Once, long ago, I used to be in a radiology department in a famous hospital. I liked radiology quite a bit and even before becoming a doctor I worked in them. Later I did research on the kinds of errors radiologists make when they read x-rays. One of the errors that was extremely well known even 40 plus years ago (although that didn’t prevent it from being made with dismaying consistency up to and including today) was something called “satisfaction of search error.” In essence, it meant that once one abnormality was found on an x-ray, there was an increased chance of missing a second, unrelated one.
Radiologists have known about this for a long time, but apparently people in other fields haven’t. It’s not just medicine. It is plausible to think that any task involving searching through a constantly changing and complex cognitive field might also have this problem. Like screening luggage at the airport. According to a paper in press at the Journal of Experimental Psychology: Applied by Fleck, Samei and Mitroff, this is exactly what we can expect:
This new study examined whether that concept also applies to airport-security scans, and it seems that it does. In fact, the researchers found, the problem may be worse among luggage screeners because they are under more time pressure than radiologists. They write that scrutinizing luggage for toothpaste and hair gel may come “potentially at the expense of finding additional targets which may be better concealed and less frequent, such as scissors, box cutters, or pocketknives.”
The study was conducted using Duke University students and computer simulations. So it’s reasonable to ask whether trained airport-security personnel would fall victim to the satisfaction-of-search issue. But, according to the authors, previous research suggests that, no matter how much training you have, the problem persists.
Obviously there are valid reasons for being concerned about potential weapons disguised as everyday items. But there may be a cost to being too careful. (Tom Bartlett, Percolator Blog at The Chronicle for Higher Ed)
The hair gel/liquids restriction was stupid from day one, a typical case of Bruce Schneier’s “Security Theater.” It’s been obvious that much Security Theater hurts us by being costly, inconvenient and ineffective. Now it appears it can also make us less secure.
What will they think of next? NB: that’s not a rhetorical question.