INTRODUCTION

If you thought personality was difficult to define and a topic filled with questions for which there are no agreed-upon answers, then cognition, and more specifically intelligence, is an even more convoluted topic.

Not only is there no agreed-upon definition of intelligence, but the discoveries and findings of cognitive psychology are coming so fast that any snapshot of the field would be outdated even before it is developed. Fortunately for textbook writers, the field of testing is in many ways slow-moving, and practitioners do not readily embrace new instruments, so much of what is covered in this chapter will not be readily outdated.

In the field of intelligence, a multitude of theoretical systems compete with each other, great debate exists about the limits that heredity and environment impose upon intelligence as well as substantial argument as to whether intelligence is unitary or composed of multiple processes (A. S. Kaufman, 1990; Sternberg, 1985; 1988a; Wolman, 1985). It is somewhat of a paradox that despite all the turbulent arguments and differing viewpoints, the testing of intelligence is currently dominated basically by two tests: the Stanford-Binet and the Wechsler series.