A professor in one of my statistics classes warned that the human mind can play tricks with what we think are straightforward choices on their merits.
His example was the lineup where a set number of options are presented one by one — say, five choices of a sandwich for your lunch today. You have to make your final decision on Option 1 (the BLT) before you know anything about Option 2 and so on.
Here’s where your mind starts to play tricks on you: You really like BLT’s, but still pass on Option 1 because something better might come along. If you get all of the way to Option 4 (peanut butter and jelly), you take it even though it’s not your favorite — because your last chance, Option 5, might be chopped liver or something you find equally disgusting.
Researchers at Duke University studied a different mind game — one they suspected could compromise airport security.
The concept they explored is known in medicine as “satisfaction of search.” If radiologist reading X-rays found one abnormality, they tended to miss a second one. They thought they were finished and moved on to the next patient’s X-ray.
Might “satisfaction of search” also compromise airport security, the Duke team wondered.
In other words, is a security employee who finds an oversized bottle of shampoo in Traveler 1’s carryon luggage likely to move on to the next traveler and miss the box cutter that Traveler 1 also is carrying?
If so, the Transportation and Security Administration’s restrictions on liquids and gels could backfire. Security screeners would find that kind of contraband relatively easily and then be more likely to miss banned items that were less readily apparent.
“The liquids rule has introduced a whole lot of easy-to-spot targets,” Duke Professor Stephen Mitroff, who led the research, told e! Science News.
But, like the human mind, the answers to the basic question behind the research were complex.
In the study, published online in the Journal of Experimental Psychology: Applied, Mitroff and his group found that several different factors influenced “satisfaction of search.” One factor was the frequency of the easy- and hard-to-spot targets.
College students in their studies had no trouble finding the hard-to-spot targets in the presence of an easy one.
“But when the easy-to-spot item was two or three times more common, the subjects tended to overlook the hard-to-spot targets,” e! Science reported.
Another factor was time. The students in the experiments were significantly more accurate when the time for a search was doubled, even though they didn’t use the full time extension.
“It didn’t seem to do with time itself, but it seems to be the time pressure,” Mitroff told e! Science News. “When you have the impending time pressure of going quickly, you are more likely to miss a second target.”
The research suggests that security might be improved if the screeners worked in a space where they couldn’t see how many travelers were waiting in line and therefore didn’t feel pressure to hurry with the searches.