The scientists also recruited participants who were depressed, at least to some degree, and that group recalled far more negative memories, especially among those with a weak browser. That suggests a relationship between depression and recall, although this work does not determine if the negative memories resulted from depression, or if depression partly stemmed from the flood of sad memories.
A good browser might help keep negative memories, and possibly depression, at bay.
"Without such a mechanism, people might find themselves increasingly inundated by disruptive, and often painful, autobiographical memories," Storm and Jobe conclude.
In an earlier study, Storm described the power of memories this way:
"These things could completely overrun our life and make it impossible to learn and retrieve new things if they were left alone, and could just overpower the rest of memory."
By the way, we may prefer happy memories to sad recollections, but that doesn't mean sad memories are weaker. Psychologist Elizabeth Kensinger of Boston College found that we may not like sad memories, but we retain them in vivid detail.
Kensinger, who uses brain scans to study her subjects, said in releasing her study that someone who has been confronted by an assailant with a gun is likely to remember exactly what the gun looked like, even though other details may be hazy. She thinks that's probably because no one wants to be in that situation twice, so remembering the gun is likely to keep us on alert in the future.
"These benefits make sense within an evolutionary framework," she wrote.
However, it's probably not a good thing to be constantly haunted by a man with a gun. That's why, according to a growing number of researchers, our brains need good browsers. They help us keep sad, and even just the mundane, memories on the back burner.