A novel clinical test of recognition reaction time in healthy adults

We evaluated a clinical "go/no-go" reaction time test (recognition RTclin) that is portable and does not require a computer, and used it to quantify the effect of age on recognition RTclin test scores. Fifty-two healthy adults 19-83 years old completed simple and recognition RTclin testing. Simple RTclin was measured as the elapsed time from initial release of a suspended vertical shaft by the examiner until its arrest by participant pinch grip. Recognition RTclin was similar except that a light on the apparatus randomly illuminated in 50% of the trials to signal the participant to arrest the device. To help interpret the RTclin results, we partitioned them into premovement time (PMT) and movement time (MT) using an optoelectronic camera system that is not ordinarily part of the RTclin test. Recognition RTclin scores were significantly slower than simple RTclin scores, with 71% of the prolongation attributable to PMT. While simple RTclin test scores correlated with age, recognition RTclin scores did not. A strong negative association between recognition RTclin accuracy and age was found. Recognition RTclin is feasible to measure in healthy adults and appears to represent a portable, computer-independent measure of cognitive processing speed and inhibitory capacity. Potential applications include assessment of brain injury, dementing illness, medication side effects, fall risk, and safe driving.     

Parallel Processing Response Times and Experimental Determination of the Stopping Rule

It was formerly demonstrated that virtually all reasonable exhaustive serial models, and a more constrained set of exhaustive parallel models, cannot predict critical effects associated with self-terminating models. The present investigation greatly generalizes the parallel class of models covered by similar "impossibility" theorems. Specifically, we prove that if an exhaustive parallel model is not super capacity, and if targets are processed at least as fast as non-targets, then it cannot predict such (self-terminating) effects. Such effects are ubiquitous in the experimental literature, offering strong confirmation for self-terminating processing. Copyright 1997 Academic Press. Copyright 1997 Academic Press