlying argument that processes are always sensitive to content is now widely supported. In comparison, Sternberg’s triarchic theory represents a more complex system of theoretical propositions, encompassing cognitive, experiential, and contextual dimensions. The question of whether intelligence is unitary and general or pluralistic and dom ain-specific often carries a structuralist overtone concerning how the mind is innately structured and organized, regardless of envi- ronmental experiences. It does not take into account the possibility that mental capacities can also be shaped by task environments over time. Gardner expressed a structural view of intelligence when he conceptual- ized the mind as innately modular. His recent concep- tions seem to move toward a more functional view. A functional view of intelligence is by nature more domain-specific and context-bound. It does not presume, however, that the mind is innately domain-specific. 538 Intelligence and Intellectual Development Rather, domain-specific competence could be the prod- uct of adaptive efforts that might involve both domain- general and domain-relevant resources. Early Conceptions of Intellectual Development From the onset, developmental approaches to intelli- gence take a different approach from differential or individual difference approaches, assuming that it is a function of age-graded development; that is, sooner or later a person will go through similar developmen- tal changes in his or her intellectual structures and functions. Although working in Simon’s laboratory on child psychology, Jean Piaget saw something that was apparently missed by psychologists of his time; that is, children’s thinking has their own ‘‘logic’’ that is dif- ferent from adults’. Piaget envisioned a developmental process that is completely outside the radar of differen- tial psychology: At different developmental levels, intelligence has its different structures and functions, showing different organizational principles in cognitive functions. Such a developmental orientation has turned out to be extremely fruitful in understanding how chil- dren act on and represent their world, and how educa- tors can facilitate children’s intellectual development. Oddly enough, although Piaget differed significantly from differential psychologists in his theoretical inter- ests, his assumption about the existence of deep struc- tures of intellect (schemes and operations) reflects a conviction similar to that of differential psychology; that is, mapping the structure of intellect is possible just as is mapping the physical structures of an organism. However, Piaget also started off a tradition of devel- opmental research that shows little interest in individ- ual differences. The separate paths of developmental and differential psycholog y have yielded findings and theories that are virtually noncommunicative with each other. On one hand, developmental researchers are seeking an understanding of how an ‘‘average’’ child develops intellectually or cognitively over time, while regarding individual differe nces as trivial or ‘‘noises’’ to be dismissed. On the other hand, consistent differ- ences in intellectual perfo rmance observed within any age have prompted differential psychologists to develop age norms for individual differences in academic and intellectual performance calibrated to months of age. Because IQ scores are age-normed, intellectual develop- ment from such a different ial point of view is simply how stable these age-normed individual differences are over time. Both traditions can be criticized as missing an important part of intellectual development. On the differential side, age-normed rank order scores mask incremental changes in intellectual functioning and qual- itative changes or reorganization of cognitive functions. Indeed, age-normed standard scores help perpetuate the notion that intelligence is a fixed quality, and by a further leap of faith, a genetically ba sed individual difference. On the normative developmental side, in seeking to understand a typical or ‘‘average’’ child at a given age, the normative developmental psychology is also guilty of neglecting vast individual differences in intellectual functioning and development, not only in terms of psy- chometrically measured indi vidual differences, but also in terms of different pathways and trajectories. Metatheoretical Assumptions Guiding Theory Building There are three main metatheoretical frameworks guiding research and theorizing: mechanistic, organis- mic, and contextualist. Mechanistic perspectives would simply see intellectual development as a deriva- tive outcome of changes in cognitive machinery (e.g., working memory capacity). Organismic per- spectives would view intellectual development as reg- ulated by internal rules of growth (e.g., disequilibrium or innate skeletal principles). Contextual perspectives would view intellectual development as fundamen- tally embedded in the broader sociocultural context and situated at the interface of person–environment interactions (e.g., zone of proximal development). Whether development of intelligence should be considered differential, quantitatively or qualitatively, is a matter of whether the core ontological commitments endorse a differential provision. Mechanistic approaches can lead to theories of differential intellectual develop- ment, in reading or other cognitive development, as long as the development is traced to the basic cognitive struc- tures and operations. Organismic principles can also yield insights