The aim of this study was to answer two questions: (1) Does communication with a phone partner require more attention than communication with a passenger?; and (2) Is the amount of attention that is required independent of the difficulty of the communication and/or the difficulty of the driving task? To answer these questions 37 students performed a dual task. This task consists of a tracking task which imitates the driving task and a calculation task which imitates the communication. The calculation task was either presented by the experimenter, or by a headphone (factor Partner). The calculation task has three levels of difficulty: non, easy or difficult (factor Communication). The tracking task has two levels of difficulty: predictable or unpredictable (factor Complexity). The analyses show that there is a main effect of Partner but that there is no interference between Partner and the other two factors, Communication and Complexity. This means tat the influence of Communication and the influence of Complexity are equal in the telephone condition and the passenger condition. Furthermore, there was an interaction between Communication and Complexity. The effects of Communication is stronger in the unpredictable condition than in the predictable condition. The conclusion is that, while being engaged in a driving task, communication with a telephone partner requires more attention than communication with a passenger. However, this effect can not be explained in terms of differential interference since there also was a difference between phone partner and passenger in the no communication condition. The effect of Partner can be account for by assuming that wearing a headphone disturbed the subjects in performing the task and/or by assuming that the physical presence of the experimenter motivated the subjects to do their best. (A)
Abstract