Separable effects of factors on speed and accuracy: Memory scanning, lexical decision, and choice tasks.

Contends that experimental factors selectively influencing serial mental processes will have additive effects on RT and log percent correct. Further, if such factors have additive effects on RT in one experiment, they will also have additive effects in an experiment with different error rates. The contention is illustrated in a memory-scanning task reported by B. L. Lively (see record 1973-06015-001), a choice task reported by S. P. Shwartz et al (see record 1978-11552-001), and a lexical decision task reported by R. E. Schuberth et al (see record 1982-00388-001). Findings show that factors had additive effects on RT, only if they had additive effects on log percent correct, except for the speed-payoff condition in Lively's experiment. It is suggested that in this condition, the process durations were not stochastically independent. Four appendices illustrate the calculations. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)