Meta-Analysis of Multiple-Task Performances: Cumulating the First two Decades of Research Findings across Studies

Abstract

Meta-analytic procedures were used to cumulate research findings across studies of multiple-task performances published between 1965 and 1985 (inclusive). Exhaustive literature search yielded 94 reports of studies of multiple-task performances that were sufficiently detailed to be statistically combined using the Hunter-Schmidt-Jackson procedure. These studies yielded a total of 202 statistical values and a total subject N of 3091. Meta-analysis was performed overall (resulting in a significant test statistic) and then as a function of secondary task (13 types), primary task (18 types), and specific secondary-primary task combination. (The secondary tasks were Choice Reaction Time (CRT), Classification, Detection, Memory, Mental Math, Monitoring, Motor Response, Problem Solving, Reaction Time, Shadowing, Speech, Task Battery (Multiple Tasks), and Tracking; the primary tasks were Association, CRT, Classification, Decision Making, Detection, Driving, Flight (Simulation), Memory, Mental Math, Monitoring, Motor Response, Problem Solving, Reading, Shadowing, Sketching, Speech, Tapping, and Tracking.) Ten external variables (Carbon Monoxide, Control-Display Compatibility, Drug Use, Feedback, Intelligence Tests, Neuroticism, Noise, Rating of Job Performance, Sinus Arrhythmia, and Temperature) as correlates of multiple-task performances were also examined. A generally positive relationship between secondary task performance alone and in combination with the primary task was found, along with moderating effects of secondary task type and primary task type. No substantial variation of results within a given combination of secondary and primary task types occurred in most cases, although four external variables (Carbon Monoxide, Feedback, Noise, and Temperature) displayed within-factor variation of results. All results were discussed in terms of integration of the past literature and directions for future research.