Why is it that most of us can remember our precise surroundings the moment that we first learned of JFK’s assassination, the Challenger explosion or the fall of the Twin Towers, but not say, what grocery aisle we were standing in when the phone call came to remind us to pick up milk? What is it about the timing—or more specifically, the coincidence with intense experience—that seals in visual memories more effectively? That’s the question that a new study from psychologists at the University of Washington set out to answer.
The study, published online today in the open-access journal PLoS Biology included a series of four experiments. In each experiment, which included distinct participants, Jeffrey Y. Lin and colleagues showed study subjects 16 photographs depicting familiar landscapes. The first time, participants merely looked at the images; the second time, they were also asked to focus on a number shown in the middle of the image; the third time, they also had to make note of an auditory cue as they looked at the images; and finally, they were shown images with a number in the middle, but told to ignore them and focus only on the scene depicted. Researchers found that, when shown an image later and asked to recall if it had been among those they’d already seen, subjects’ memory formation was consistently best when they had also been trying to concentrate on another task: in both the second and third experiments, which involved viewing numbers or hearing audio tones while the images were presented, subjects formed clearer memories than in the first experiment—when they were simply instructed to look at the photos—and than in the fourth experiment—when they were shown numbers in the center of photos, but told to ignore them and focus on the images themselves.
The findings suggest that it isn’t the novelty of what we’re seeing, but the experience that we are having while we look at something, that determines how well we store it away in our memories. Or, as the authors phrase it, the study results provide “evidence of a mechanism where traces of a visual scene are automatically encoded into memory at behaviorally relevant points in time regardless of the spatial focus of attention.” When it comes to making memories, timing is of the essence.