Yet another amazing feat by the human brain

Every day the human brain commits vast amounts of information to memory. No single man-made machine can match the immense storage capacity contained within the brain’s approximate 100-billion neurons. How our most complex organ sifts through a steady stream of sensory input—deciding what is important versus what is trivial—is an area of intense scientific investigation.

In a study recently published in the journal Plos Genetics, scientists report that memory formation is enhanced by attention-demanding tasks. A group from the University of Washington, led by Dr. Jeffrey Y. Lin, presents a set of experiments that test participants’ memory during image recall.

In each experiment, participants are shown a series of urban and rural scenes and asked to correctly indicate if an image has been presented in the set of pictures. A fifty-percent correct answer rate, or that which could be achieved by simple guessing, would indicate little to no memory is formed. In the first experiment, Lin reports that participants are correct fifty-one percent of the time, indicating a lack of memory formation. However, in a subsequent test, Lin’s team pairs the scenery images with a black or white letter and asks participants to remember which letter is white. Surprisingly, even though the participants are not specifically asked to memorize the scenery in the images, the participants are able to correctly recall the scene with the white letter sixty-seven percent of the time, indicating a statistically significant result.

This finding suggests that the act of performing an attention-demanding task causes the brain to enhance the memory of what surrounds the target of focus (i.e. the urban and rural scenes surrounding the letter). Lin’s team finds a similar result when the scenery images are paired with two auditory tones, with participants correctly remembering the image paired with the target tone almost sixty-five percent of the time.

To verify that memory is enhanced by the focused task, and not by the presentation of a novel stimulus, (in this case a newly colored letter), participants are shown the images with letters again, but are told not to take note of the white letter. In this case, no memory enhancement is observed, suggesting that the attention-demanding task itself enhances memory.

The Bottom Line: The brain can automatically perceive and encode visual stimuli in attention-demanding settings, suggesting that our brains are wired to involuntarily remember more about our environment when we are presented with a situation that requires focused attention.

Reference: Lin JY, Pype AD, Murray SO, Boynton GM. (2010). Enhanced Memory for Scenes Presented at Behaviorally Relevant Points in Time. PLoS Biol. Mar 16;8(3):e1000337

Plos Biology is an open-access journal. This research article can be downloaded at:
http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000337