CREST Guide: Finding hidden targets

finding hidden targets

What can influence our ability to find hidden targets? Based on research by CREST researchers Nick Donnelly, Anne Hillstrom and Natalie Mestry, this guide presents an overview of some of the difficulties in detecting hidden targets.

Sometimes the difficulty of finding a target lies in the similarity of the target to other objects or to the background, as well as in the complexity of the background. Our eyes are naturally drawn to regions with the most noticeable disruptions in colour, brightness or other features, and so when there are many of those regions in a scene, the target will be more difficult to spot. Camouflage that matches markings and colour of a target with markings and colour of the background makes the target less obvious.

The good news about searching for a camouflaged target is that practice at breaking one kind of camouflage seems to develop skill at breaking other kinds of camouflage.

When people search through a scene for a target they know will be camouflaged, they have difficulty suppressing their natural tendency to look at objects that stand out and so could not possibly be targets.

Although suppressing the visibility of object edges is central to how camouflage works, sometimes this works by presenting misleading edges. This is done by including quite bold changes in pattern near some of the edges of the target, distracting people from seeing the real edges.

The good news about searching for a camouflaged target is that practice at breaking one kind of camouflage seems to develop skill at breaking other kinds of camouflage.

Unseen objects

Targets may be difficult to spot because other objects have to be moved away or opened in order to see the target. Consider searching for your keys. Although sometimes they are found in plain view, other times they are in other rooms or are accidentally covered up or left in pockets or bags, in which case the search is more difficult.

Where we expect a target to be strongly affects how we first search a scene. If the target isn’t found in an expected place, we move on to considering other plausible locations for them. If the target is not visible, that means using memory and reasoning to figure out where to look. The physical and mental effort required to search means that without training, searchers will not search thoroughly.

You can read more on this topic by downloading the guide here 16-027-01-1.pdf. The guide will take two minutes to read. This guide is one of a series on detecting detect rare, hidden, or non-salient targets. You can read the other guides here.

As part of CREST’s commitment to open access research this guide is available under a Creative Commons BY-NC-SA 4.0 licence. For more details on how you can use our content see here.