Physiological correlates of mental effort as manipulated through lane width during simulated driving

—Previous studies suggest that physiological effects
of mental effort as manipulated trough cognitive task difficulty
differ from effects of mental effort as manipulated trough a
visuomotor task such as lane keeping in simulated driving. Most
notably, heart rate increases with mental effort in the former but
not in the latter task. EEG seems to be indicative of mental effort
in both cases. In previous research [1], Brouwer and colleagues
examined effects of mental effort as manipulated in a cognitive
(memory) task on a range of physiological signals. In the present
research we examine the same types of physiological signals using
the same kind of analysis in a visuomotor (simulated driving)
task. In this case, mental effort was manipulated using wide and
narrow lanes. Effects of task difficulty on both subjective mental
effort and behavioral variables were comparable across tasks.
Effect of task difficulty was replicated for respiration frequency
and to some extent for EEG alpha activity. However, in contrast
to the cognitive task [1], skin conductance and heart rate related
variables were not significantly affected by task difficulty in the
current visuomotor task. We argue that differences in visual
attention and cerebral energy demand between the types of tasks
may be at the basis of this.