PSYCHOLOGY OF COMPUTER USE .36. COMPATIBILITY OF TASK PRESENTATION AND TASK STRUCTURE IN HUMAN-COMPUTER INTERACTION

Task presentation concerns how information is presented. Previous stud ies of differences between the alphanumeric presentation and the graph ic presentation of task information have reported inconclusive or inco nsistent results because the effect of task structure and its interact ion with task presentation have been ignored. This study explored the compatibility between task presentation and task structure. Two forms of task presentation, namely, the alphanumeric presentation and the gr aphic presentation, were examined. Two types of task structure, namely , linear procedural and conditional branching, were examined. A nested factorial experiment was conducted for a comprehension of computer pr ograms. Program code written in C programming language was used as the alphanumeric presentation oi computer programs. Flowchart was the gra phic presentation of computer programs. 32 subjects participated, 16 b eing exposed only to the alphanumeric presentation, while another 16 w ere exposed only to the graphic presentation Each subject performed ta sks with both types of structure. Four measures mere collected, task c ompletion time, number of errors, subjective rating of task difficulty , and subjective rating of mental workload. Analysis indicated signifi cant interaction between presentation and the structure of task on all four measures. On each measure, the graphic flowchart presentation wa s more compatible with the conditional branching tasks than the alphan umeric program code presentation. On the two subjective measures of ta sk difficulty and mental workload, the alphanumeric program code prese ntation was more compatible with the linear procedural tasks than the graphic flowchart presentation.