What types of images are you more likely to remember over the short-term? Pleasant? Bright? Arousing? Disturbing? One method of testing short-term visual memory is to flash a rapid series of pictures, then ask viewers which ones they saw. The pictures are shown so quickly that it’s impossible to remember them all. Click on the image below to view a movie (Quicktime required). Wait for the entire movie to load, then watch it. You’ll see 12 photos rapidly flash by. Play it twice, but no more.
Other than the first and the last one, did you remember any? I’ll put a quick test below (fair warning — there’s a bit of nudity in the test images).
[make sure you play the movie before you scroll down!]
So which pictures really were in the movie? I’ll give the answers below. The larger question, of course, is which type type of pictures viewers are more likely to remember, and why. Vera Maljkovic and Paolo Martini have designed a much more systematic test.
They showed viewers hundreds of pictures in rapid serial visual presentation (yes, that’s abbreviated RSVP) just as I did above, in sets of 10. The time each image was presented varied from about 1/100 of a second to four full seconds. Of course, the most important factor in memory for a picture was how long it had been viewed, but does the type of picture matter too?
You might guess that viewers are more likely to remember a nude woman than a minivan, but what about a firing gun, or a corpse? Each of these pictures offers viewers a different emotional experience, and previous research on emotion has consistently found that this experience varies in two different ways. Photos (and other stimuli) can be more or less arousing, and they have a positive or negative valence. These dimensions of emotion are independent, as this chart shows:
Photos can be positive and arousing (sex), or negative and arousing (death). Moderately arousing positive pictures include children and flowers, while moderately arousing negative pictures include smokestacks and graveyards. Innocuous objects like irons and file cabinets aren’t arousing at all, and offer neither a positive or negative valence.
So, which pictures are remembered best? As it turns out, it depends both on the picture type and how long the picture was viewed. When just arousal is considered, the data maps out how you might expect:
More arousing pictures are remembered better, no matter how long the pictures were viewed. But when valence is subjected to a similar analysis, a different picture emerges:
For short viewing times, positive photos are remembered better, but for longer viewing times, negative photos are remembered better.
So just as arousal and valence have different effects on emotional experience, they also have different, independent effects on visual memory. For short viewing times we remember positive, arousing images best, but for longer viewing times we remember negative, arousing images best.
Was our demonstration movie able to replicate this effect? The last three images tested were all present in our movie. Maljkovic and Martini’s results would suggest that the reclining nude Venus would be remembered best (positive, highly arousing), followed by the firing gun (negative, highly arousing), and the minivan (neutral, not arousing). How did your results compare?
Maljkovic, V., & Martini, P. (2005). Short-term memory for scenes with affective content. Journal of Vision, 5, 215-229.