into differential development of intellec- tual competence by specifying when individuals diverge in how they negotiate the max imizing of mastery of the environment on one hand, and the optimizing of one’s affect on the other. The contextualist doctrine, by far, offers the most unconstrain ed versions of intellectual development. On one hand, it is liberating by permitting various environmental forces (including fortuitous events and life-changing encounters) and individuality (with all its idiosyncrasies) to play a role in intellectual Intelligence and Intellectual Development 539 development. On the other hand, it opens up a multitude of developmental possibili ties that may prove unwieldy for scientific research or ma yfallshortofparsimony. Again, there is a tension on the nomothetic or universal versus ideographic or parti cularistic continuum where cognitive and intellectual development are concerned. Notwithstanding the challenges of integrating differential and developmental theories and research in a theoretically coherent manner, developmental approaches stand the best chance to address the three basic questions regarding intelligence discussed earlier. Traditional intelligence testing, and its meth- odological backbone, factor analysis, represent a static method and therefore cannot afford insights into dynamic person–environment interactions and changes of intellectual functions over time. By studying the tem- poral sequences of person–t ask or person–environment transactions, the structural-functional tension can be addressed as an issue of how initial structure facilitates functionality and how functionality leads to new struc- tures. By studying nature and nurture in reciprocation and interaction, how biological preparedness and envi- ronmental affordances and constraints work in concert as a system can be further explicated (e.g., passive, evocative, and active correlations between the person and the environment). By studying intellect in the making, it is possible to show contributions of both domain-specific and domain-ge neral cognitive resources. Because individual differences in intellectual develop- ment are one of the most important educational consid- erations, it is imperative from an educational point of view to incorporate a differen tial provision of how indivi- duals differ in their intell ectual development, and how learning and instructional act ivities enhance intellectual functioning and development. New developments in the fields of developmental and differential psychology show good promise of such a theoretical integration and consilience. New Developments on Intellectual Functioning and Development There are five aspects of current thinking that facili- tate an integrative approach to intellectual functioning and development: 1. The importance of functional and social contexts, 2. The reciprocal relationship between functioning (including learning) and development, 3. The role of nonintellective factors in intellectual functioning and development, 4. A life span perspective on intellectual development, and 5. Developmental processes and mechanisms leading to differential intellectual development. The Role of Functional and Social Contexts In a narrow sense of the term, context refers to a set of immediate conditions where specific intellec- tual performance is observed. It can include the nature of tasks involved, situations in which the performers find themselves, and instruments and criteria used to make observations and assessment as well as tem- poral changes of strategies and performance. This emphasis shifts from an exclusive focus on intellectual performance as a person variable (i.e., competence) to a focus on intellectual performance as relational property of person–task interaction in real time (i.e., perfor- mance). Microgenetic methods, which follow indivi- duals’ interactions with a specific task environment intensively for days and weeks, uncover intraindividual as well as interindividual variability in children’s intel- lectual performance. Such an idiographic approach to studying real-time, micro-level developmental pro- cesses has significantly changed the way development is understood, from a view of monotonic incremental or structural changes to that of variation, selection, and optimization, not unlike the process of biological evo- lution. Such a micro-level process view of development integrates functioning and development. At a more abstract level, context can mean differ- ent functional contexts where intelligent behavior may entail different sets of capabilities and propensi- ties, such as academic versus practical settings. Thus, Brazilian children can perform well on ‘‘street math’’ but cannot do as well on equivalent ‘‘school math.’’ Professional racetrack gamblers are capable of sophis- ticated reasoning in their domain of expertise but do not perform superbly on standard intelligence tests. Each domain or field may have different sets of abilities and propensities and differen t threshold requirements. Even within academics, requirements for successful adaptations may be quite different. An emphasis on context also implies a specific social milieu or cultural context where intellectual f unctioning and development take place. Lev Vygotsky insis ted that all higher mental functions initially occur at the social level and then 540 Intelligence and Intellectual Development are gradually internalized with practice. The role of more competent others is indispensable. The notion of zone of proximal development treats intellec- tual development as fundamentally mediated by socializing agents. The new movement on ‘‘situated cognition’’ also stresses the distributed nature of intellectual functioning. The Relationship Between Functioning and Development Current thinking and research involve a new under- standing of relationships between functioning and development, and learning and development. Develop- ment is traditionally conside red structural organization and reorganization of experience and cognitive and behavioral functions that evolve over time. Experi- ence and knowledge facilitate this process but do not change its nature. Learning, on the other hand, is seen as a process of the acquisition of new knowl- edge and skills that has little bearing on the cognitive infrastructure. This view has been changed signifi- cantly. Research shows, for example, that children who are chess players performed meaningful chess memory tasks at a much higher level than adults who had not learned chess. The study demonstrates that knowledge significantly alters basic cognitive functioning. The emergent expertise literature pro- vides compelling evidence that knowledge enables sophisticated reasoning and problem solving. Now, learning is seen an integral part of development. Integrating learning and knowledge into develop- mental theory entails a more functional, rather than structural, view of intellectual development; in other words, intellectual development is likely more con- textual than organismic. It opens a new way of looking at intellectual development that stresses the importance of contextual experiences (including educational experience) and the facilitative role of others while incorporating internal principles gov- erning the behavior of the organism at a specific developmental level. Urie Bronfenbrenner and Stephen Ceci argued that biological potential for learning and intellectual devel- opment can be realized only through proximal pro- cesses, that is, transactional experiences with specific environmental contexts both immediate and mediated. Accordingly, learning potential in a given situation, which is typically considered an important aspect of intelligence, can be built into a differential theory of intellectual development. This is in keeping with Vygotsky’s notion of zone of proximal development and its practical application, dynamic testing, which is not assessing what the person already knows, but how well the person learns in real time when given instruc- tional hints and prompts. Dynamic testing helps diag- nose a child’s ability to learn at a specific level of competence, and it informs educational interventions aimed at assisting children with learning difficulties, reminiscent of what Binet was doing during the incep- tion of intelligence theory and measurement. The Role of Nonintellective Factors Both psychometric theorie s of intelligence and age- graded normative theories of intellectual development tend to be ability-centric theories; that is, the kind of abilities a person can display in a perform-on-demand condition. Such ability-centric approaches elicit maxi- mal performance at the expense of neglecting a per- son’s typical engagement, which has much to do with personal dispositions, such as openness to experience. Kurt Fischer made a related d istinction in developmen- tal theory between functiona l-level and optimal-level development, an important revision of Piaget’s theory, which assumes by default an optimal-level develop- ment (e.g., emphasizing what adolescents potentially can do, rather than what they are actually able to do). Nonintellective factors m ay play what Bronfenbren- ner called a development-instigative role. Intellectual dispositions, such as risk-taking and open-mindedness, also play an important role in how one approaches an intellectual challenge. Intel lectual dispositions may lie in the intersection of personality and intelligence. It may be argued that nonintellective factors such as interest and persistence may be particularly important in differential intellectual development, as much knowledge and skill building entails sustained engage- ment and deliberate practice. Personal agency in intellectual development can also take a more conscious form. Development is now seen as a self-modifying process, part of intellectual development as self-engende red changes. All of these conceptions involve a distinct role of the consciousness and self. One example is what Annette Karmiloff- Smith called representational redescription made by children to articulate otherwise implicit knowledge. Rather than seeing intellec tual development as funda- mentally cognitive reorganization due to changes in cog- nitive infrastructure or architecture, Karmiloff-Smith Intelligence and Intellectual Development 541 sees the role of consciousness as reflecting a developing human tendency to exercise cognitive and metacognitive control over aspects of their environment. This is in line with a renewed emphasis on reflective thinking, which was stressed decades ago by Dewey as quintes- sential for effective intellectual functioning. Education seems to play an important role to enculturate such habits of mind. A Life Span Perspective Current thinking goes beyond adolescence to embrace a life span perspective on intellectual func- tioning and development. Biologically, the Gc and Gf distinction provides a useful perspective on when one reaches cognitive maturity and when cognitive or neu- ral efficiency starts to decline with the aging process. However, intellectual