Is “Learning by Osmosis” Real?

Beginning this academic year, the University of South Dakota Honors Program has sponsored a series of FLASH lectures.  This series brings professors from multiple disciplines to deliver “lectures” lasting approximately one to four minutes in a high-traffic area in the student center during the noon hour.  Ideally the lecture topics have some novelty or a unique perspective, may be related to a current event or issue, and may be a little controversial or thought-provoking – something that could get people talking.  Previous FLASH Lectures are available on the Honors Program YouTube channel:

booksleep2I am lined up to present a FLASH lecture on March 2, 2015 and I have chosen to talk about whether or not “Learning by Osmosis” is real.

As a membrane transport physiologist who teaches osmosis, I certainly know that learning by osmosis isn’t a thing (  The true definition of osmosis according to Silverthorn’s Human Physiology: An Integrative Approach is “the movement of water across a membrane in response to a solute concentration gradient” which can be determined by calculating the osmotic pressure gradient across a selectively permeable barrier using van’t Hoff’s Law (Dp = (sDnRT)/V = sDCRT).  Students may hope that sleeping with their textbook under their fluffy pillow or recording a lecture and listening to it in their sleep would allow them to wake up knowing everything about the content.  While educational scholars know that this is not the case, as active learning to construct new meanings on foundational knowledge is how people learn best, evidence has shown that some learning can occur during sleep.

Rasch and colleagues facilitated memory consolidation during sleep by presenting an odor that had been used as context during prior learning.  Their research showed that the re-exposure to the odor during slow wave sleep (delta waves or non-REM sleep) improved the retention of hippocampus-dependent declarative memories but not hippocampus-independent procedural memories.  The evidence implies that odor-induced reactivations of memories in humans during sleep can boost the consolidation of declarative memories related to hippocampal activity during slow wave sleep.

Subsequently, Rudoy and colleagues taught subjects to associate an image of an object on a computer screen paired with a characteristic sound before taking a nap.  White noise was then used during most of the nap; however when the subjects went into non-REM sleep, the sounds associated with half of the objects were presented again.  After waking, the subjects were asked to reposition the objects on the computer screen in their original positions.  Object placements were more accurate for the objects that were cued by their sounds during the nap.  Thus, information presented during sleep can influence subsequent retrieval during waking.

Wamsley and colleagues extended this research by studying the consolidation of a virtual navigation learning task through a maze by dreaming about it during post-training non-REM sleep in an afternoon nap.  The subjects who reported dreaming about the task had experienced greater difficulty in learning the maze, and continued to process the information during their nap leading to improvement on the retest five hours after the initial training.  Thus, dreaming about a learning task facilitated retrieval of the learning on a subsequent retest.

Finally, Antony and colleagues showed that information acquired during waking could be reactivated during sleep to promote memory stabilization.  They had subjects learn two melodies by moving visual symbols and then presented one of the melodies to the subject during slow wave sleep with a retest ten minutes after awakening from an approximately 90 minute sleep period.  Cued memory reactivation during sleep enhanced this type of skill learning as verified by electrophysiological signs of memory processing during sleep.  The auditory stimulation used in this study did not disrupt sleep but did facilitate memory consolidation.  The authors speculate that using suitable sleep cues may improve learning for a number of musical, athletic, linguistic, and other types of skills and question whether sleep cues can have detrimental effects on sleep quality.

Thus while it has been shown that consolidation of hippocampus-dependent forms of memory are enhanced by non-REM sleep, certain skills can also be learned during undisrupted sleep as cues are used for the initial training session and reactivated during the sleep period.  Thus, certain kinds of learning have been enhanced by exposure to the tasks while sleeping.  “Learning by osmosis” may be real!

  1. Anderson, Skylar. Learning by Osmosis Isn’t a Thing.  StudyRight blog post (, 2014.
  2. Antony, James W., Eric W. Gobel, Justin K. O’Hare, Paul J. Reber, and Ken A. Paller.  Cued Memory Reactivation During Sleep Influences Skill Learning.  Nature Neuroscience 15 (8): 1114-1116, 2012.
  3. Rasch, Björn, Christian Büchel, Steffen Gais, and Jan Born. Odor Cues During Slow-Wave Sleep Prompt Declarative Memory Consolidation.  Science 315: 1426-1429, 2007.
  4. Rudoy, John D., Joel L. Voss, Carmen E. Westerberg, and Ken A. Paller. Strengthening Individual Memories by Reactivating Them During Sleep.  Science 326: 1079, 2009.
  5. Wamsley, Erin J., Matthew Tucker, Jessica D. Payne, Joseph A. Benavides, and Robert Stickgold. Dreaming of a Learning Task Is Associated with Enhanced Sleep-Dependent Memory Consolidation.  Current Biology 20:850-855, 2010.





Barb Goodman received her PhD in Physiology from the University of Minnesota and is currently a Professor in the Basic Biomedical Sciences Department of the Sanford School of Medicine at the University of South Dakota. Her research focuses on improving student learning through innovative and active pedagogy.


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