Learning statistical regularities can speed the encoding of information into working memory

Rhee, Konkle, Brady, & Alvarez

Observes automatically learn statistical regularities in their environment, and use these regularities to form more efficient working memory representations (Brady, Konkle, Alvarez, 2009). For instance, when colors are more likely to appear in certain pairs (e.g., red with blue), observers learn these regularities and over the course of learning are able to remember nearly twice as many colors. Here we investigated whether the benefits of learning hold only at the level of memory storage, or whether perceptual encoding of learned pairs becomes more efficient as well.

During the learning phase, 8 colors were presented (four bi-colored objects). After a delay, one location was cued with a thick black outline, and observers reported the color that was presented at the cued location. The colors were paired such that 80% of the time certain colors co-occurred (e.g., red with blue). Over the course of 9 blocks of 60 trials, the number of colors observers could remember doubled from 3 to 6, indicating that observers learned the regularities and formed more efficient memory representations. Next, participants completed a rapid perception task. On each trial, a single color pair was briefly presented, followed by a mask, and then participants reported both colors. At brief presentation times performance was near chance. As time increased there was a reliable advantage for high probability color pairs over low probability color pairs (~15% accuracy difference at 67ms, p<.05). This difference cannot be explained by differences in storage capacity for high and low probability pairs, because only 2 colors had to be remembered, and there was no difference between conditions at the longest presentation times.

Such an encoding-time advantage for high-probability color pairs suggests that participants may actually perceive high probability color pairs more rapidly, and that the compression of learned regularities can influence low levels of perceptual processing.

Rhee, G., Konkle, T., Brady, T. F., & Alvarez, G. A. (2011). Learning statistical regularities can speed the encoding of information into working memory. Poster to be presented at the annual meeting of the Vision Sciences Society, May 6-12, Naples, FL.