development is constrained, but not dictated, by biological differences and changes; in other words, intellectual development is not as canalized as other aspects of development, such as language development. This point becomes clearer when one views intellectual development (Gf or Gc) as often enabled by learning experiences and educa- tion. It can also be argued that much of intellectual development occurs beyond adolescence. There is a growing body of research on adults’ differential intellectual development. The findings of behavioral genetics research that identical twins are more alike when they reach and go beyond adolescence, and that nonshared environmental factors play a more distinct role in later development, can be incorporated and further tested in such research. The topic of intellec- tual functioning and development also overlaps with expert performance and development of expertise. Coherent Accounts of Processes and Mechanisms Attempts at integrating differential and develop- mental approaches have been made at the level of childhood, adolescence, and adulthood. However, an important task is to provide processes and mechan- isms that account for differential development in a coherent manner. Some scholars suggest that mental development in the first 6 years is similar for every- one and then diverges due to both environmental and genetic forces. Others provide motivational principles explaining differential pathways and trajectories. Robert Siegler’s overlapping-wave theory of cognitive development also potentially explains how differen- tial development occurs. Studies that incorporate both comparative and microgenetic methods may ulti- mately be capable of addressing the two central issues of intellectual functioning and development: a process account of development that entails the role of adap- tive functioning, and a developmental theory that is capable of addressing differential pathways and tra- jectories. In this way, differences between nomothetic and idiographic approaches to understanding intelli- gence and intellectual development can be eventually resolved or reconciled. David Yun Dai See also Bell Curve; Emotional Intelligence; Fluid Intelligence; Gifted and Talented Students; Metacognition and Learning; Multiple Intelligences; Triarchic Theory of Intelligence; Vygotsky’s Cultural-Historical Theory of Development Further Readings Carroll, J. B. (1993). Human cognitive abilities: A survey of factor-analytic studies. Cambridge, UK: Cambridge University Press. Ceci, S. J. (1996). On intelligence: A bio-ecological treatise on intellectual development (2nd ed.). Cambridge, MA: Harvard University Press. Ericsson, K. A., Charness, N., Feltovich, P. J., & Hoffman, R. R. (Eds.). (2006). The Cambridge handbook of expertise and expert performance. New York: Cambridge University Press. Gardner, H. (2003). Three distinct meanings of intelligence. In R. J. Sternberg, J. Lautrey, & T. I. Lubert (Eds.), Models of intelligence: International perspectives (pp. 43–54). Washington, DC: American Psychological Association. Guilford, J. P. (1967). The nature of human intelligence. New York: McGraw-Hill. Lohman, D. F., & Rocklin, T. (1995). Current and recurrent issues in the assessment of intelligence and personality. In D. H. Saklofske & M. Zeidner (Eds.), International handbook of personality and intelligence (pp. 447–474). New York: Plenum. Messick, S. (1992). Multiple intelligences or multilevel intelligence? Selective emphasis on distinctive properties of hierarchy: On Gardner’s Frames of Mind and Sternberg’s Beyond IQ in the context of theory and research on the structure of human abilities. Psychological Inquiry , 3 , 365–384. Neisser, U., Boodoo, G., Bouchard, T. J., Boykin, A. W., Brody, N., Ceci, S. J., et al. (1996). Intelligence: Knowns and unknowns. American Psychologist , 51 , 77–101. 542 Intelligence and Intellectual Development Perkins, D., & Ritchhart, R. (2004). When is good thinking? In D. Y. Dai & R. J. Sternberg (Eds.), Motivation, emotion, and cognition: Integrative perspectives on intellectual functioning and development (pp. 351–384). Mahwah, NJ: Lawrence Erlbaum. Sternberg, R. J. (Ed.). (2000). Handbook of intelligence. Cambridge, UK: Cambridge University Press. I NTELLIGENCE Q UOTIENT (IQ) Intelligence is a construct that has been proposed by psychologists to underlie much of human behavior and is a significant factor contributing to an individ- ual’s ability to do some things more or less well. Most would agree that some children are better at math or language arts than others, or that some hockey players or musicians are gifted in compari- son to their peers. It might be argued that some indi- viduals are born that way, whereas others have the benefit of good environments and learning opportu- nities that can build on their basic abilities. The intelligence test, and resulting intelligence quotient or IQ, is a means for assessing and measuring intel- ligence, with the results often used to classify or select persons or predict such outcomes as school achievement. Both the construct of intelligence and its measure- ment are not new, and both existed well before the advent of psychological science. Historians have traced the forerunner of current cognitive ability and achievement assessment to more than 2000 years B . C . Although intelligence has been studied in a number of ways, from an early emphasis on sensory processes to the more current attention given to brain-imaging techniques, the mainstay in the study and assessment of intelligence