Psychological research has shown that simply seeing a smile or a frown can activate the muscles in the face that make that expression whether we are aware of it or not. Researchers from the universities of Amsterdam and Utrecht decided to try and see whether words would have the same effect. They asked participants to read a series of verbs and adjectives on a monitor while they measured activity in muscles responsible for smiling and frowning. They found that verbs produced activity in the relevant muscles - e.g. 'smile' produced activity in the 'smile' muscles - but that this effect was much weaker for adjectives such as 'funny' or 'frustrating.' In another experiment the participants watched a series of cartoons and were subliminally shown 'smiling' or 'frowning' words after each one. Those participants who saw 'smiling' words after being shown the cartoons rated them as funnier than those who saw 'frowning' ones. However, in those participants who were prevented from smiling (by being made to hold a pen in their teeth) being shown the 'smiling' word after the cartoon had no effect on how funny they felt the cartoon to be.
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