Originally published in United Academics Magazine on February 8, 2012.
How do people get lost and how do you find them again? Find out how our mental compass can drift and how search and rescue professionals use statistics to predict our whereabouts.
People get lost all the time, be it in the mall, in a new city, or more worrisome, in the woods or in a snow storm. What happens in the brain when we cannot find our way?
In his 2010 book “Why People Get Lost: the Psychology and Neuroscience of Spatial Cognition”, University of Stirling psychologist Paul Dudchenko suggests that people have an internal sense of direction or a “mental compass”. “It is not a magnetic compass,” he said (there is no consistent evidence that humans have a magnetic sense),” but an internal compass that anchors itself to the outside world. It usually is very good because we walk around familiar landmarks by which we can orient ourselves, but if we are someplace where there is no ability to correct it, our compass starts to drift.”
Many studies have demonstrated this. “The simplest experiment is having people close their eyes and walk in a straight line,” said Dudchenko. “People can’t do it. You can only do it for a couple of meters and then you start to drift either to one direction or the other, even though you think you are going straight.”
Walking in Circles
People who get lost indeed do walk in circles. In 2009, Jan Souman and his colleagues from the Max Planck Institute for Biological Cybernetics in Germany asked participants in their study to walk in a straight line through unfamiliar terrain (a large German forest and the Sahara desert in Tunisia) while being tracked by global positioning systems. Results showed that they were only able to keep a straight path when the sun or moon was visible. Without those external cues (for instance on a cloudy day) participants walked in circles without even noticing it (see image below). Souman suggested that small random errors in the various sensory signals that provide information about walking direction add up over time, causing a person perceiving to be walking straight ahead, to drift away from the true straight line.
Studies with rats and rhesus monkeys suggest that the neurons underlying our mental compass are so-called “head direction cells”. Dudchenko admits that the presence of these cells has not yet been recorded in humans but he argues that we are likely to have them because we share the brain structures containing these cells with the studied animals.
Aside from head direction cells pointing us in the wrong direction, there is a second way people can get lost: by the breakdown of their cognitive map. A cognitive map is a spatial representation of the outside world in our brain and is believed to reside in the hippocampus. Studies of people with a damaged hippocampus have shown that they have great difficulty learning the layout of new locations like a new town or a office building.
Interestingly, when it comes to having a “sense of direction”, there is quite a variation between individuals. Experiments with university students have demonstrated that people who rate themselves as having a good sense of direction are better at recalling the spatial layout of familiar environments, better at learning the layout of new places and better at following directions than people who rate themselves as having a poor sense of direction. What makes the good way-finders different from others is that they seem to make better use of salient landmarks like the sun or a prominent building and notice their surroundings more.
Searching in the Wilderness
Once people are lost, how do they behave? American search and rescue expert and neurobiologist Robert Koester has extensive experience with lost persons, many in remote locations, and wrote a book on the subject in 2008.
He distinguishes three phases. “First there is a navigational mistake, like taking the wrong trail. Then there probably is a gray period when things are not quite matching up,” he said. What often prolongs this “gray” phase is what Koester calls the “bending of the map”. “You only pay attention to the facts that tell you that you are right and you ignore everything that tells you that you are wrong,” he said. One of Koester’s favorite examples is a man who went hiking in New Zealand and said: “Boy it’s awfully funny how in New Zealand the sun rises in the West instead of the East.”
In the third phase, people realize they are lost. According to Koester this often causes – at least in wilderness situations – the classic fight or flight response including the release of adrenaline. “Your blood pressure and heart rate are going up, your hands may start shaking, you may start to get nauseated, and you may have a fear that you are going to die,” Koester said. “Essentially, all the things described in an anxiety disorder are going on even though it is technically not one because the definition of an anxiety or panic attack is that there is no actual real harm or threat, and if you are lost in the woods there may be a real harm or threat.”