has been the IQ test. Psychologists not only assess intelligence but also study how intelli- gence is expressed; what causes it; and how it contri- butes to understanding, explaining, predicting, and even changing human behavior. Despite intelligence being a much studied area of psychology, there is still considerable controversy and emotion regarding the use of the IQ and intelligence tests and the results gleaned from them in such contexts as schools and industry to describe both individuals and groups. Given continued advances in the theories of intelligence and cognitive assessment instruments, the issue appears to be less with the con- structs and the tests used to measure it, and more with how this information is or can be used. Theories of Intelligence Psychology joined the scientific community in the late 1800s, and since then, a number of theories outlining human intelligence, accompanied by a huge body of research, have emerged. The hallmark of science and scientific inquiry is the creation of theories and the pursuit of empirical support for the hypotheses that are generated by and from a particular theory. The current theories of intelligence attempt to explain what it is, what causes it, and what intelligence tells us about other human behaviors. Although research has demonstrated that there is a considerable genetic component to intelligence, it is also recognized that intelligence is an acquired ability that reflects opportunity and experience such as comes from effective schooling and home environ- ments. Studies showing the remarkable similarity in measured ability between twins, whether reared together or apart, provide much evidence for a genetic foundation to intelligence. However, intelligence appears to be polygenic rather than located on a spe- cific gene. Studies have also shown that animals raised in very restricted in contrast to ‘‘rich’’ environ- ments not only show considerable differences in, say, their capacity to solve problems, but also show an impact on their brain structures (e.g., number of neural connections). As well, research has shown how the effects of poverty and restricted educational opportunities can negatively influence human devel- opment, including intelligence. Among the environmental factors that are known to directly influence brain functioning and thus intellectual development and expression are various medical conditions, neurotoxins, drugs such as alco- hol (certainly during pregnancy, as observed in chil- dren diagnosed with fetal alcohol syndrome), and chemical pollutants such as lead and mercury. Almost anything that negatively affects the brain, such as head injury and oxygen deprivation, will have small or large observed effects on intelligence and its expression. Less obvious but just as impor- tant are such additional factors as motivation, self- concept, and anxiety, all of which can influence a person’s score on an IQ or intelligence test and their everyday functioning at work or school. Intelligence Quotient (IQ) 543 Culture also affects the expression of intelligence. Although there is a universal ability related to the capacity to acquire, store, retrieve, and use information from everyday experiences as well as from direct teaching (e.g., school), how this is expressed, the con- tent of a person’s response to a question, and the lan- guage used in providing an answer to a question all reflect the interaction between the person’s genetic capacities and the environmental opportunities for intelligence. In addition, arguments have been made that what constitutes intelligence may vary across cul- tures and that different ethnic groups may have differ- ing, but equally intelligent, reasoning strategies. On the other hand, the successful ad aptation of contemporary assessment instruments for use in a large number of countries suggests that centr al abilities and capacities comprising intelligence ma ybesharedacrosscultures. It should also be pointed out that intelligence is also a developmental construc t. A 5-year-old child has a very different view of, say, cause–effect relationships or the understanding of number concepts than does a 15-year-old in Grade 10 or a 35-year-old with a uni- versity degree or a 50-year-old working in a factory. Brainmaturationverymuchinfluencesthequalitative description of intelligence. At the same time, it has been demonstrated that inte lligence does change across the life span, with some kinds of intelligence referred to as crystallized intelligence (e.g., a person’s knowl- edge of words and language, learned skills such as solving arithmetic problems) more likely to remain unaffected and possibly continue to improve with age than are abilities reflecting fluid intelligence and speed of processing information (reflecting neural efficiency), barring, of course, dementia and other diseases under- lying cognitive decline. Another debate found in theoretical discussions and observed in models of intelligence is centered on whether intelligence is a single characteristic or is composed of several or even multiple abilities. These views can be traced back to the turn of the previous century, when psychologists such as Spearman argued that intelligence was a set of specific but related fac- tors that resulted in an overarching general factor (essentially similar to the current full-scale IQ [FSIQ] score found on many tests). In contrast, Thurstone proposed that intelligence was made up of a number of primary mental abilities that could not be captured in a single summary score or an