Hockenbury Discovering Psychology 5th txtbk

302 CHAPTER 7 Thinking, Language, and IntelligenceIN FOCUSNeurodiversity: Beyond IQCan intelligence be summarized by an IQ score? Do standard intelligencetests adequately measure intelligence? Although thequestions seem very abstract, their answers can have very realconsequences. To give these questions a human face, considerthe case of people with autistic symptoms.Tom, whose story you read in the Prologue, has a very high IQas measured on standard intelligence tests. However, his inabilityto navigate social situations makes him less competent inmany everyday activities than people with lower IQ scores.Such difficulties are the hallmark of the autism spectrum disorders,whose common feature is problems with communicationand social interaction. Autism is the most severe of these disorders.Along with severely impaired communication, autistic individualsmay be unresponsive to social interaction, engage inrepetitive or odd motor behaviors, and have highly restrictedroutines and interests (Toth & King, 2008).Unlike children with autism, children with Asperger’ssyndrome show normal, even advanced, language development.They may exhibit unusually narrow interests and inflexiblebehavior, but to a much lesser degree than people withautism. And by definition, people with Asperger’s have an IQin the normal to genius range.What about the cognitive abilities of people with autism?Many people believe that most autistics are autistic savants, likethe character “Raymond” played by Dustin Hoffman in the movieRainman. Autistic savants have some extraordinary talent or ability,usually in a very limited area such as math, music, or art. In reality,Percentile100908070605040302010026%56%AutisticWISC-III global scoreSource: Dawson & others (2007).Non-autisticcontrolDifference isnot statisticallysignificant70% 72% Raven’s matrices scoreMeasuring Intelligence On the average, autistic children scoredfully 30 percentile points higher on the nonverbal Raven’s ProgressiveMatrices Test than they did on the WISC-III, whichdepends heavily on oral instruction and responses. In contrast, amatched control group of non-autistic children received scoresthat were essentially identical. Adult participants showed a similarpattern. Although a small-scale study, such results suggest thattraditional intelligence tests may underestimate intelligence inautistic children and adults. In fact, one-third of the autistic childrenscored above the 90th percentile on the Raven’s, but nonedid so on the WISC-III. One child raised his score 70 percentilepoints from 24 to 94 percent—putting him in the “highly intelligent”range rather than the “low-functioning” range.Sample Items from the Raven’s Progressive Matrices TestThe Raven’s test consists of matrix problems that becomeprogressively more difficult. The instructions are simple:Choose the item that best completes the pattern. The testwas developed to test general mental ability and is thoughtto be the “purest” measure of Charles Spearman’s g factor(Holyoak, 2005).only about 1 in 10 autistic people are savants (see Dawson &others, 2008; Treffert & Wallace, 2003). However, fewer than 1 in2,000 non-autistic people have such exceptional abilities.Another common assumption is that most people with autismare mentally retarded (e.g., Brown & others, 2008). Mentalretardation is a condition in which IQ is 70 or below. However,surveying decades of research, psychologist Meredyth Edelson(2006) found that there was little empirical research to supportthe claim that the majority of autistic people are mentallyretarded. In fact, because their symptoms vary so much, it’s verydifficult to generalize about the cognitive abilities of people withautistic spectrum disorders (Sigman & others, 2006).It is also hard to accurately measure intelligence in people wholack the ability to communicate or who are not good at socialinteraction. In children, for example, intelligence is most commonlymeasured by Wechsler-based tests, like the WISC-III. Butis the WISC-III, which relies heavily on verbal instruction and oral