Research Training Project: Visual search for threatening and non-threatening objects

Szwed, Mateusz, Bryan Kloss, Reniseya Williams, Ervis Fama, and H. Greene

We present results from preliminary work on our efforts to better understand how potentially threatening  and non-threatening objects are localized when they are embedded in clutter.  This sort of task is faced regularly by airport and law enforcement personnel.  Some studies suggest that biologically-related objects that are strongly associated with potential threat (e.g. a picture of a snake, or angry face), grab attention when they are embedded within non-threatening objects.   More generally, the evidence is that  objects associated with strong emotions grab attention.  It may be that when we search for potentially threatening objects, we are more sensitive (from experience) to their particularly distinguishing features than to comparable features in non-threatening objects.   For example, if one has a history of strongly associating snakes with threat, snake  representations in the brain might be more strongly activated than if one did not have such a history.   


What about man-made objects of threat (e.g. guns, knives)?  Do they grab our attention?  We conducted a preliminary study in which we hypothesized that a potentially threatening object would be found faster than a non-threatening object, especially among non-threatening distractor objects.  Superlab4.0 software was used to present search displays, and we measured participants’ reaction time to indicate that the target had been found.   Two results are of interest: (i) The non-threatening target (a shoe) was found faster than the threatening target (a revolver)  irrespective of the nature of the distractors (threatening or non-threatening);  (ii) the threatening target (a revolver)  was found faster when it was  embedded within non-threatening distractors than when it was embedded within threatening distractors ( a grenade, a knife, etc).


Limitations of this preliminary work, and implications of this kind of experiment are discussed in the presentation.