Boundary extension and kids

We've posted on boundary extension before, here, here, and here, but we've never written about boundary extension and kids. Boundary extension is when we remember more of a picture than was actually shown to us, as if our mind is actively creating a portion of the image we didn't see, beyond its boundaries. A 2002 team led by John Seamon found that people of all ages experience boundary extension.

Some research has found evidence that boundary extension doesn't work for all images. We reported on a study by Andrew Mathews and Bundy Mackintosh suggesting that for emotional, arousing images, people with higher anxiety levels have less boundary extension than those with lower anxiety levels. Perhaps children also experience higher levels of anxiety when viewing emotional images. A team led by Ingrid Candel published the results of their study to test this hypothesis in the American Journal of Psychology.

They showed ten- to twelve-year-olds either neutral pictures (like bananas or an old tire) or emotional pictures (like a shark or a gun), then asked them to draw those pictures from memory. The redrawn pictures were carefully measured to see if their boundaries were larger or smaller than the originals (this is the method used by Helene Intraub and Michael Richardson in their pioneering 1989 study on the subject). Unlike Mathews and Mackintosh, Candel et al. found boundary extension for both emotional and neutral pictures—an average of 48 percent the size of the original for neutral pictures, and 46 percent the size of the original for emotional pictures.

Does this mean children don't restrict their focus on emotional pictures? There were a few differences between Candel et al.'s study and that of Mathews and Mackintosh. First of all, Candel et al. made no attempt to distinguish between mildly emotional and extremely emotional images. They did not separate the kids into high- and low-anxiety groups. And they used a different method—drawing, rather than choosing between different pictures. It's possible that one or more of these differences is what accounts for the disparity between results. It's also possible that kids simply react differently to emotional pictures than adults do.

Mathews and Mackintosh speculate that the lower boundary extension they found for high-anxiety people viewing extremely negative pictures was due to their inability to avert their eyes from the threatening picture. Perhaps children behave more like the low-anxiety group in Mathews and Mackintosh's study, and avert their eyes, thereby exploring more of the boundaries of the picture. It's also possible that Candel et al.'s pictures simply weren't negative enough for them to observe the effect. The disparity between these two results highlights the difficulty in psychological research, particularly when complex phenomena such as emotions, anxiety, or childhood are being studied.

Candel, I. Merckelbach, H., Houben, K., and Vandyck, A. (2004). How children remember neutral and emotional pictures: Boundary extension in children's scene memories. American Journal of Psychology 117(2), 249-257.