FSIQ. Today’s tests and models continue to reflect these divergent viewpoints. For example, psychologists such as Guilford have proposed that intelligence may have 120 or more facets, while Wechsler has argued for the relevance of the FSIQ (but also the importance of look- ing at both verbal and nonverbal performance). Other current models proposed by St ernberg, describe intelli- gence along the lines of practical, analytical, and crea- tive abilities, whereas Gardner suggests that there are likely eight to nine core kinds of intelligence reflecting, for example, interpersonal intelligence (required for effective social interaction and communication), kines- thetic intelligence (obser ved in athletes who excel in their sport), musical ability (found in performers and composers), and logical-m athematical i ntelligence (reflectingthecapacitytoreasonlogicallyinmathe- matics and science such as physics). Other views, drawing from the work of Piaget, focus more on how intelligence develops (in stages) and how it can be encouraged through direct in struction and supportive learning environments (e.g., instrumental enrichment). Thus, there is quite some diversity in how intelli- gence is defined, determining the key factors that affect its development and expression, and how it is best measured. Although this may be perplexing to some, it does show how complex intelligence is and, even more so, how very complex human behavior is. At the same time, a great deal is known about intelligence and what it tells us about human behavior. For example, intelligence tests, yielding a measure of general men- tal ability, are one of the best predictors of student achievement and success in elementary schools. On the other hand, and as expected, intelligence tests have been found to be more limited in predicting achieve- ment among intellectually h omogeneous populations. For example, university s tudents generally possess average or above-average levels of intelligence such that divergent performance in this group appears to be more highly related to specific cognitive competencies (e.g., high aptitude in math ) and personal attributes (e.g., motivation, study skills). Intelligence is addition- ally considered a key factor in understanding human capacity to manage stress and develop resiliency, psy- chological well-being, and even longevity. History of Intelligence Testing The very earliest tests of intelligence were not based on any particular scientific views and in many instances simply showed the wide or narrow range of perfor- mance on such tasks as strength of grip or pitch dis- crimination. More to the point, these tests did not tell us 544 Intelligence Quotient (IQ) about other human characteris tics that, by expectation, they should. If intelligence is an underlying capacity that influences how well a person does in school, or a person’s accuracy at solving arithmetic problems, or the speed at which he or she can perform other mental tasks, then the tests should be correlated with those behaviors and be able to predict how well a person may perform on those tasks requiring intelligence. In contrast to the earliest tests of intelligence, more recent intelligence tests ha ve resulted from extensive research efforts, while still garnering a great deal of misunderstanding from the general public. The first suc- cessful intelligence tests were developed by Binet and Simonattheturnofthelastcenturyandusedinthe schools of Paris, France, to help identify and classify schoolchildren according to t heir ability to learn and whether they would benefit from regular or special school programs. A short time later, these tests were introduced in the United States. Along with the Army Alpha and Beta intelligence te stsusedtoscreenmilitary recruits during World War I, there was growing opinion that intelligence tests had considerable value for pur- poses ranging from personnel selection to identifying children who were intellectually gifted or retarded. These early landmarks in the history of testing laid the foundation for the advancement and proliferation of subsequent intelligence tests. For example, the first intelligence test created by Wechsler, in 1939, has evolved into several recent ly published tests for asses- sing intelligence from pres chool years to age 89, and these tests have now been adapted for use in a large number of countries. The number of tests available to psychologists for assessing cognitive abilities has grown considerably over the past 60 to 70 years. Current Intelligence Tests Today’s intelligence tests vary from very brief mea- sures that assess only a limited or narrow part of the broader intelligence framework (e.g., Raven’s Matri- ces) to large comprehensive batteries that tap many dif- ferent aspects of intelli gence ranging from verbal comprehension and spatial reasoning ability to memory and processing speed (e.g., Woodcock-Johnson Cogni- tive). The large number of tests available also includes tests specific to various age ranges, both group and individually administered tests, brief and comprehen- sive batteries, and modified tests for use with, for example, hearing-impaired clients, or clients who are nonverbal or who are less proficient in English. The majority of intelligence tests require a well- trained psychologist administering subtests that require the client to complete a range of tasks. Two broad types of tasks are used on intelligence tests—verbal and nonverbal. Verbal tasks generally entail a verbally presented prompt or question and require an oral response