Lost Person Behavior
The average lost person can travel about 2 miles per hour on foot, yet statistics indicate a large percentage are found within a radius of 3 miles of the PLS (Point Last Seen) in a wilderness search. Studies also indicate patterns that act as a guide for the search strategy based on age and various circumstances, but the individual's past history is also taken into consideration and might identify something pertinent, like the potential to use a form of transportation rather than walking. Terrain, weather, etc. may be important factors. The search plan will consider Probability Zones, and adjust from there. Personnel deployed in the field must take typical lost person behavior into consideration during a Search. A comprehensive subject profile is invaluable both for search management strategy and field personnel. Pertinent information will be provided during briefing of assignments, but the Command Post also relies on knowledgeable input from the field.
Appropriate behavior for a lost person is normally to stay where you are, and try to remain visible during daylight hours. Children may have been taught to "hug a tree." If prepared, the person may carry a whistle to try and attract the attention of rescuers. However, many people will continue to wander to try to somehow save themselves. While some will try to stay on some form of path or follow water's edge, a person looking for a shortcut to where they think is a logical destination will leave the trail. In this kind of circumstance research indicates 62% would leave the trail. This kind of statistic is critical awareness for searchers in the field so they will specifically look for clues beyond the more obvious trail vicinity.
Influencing factors for the lost person's behavior might be fear of darkness, animals, being along, suffering or death. Weather may be a primary factor. Some lost subjects may attempt to find or create some kind of shelter, but may not remain there. It isn't unusual to find discarded equipment or clothing as the person becomes more disoriented.
The initial search of an area might focus on certain zones based on probabilities. That may include using the Matson Theory, where search management personnel will use behavioral patterns common to the missing person to assign "best guess" percentages to different areas and focus on the highest consensus areas first.
A subsequent search might expand the original zones, or be more detailed within a zone. Search Teams should understand their assignment and cover the designated area as deployed, but also report any good potential search areas beyond the scope of that assignment. The Command Post may want the Search Team to modify an d adapt according to what is observed in the field. A searcher with a good understanding of lost person behavior may provide valuable insight from the field that influences the search assignment, or even modifies the search strategy.
A summary of studies on lost person behavior includes: (This refers to primarily to wilderness or rural SAR)
- Some lost people will climb the highest hill in an effort to better see the area. The don't consider that there may be trees in the way obstructing their view. Or the may carry a cellular phone or 2-way radio and be seeking higher ground for a better transmission. Check areas of higher elevation for tracks or other clues.
- Many people will ignore a trail and follow their own logic based on line of sight. They think they'll find a road or "civilization" faster. They don't anticipate finding rough terrain, a cliff, a river, etc. in their path. Watch for tracks or other clues to indicate someone leaving or crossing a trail. Do a perimeter search or quadrant search along a wider area of the trail.
- If a lost person finds a trail, they might start running. They believe they are running back to camp or their vehicle, but might actually being running away from that destination. Watch for lengthened strides that could indicate the person believes they have identified the direction of their destination.
- A lost person will rarely reverse direction on a trail.
- The majority of lost people will travel downhill and/or downstream
- Those who travel downstream will usually end up in an impassable terrain long before they reach anything resembling civilization.
- Many lost people will travel at night, even without a flashlight.
- Most lost people will stay on a trail if they aren't convince they are heading in the right direction.
- Lost people rarely move randomly. Movement indicates they probably believe they are heading in the right direction...but that may well be the wrong direction.
Mental/emotional Aspects of the Lost Person
Consider the likely emotional state of the lost person during the search. Also consider the background of that person and possible skill sets that would encourage people to try and save themselves. There might be variation in Search Methods or search strategy in the field adjusted to the anticipated behavior of the missing person. Interview information regarding that missing individual should reveal particular details that would guide the type and focus of the subsequent search.
Despondent and/or Suicidal
A SAR for a despondent/suicidal person must ALWAYS considered an emergency. Despondent/Suicidal behavior of the missing person includes particular issues to consider:
- The person is considering death, and may not protect him/herself from the elements. If not found quickly, this person may die from exposure. This kind of SAR is a greater emergency because the individual is not intent on saving his/her own life.
- Note that 50% of adolescents consider suicide before adulthood.
- The person generally will not respond to Searcher's calls, and may try to hide. Rely more on visual clues and less on expecting any response to a Sound Search. Be alert for areas of possible concealment to search.
- Suicidal subjects generally don't travel far, but usually seek a more scenic location where they can sit and meditate.
- Be prepared to offer emotional support when the subject is located.
Delusional/Disoriented Missing Person
A missing delusional/disoriented subject is difficult to predict. Some may exhibit behavior similar to the despondent subject by hiding or otherwise evading the Search Teams. Others may not even recognize they are considered "lost" and may not understand that they are the reason there are Searchers in the vicinity. Behavior varies. SAR strategy for this kind of missing person will try to adjust to anticipated behavior based on input of family members, health care professionals, etc., who know the missing subject. Alzheimer's Disease in particular has behavior patterns, and often the missing person is a repeater that may establish a pattern.
However, searchers should also be aware a change is mental health might be temporary, caused by the environment, etc. For example, at high elevations some people become disoriented to varying degrees as a result of what is commonly called altitude sickness. Other health issues like hypothermia and heat exhaustion can also cause a person to become disoriented. The quality of decision-making will also be reduced as a missing person goes for a longer period without food or water, becomes more fatigued, etc. If the missing person is on medication - particularly with new medication or failing to take medication - that may also have direct impact on resulting behavior.
The Disappearing Act
For one reason or another, the missing person may plan not to be found. The planned disappearance may be related to crime, evading some form of stress in his or her life, etc. this person may intentionally attempt to confuse trackers and Search Dogs.
If the tracker sees clues that make him or her suspicious the missing person is intentionally avoiding being found, this should be reported to the Command Post.
Change in Behavior
Searchers should be alert to the potential that a situation that started as a missing person search may evolve into a criminal situation, or may have been a crime from the outset. There may be unexpected threats to the lost person on other factors that could cause a change in their behavior. A tracker may see something that would impact the search strategy.
Make a note of clues that may appear to be unrelated, and attempt to avoid contaminating that clue in case it is later considered evidence. For example, if tracks indicate a sudden change in the missing person's behavior consider that there may have been an outside influence like the appearance of another person that resulted in flight, etc. If anything suspicious is observed, the Command Post should be notified immediately. For example, if the person may hide or run from Search Teams so the search tactics must be adjusted.
Additional threats to the missing person may also come from the environment. Make note of animal tracks, snakes, etc., that may have influenced or come in contact with the missing person. A tracker may also notice a change in the way a person is moving, perhaps indicating an injury or change in mental or physical health. Reduced judgment resulting from heat, cold, fatigue, altitude, etc., is factors that may be more quickly recognized in the field. A behavioral change noted in the field by trackers and reported to the command Post may help define or revise the search strategy.
Alzheimer's Disease Lost Person Fundamentals
- 70% will wander, 83% are repeat cases
- Subjects are often found in the immediate nursing home facility or residence area
- May not call for help or respond to searcher's shouting, and may actively hide
- Most are elderly, less capable of self-care, and will more easily succumb to issues in the environment
- 89%found within 1 mile of PLS (Point Last Seen)
- 67% may cross or depart from roads
- Usually found a short distance from the road, with a travel distance of .5 miles
- Tend to wander into brush/bramble regions and get stuck
- Usually found near or in creeks or drainage ditches
- May attempt to travel to a former residence or favorite place
While true of most lost/found persons, the Alzheimer subject may be particularly in need of reassurance. And as with any found subject, that person should not b left alone to potentially wander off again.