For most of us, driving to work will be the riskiest thing we do today – and the risk is higher for drivers under 30! Road traffic injuries are the eighth highest cause of death worldwide and the leading cause of death for people aged 15-29. In addition to this, 50 million people a year will experience a non-fatal injury from a road traffic crash. And the consequences of those crashes will place significant demands on the health care system; not to mention the workforce. With driver distraction accounting for nearly 50% of road crashes, cognitive factors in driving, such as attention and perception, are important areas of investigation.
When we look at these cognitive factors, we tend to focus on errors, and in driving inattention is just one aspect. Another significant factor is an incorrect interpretation or judgement – such as seeing a light as green when it was red. With any task that requires intense concentration, like driving, this is fairly common, we can be looking directly at something and yet still not “see” it. And it happens a lot – we can’t find our keys, phones, wallets, when they are right in front of us. But more alarmingly, pilots overlook other planes, submarines miss fishing vessels, and drivers fail to see pedestrians, motorcycles, road signs, or flashing lights. Why might this happen you ask? Well to put it simply, we weren’t expecting the keys, remote, pedestrian, to be in that location so we simply are not attending to it.
In our regular environments, there are millions of potential stimuli for us to perceive; and interpreting them all would be overwhelming. When driving, this environment becomes more complex and overwhelming as the environment is not only changing constantly, but other road users are unpredictable. Combine this with the intricacy of operating a vehicle, and it is not surprising that our cognitive systems can become overloaded and we miss important features. One way we can reduce the demand on cognitive resources, and help us know where to look, is to rely on our previous experience – we create ‘environmental templates’.
These templates guide our interpretation of the environment and influence our expectations of we are going to encounter, based on what happened has happened before. We direct our attention to what was important to us in the past and when elements are missing, we can fall-back on these templates to ‘fill in the blanks’ and not bother resources on irrelevant or unnecessary details. Over time, we are constantly improving our template for different situations and updating it based on each encounter. It becomes a bit of a vicious cycle – we rely on the template to influence where and how attention is directed and this then influences how the environment is interacted with; this both reinforces and modifies the template.
Although helpful for reducing cognitive load, using these shortcuts can have negative consequences when incorrectly applied or when we are in a situation that is drastically different to one we have encountered before. These consequences are amplified if we continually apply ill-fitting templates.
If we consider this in the context of searching the road while driving; the template for a particular environment can have a significant impact on where attention is directed and what searching strategies are employed. How an individual will direct their vision in a known environment will drastically differ from an unknown or unfamiliar one.
When driving down the road in Australia, for example, we know to expect cars to be passing in the opposite direction on our right, and pedestrians to be on the street to our left. This forms part of our general road template. If we are travelling along a road we have travelled many times before, we will apply the template for that specific road and it will ‘tell us’ where to look. If something changes in the environment, even something as small as say a pedestrian appears when a driver was not expecting them to be there, we may not notice the change in the environment – even if we are directly looking at it!
So, the more experience we have with a particular environment, the easier it is for us to interpret it – BUT it could also mean that we are at risk of more attentional errors.
Currently the Centre is conducting longitudinal research to monitor how drivers modify these templates over time. For more information on this research project, and others like it, contact Rachael (rachael.wynne@research.usc.edu.au)
Rachael Wynne is a PhD candidate in the Centre for Human Factors and Sociotechnical Systems
Centre for Human Factors and Sociotechnical Systems 