A sedative drug that interferes with memory also has the contrasting effect of enhancing intuition – the ability to use one’s ‘gut feelings’ – according to researchers at the Universities of Arizona and Colorado.
Michael Frank and colleagues tested the ability of 23 participants to learn the relative value of different abstract symbols. The participants learned through trial and error which of two symbols was the more valuable, one pair at a time. Later on, they were tested on their ability to recall the outcome of many of these specific pairings, and also on their ability to work out the more valuable of two symbols not previously compared.
After taking the tranquiliser Midazolam, participants became worse at remembering the outcome of previously encountered pairings, but they actually became better at solving the outcome of novel pairs. Novel pairings can be solved either by logically working through one’s memory of the previous pairings or by using one’s intuitive sense of which symbol is the more valuable based on its overall performance during the learning phase. The researchers believe Midazolam interfered with explicit memory for previous pairs, but enhanced participants’ ability to use their gut feeling to solve novel pairs.
The researchers say this supports the idea that learning can occur via two distinct systems – an explicit, hippocampus-based system, and an implicit, intuitive system, more dependent on the brain’s reward pathways. And they believe that by knocking out hippocampus-based explicit memory, Midazolam actually enhances memory based on intuition.
“We suggest that the brain areas associated with implicit reward-association decisions are dissociable from those supporting the explicit forms of decision making”, the researchers concluded. “Our findings suggest that it may be useful to rely on intuition to guide decisions, particularly when explicit memory fails”.
Frank, M.J., O’Reilly, R.C. & Curran, T. (2006). When memory fails, intuition reigns. Midazolam enhances implicit inference in humans. Psychological Science, 17, 700-707.