ABSTRACT
The focus of this chapter is at once broader and narrower than the issue of speed and error scores that I was asked to address. I discuss speed and error later, but first I take a broader look at the more general issue of how information-processing psychology can contribute to the measurement of individual differences, and why its impact has been far less than many of us expected it would be. The reasons, I believe, are rooted in basic assumptions about how performance can be decomposed into component processes, and what effect this decomposition has on the estimation of individual differences.
