The Effects O F Stimulus Modality and Task Integrality: Predicting Dual-task Performance. and Workload from Singletask Levels

T h e inf luence of s t imu lus modali ty and task dif f iculty on workload and perform a n c e was invest igated in the current s tudy. T h e goal ums t o quant i fy the "cost" (in t e r m s of response t i m e and ezperienced workload) incurred when essentially serial task componen t s shared c o m m o n e l emen t s (e.g., the response to one init iated the other) which could be accomplished in parallel . T h e ezperimental tasks were based o n the "Fittsberg" paradigm; the so lu t ion t o a S t e r n B E R G t y p e m e m o r y task determ ines which of t w o ident ical FITTS targets are acquired. Previous research suggested that such func t iona l l y integrated "dual" tasks are performed with substant ially less workload and fas t e r response t i m e s t h a n would be predicted by s u m ming single-task c o m p o n e n t s w h e n both are presented in the s a m e s t imu lus moda l i t y (v isual) . In the current s tudy, the physical integrat ion of task e l emen t s ums varied (al though the i r f unc t iona l relationship remained the s a m e ) t o de t e rmine whether dual-task faci l i tat ion would persis t i f task componen t s were presented in dif ferent sensory modali t ies . ii was f o u n d that the cost of per forming the two-stage task was considerably less t h a n the s u m of componen t single-task levels when both were presented visually. L e s s faci l i tat ion was f o u n d when task e l emen t s were presented in di f ferent sensory modali t ies . These results suggest the impor t ance of distinguishing between concurrent tasks tha t compe te f o r l imited resources f r o m those tha t beneficially share c o m m o n resources when selecting the s t imu lus modali t ies j o r i n f o r m a t i o n displays. A g a i n ,