Bayley Scales Part 1: Infants Assessed, but Adults, Too?

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The Bayley Scales of Infant and Toddler Development III (BSD III) are an important tool for measuring the cognitive, motor, and sensory development of the very young. But why is there a need to test infants and small children? We may even recoil from this process, thinking that early testing and assessment may imprint a self-fulfilling prophecy, usually a negative one. Some even wonder if it might be cruel to require a child to perform tasks required by standardized testing. And how are test results to be explained to parents and caregivers?

Because the number of children with special needs continues to increase, and because early intervention not only helps spur development as well as being cost-effective, psychological testing of infants and toddlers is needed in order to decide who is eligible to benefit from these expensive services. Both Public Law 94-142 and the Individuals with Disabilities Act PL 105-17 (IDEA) provide definitions and mandates of who is eligible to receive services. Experts agree that early identification and intervention will result in the remediation of some of the disabilities of these young children and may, in turn, result in a decreased need for later services.

Many experts in psychological testing consider the BSD III to be the finest example of a psychological test ever created. The original version, developed by Nancy Bayley, was published in 1969 and was geared to assess developmental delays in children ages 2 to 30 months old. Harcourt Assessment, publishers of the test, note that its primary value is “in diagnosing developmental delay or planning intervention strategies.” The test may be used to help qualify a child for special services, demonstrate the effectiveness of those services, serve as a research tool, and even be a tangible guide for parents in understanding child development.

When I display this test to my students in the graduate testing courses at Marist College, they are fascinated. The entire test kit,packaged in a large blue nylon suitcase, weighs between 20 and 30 pounds and includes items such as toy cars, dolls, pegboards, puzzles, picture cards, and even a purple rhinoceros that squeaks when it is grasped. There is even a large mirror that always elicits a smile when placed in front of a student. Perhaps some of the intuitive appeal of this test resides in our common experience of having once been very young. However, it is difficult to administer and the test publishers recommend that even psychologists who are experienced with other tests take special training to master the Bayley.

There are three scales that comprise the BSD III. The Mental Scale assesses memory, habituation, problem solving, early number concepts, generalization, classification, vocalizations, language and social skills. The Motor Scale evaluates fine- and gross-motor skills. The Behavior Rating Scale assesses attention, emotional control, and engagement in tasks. The labels used to report scores on the BSD II differ from other cognitive tests. Rather than terms such as “superior” or “average” or “borderline,” classifications include words such as “accelerated,” “normal,” or “delayed.” To further add to the utility of infant and toddler assessment, Harcourt Assessment also offers a 10-minute screening version of the BSD III.

In addition to its use with infants and children, the BSD III has become a test of choice with adults who are developmentally disabled. This is because cognitive and intelligence tests for adults lack the discrimination ability to measure cognitive and intellectual functions which vary from the norm. Decades ago, adult tests were able to do this, but new versions of adult tests lack this precision. Is it appropriate to use materials meant for infants and toddlers when assessing developmentally disabled adults? What emotional responses are evoked in loving parents when they see their adult son or daughter being made to work with materials meant for the very young? In Part II we will look at the historical reasons as well as the professional and human concerns regarding the use of the BSD III with adults.

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