such as defining words (What is a hammer?), responding to general information questions (What is the distance between the earth and the moon?), or iden- tifying similarities between two words (How are con- vention and meeting alike?). Nonverbal tasks usually involve visual stimuli or materials and/or require a psy- chomotor response such as copying geometric patterns using blocks, identifying important parts that are miss- ing from both common and uncommon objects, or identifying patterns within a visual array. Although instructions and prompts to nonverbal tasks are some- times given orally, verbal r equirements are minimized within some tests through the use of gestures, model- ing, or pictorial directions. Both verbal and nonverbal tasks can be employed to measure a wide range of cognitive abilities and capabilities. For example, short-term memory may be assessed through a task requiring a student to repeat a string of presented numbers (verbal task) or to touch blocks in a previously observed order (nonverbal task). Regardless of the types of questions used, the psychologist is careful to ensure that administration and nonintellective factors do not confound the infor- mation gleaned from these tests. For example, it is necessary to make accommodations for persons with, for example, visual, auditory, or motor problems, lest these interfere with their performance on tests that should be specifically tapping intelligence. The raw scores obtained on intelligence tests are given meaning by comparing them to the performance of large and appropriate reference groups. These group performance indicators, called norms , are based on extensive standardization studies whereby the test is administered to large numbers of examinees to both ensure that the test is working well and to build a com- parison group that is similar on key characteristics such as age and that reflects the composition of the larger community (ethnicity, sex, socioeconomic sta- tus, etc.). An individual’s raw scores on the parts and the whole test are then converted to standard scores through the use of tables; these standard scores are often referred to as IQ scores, and in the case of, say, the Wechsler Intelligence Scale for Children–Fourth Edition (WISC-IV), four index scores assessing verbal Intelligence Quotient (IQ) 545 comprehension, perceptual reasoning, working mem- ory, and processing speed, together with a full-scale IQ, are reported with the average score set at 100. Furthermore, based on the use of normal curve pro- portions, scores of 130 would represent intellectually gifted persons; this score is obtained by less than 2 % of the population. Scores of 115 suggest high average ability that exceeds the scores obtained by about 84 % of the population. In contrast, scores of 85 are seen as low average; a person with this score would have scored higher than 16 % of the population, but some 84 % of the population scored higher than him or her. For an intelligence test to be truly useful, it must demonstrate sound psychometric properties that include reliability and validity. Fo r a test to be reliable, it should have a minimum of measurement error, thereby measuring with consistency and precision. Thus, a FSIQ score will have some error associated with it and should never been taken as an exact measure but rather one that reflects a range wherein the person’s true score is likely to be. Validity means that the test in fact measures what it is intended to measure. If the test is supposed to measure acqui red knowledge or crystal- lized intelligence, then it should do just that and not do something else. Although it can be said that current intelligence tests are among the very best measures used by psychologists, certa in caveats still apply. For example, no one test tells everything about a person’s full intellectual ability, because other factors, such as depression, low motivation, test anxiety, or cultural factors, can influence intelligence test scores. Current Uses of Intelligence Tests The use of IQ and other intelligence tests is a complex process that requires a comprehensive understanding and training in such areas as test principles (reliabil- ity, validity, test construction, norm groups, types of scores); human development; and test administration and interpretation. As such, certain state and provin- cial restrictions exist that limit who is permitted to administer and interpret the r esults. In general, the use of intelligence tests is limited to psychologists or other such individuals who have a minimum of graduate- level training in psychology and assessment. Although most commonly used by school or clinical psychologists within school a nd clinical settings, intel- ligence tests may also be used by psychologists within other specializations (e.g., counseling, industrial organi- zation, research) and in such additional settings as community and state agencies, workplaces, universi- ties, and private practices. In part, the purpose for administering an intelli gence test may vary to some extent depending on the reason for referral and who is administering it and in which setting. A school psy- chologist may use the results of an intelligence test to help decide which students should be selected for a gifted program, whereas a neuropsychologist may use the results to assist wit h determining the location and extent of a brain injury. In general, intelligence tests provide information that can inform a wide range of diagnostic and decision-making processes. Among the most common uses of in