Automation in the car is becoming progressively more sophisticated and we are
now approaching a critical junction, where vehicles will be capable of taking care of all
aspects of driving but with the expectation that the driver will promptly respond to a
request to take-over. With drivers already engaging in a variety of non-driving tasks, it
becomes crucial to evaluate the assumption of their readiness to intervene. While
simulator studies have partly addressed this expectation by comparing different non-
driving tasks, no research has tried to systematically vary the attentional demands of
the non-driving tasks and measure their impact on the take-over process. Here, aided
by the conceptual framework provided by Perceptual Load Theory, I explore two
different scenarios showing how manipulation of attentional load in the non-driving
task might hamper drivers’ ability to execute different aspects of the take-over process.
While testing was performed entirely in the laboratory, each experiment employs tasks
designed to be relevant proxies for both the non-driving tasks and the take-over
request. In Chapter 2, I present two experiments in which participants are asked to
watch a sequence of natural scenes of varied perceptual load – the non-driving task –
while monitoring for the occurrence of an auditory stimulus – the take-over request.
High perceptual load was associated with reduced detection of the auditory stimulus.
The three experiments reported in Chapter 3 instead aim at understanding the extent
to which high attentional demands right before a task switch might hamper the ability
to correctly process and respond to the motion of other vehicles, assessed with the
use of random dot kinematograms. A high level of perceptual load was reliably
accompanied by slower responses to the motion stimuli. Finally, in Chapter 4 I
describe an fMRI experiment looking at possible neural contributions to the reaction-
time delay observed in Chapter 3