For most people when they get lost, that rush of emotions and symptoms is usually fairly short. “Most people will eventually settle down and come up with a plan of some sort of how they are going to get themselves out of the situation. Some plans are good and some plans are bad,” said Koester.
What to Do when Lost in the Wilderness?
Survival experts generally advice the following five steps when lost (assuming you did not bring your cell phone with built-in GPS):
- S.T.O.P. Stands for Stop (take a deep breath, sit down and calm yourself), Think ( from now on you will think before any further action), Observe (take a look around and assess your situation and options) and Plan (prioritize your immediate needs and make a plan).
- Stay put. You are much easier to find by others if you stay in one place than when you move around. You also save valuable energy and prevent (further) injuring yourself this way.
- Signal. Make noise (blow a whistle, bang rocks together, shout), make your location visible from the air, use a signal mirror, build a fire, mark your trail if you have to move (use wads of moss, broken branches etc.)
- Shelter. Find a location out of the wind/rain/snow, make a bed of tree boughs and leaves, build a fire, build a roof (if necessary) from any material you can find.
- Water. Find a source and drink. Don’t worry about food. (You can go over 4 weeks without eating -much longer than the average survival situation- so don’t waist energy looking for food unless it is there for the picking).
Research by Kenneth Hill, a psychologist and member of the Halifax search and rescue team, showed that people who become disoriented, generally rely on a handful of methods to find their way back. These include route traveling (taking unknown paths), route sampling (trying out parts of different paths from a known intersection), and view enhancing by going to higher ground and backtracking. Some of the less effective methods include random traveling (following the path of least resistance) and direction traveling where the lost person is convinced safety lies in one particular direction, going cross country and often ignores paths and sometimes even railroad tracks, power lines and highways leading in the “wrong” direction.
Another common reorienting strategy is using folk wisdom like “all streams lead to civilization”, which are again, no guarantee of success. Hill writes that if you follow this principle in Nova Scotia, you will more than likely end up in a remote and bug-infested swamp. The best strategy – even if it seems somewhat passive – is staying put, so long as you can reasonably expect a search to be organized on your behalf in the very near future. Sadly, very few people apply this method of getting out of the woods safely. In his review of over 800 lost person reports from Nova Scotia, Hill found only two cases of people who stayed-put.
To make it possible to predict the behavior of lost persons, in 2002 Robert Koester helped to create the International Search & Rescue Incident Database. This extensive data collection contains valuable statistics such as: average distance traveled by lost persons, typical find locations, hours of mobility, dispersion angles and chances of survival . The data is divided by 41 subject categories including hikers, hunters, children, snowmobilers, and people with dementia, and takes into account different environments and climates. (See hiker statistics example). By now, the database contains over fifty thousand incidents from seven countries including the US, Canada, New Zealand, Australia and the UK and it is used worldwide by search and rescue professionals.
Example from the International Search & Rescue Incident Database
Distance from the search starting point within which lost hikers are found in 25%, 50%, 75% and 95% of the cases.
Koester’s statistics give cause for optimism about the chances of being found. He notes that 98% of search efforts are successful in finding the lost person and in 91% of the cases, the person is found alive. In addition, 50% of lost people are found within 3 hours of searching. So, it is comforting to know that despite our poor internal navigation capacity and our suboptimal way-finding strategies, most of the time, we will make it home alive.
References
Dudchenko, P. A. (2010). Why People Get Lost: the Psychology and Neuroscience of Spatial Cognition. New York: Oxford University Press. ISBN 978-0-19-921086-2
Hill, K. (1999). Lost Person Behaviour. Ottawa, Canada: National SAR Secretariat. ISBN 0-660-179471-5
Koester, R. (2008). Lost Person Behavior. Viginia: dbS Productions LLC. ISBN 978-1-879471-39-9
Souman, J., Frissen, I., Sreenivasa, M., & Ernst, M. (2009). Walking Straight into Circles Current Biology, 19 (18), 1538-1542 DOI: 10.1016/j.cub.2009.07.053
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