I've read several articles and opinion pieces lately about the effect of expectations on our experience of the world. First, there are several studies that have shown that when we know the price of a product, it affects the way we experience it. And I don't mean we get tricked into thinking that the more expensive product is better because of clever marketing or packaging--using brain-imaging technology, it has been shown that these products actually do produce a more intense result. One example I've come across more than once is the ice cream test, which shows that consumers equate ice cream in a round tub as being better tasting than ice cream in a square tub. We are willing to pay several dollars more for it, even if it's the exact same ice cream. Or the wine test, which shows that people who think they are drinking expensive wine (even if they are not), find the wine to be better-tasting and get more brain activity in the pleasure centers of the brain when they drink it, compared with drinking wine that they have been told is cheap (again, this holds true even when the cheap and expensive wines are switched, or when both wines are the same!). Another study showed that our expectations about pain work the same way. Subjects were told to put one hand in a bucket of hot water and hold it there for a specific amount of time. Subjects who were told that the water was very, very hot experienced more pain than subjects who were told it would only be a little bit hot. The subjects evaluated their pain levels verbally and their comments were mirrored by the brain activity scans. Of course, the water was kept at a steady, mildly hot temperature for all subjects.
As fun as it must be to trick research subjects into experiencing false pain, this is more than just an academic exercise. Generic and name-brand drugs have the exact same ingredients and ought to work exactly the same. But they don't. If you have more trust in the name brand, you will get a better result from it than you will from the generic. This isn't just happening in your head--okay, it is, but that doesn't mean the effects aren't real. Your expectations about the product actually affect the way your body reacts to it physically. Placebos work in a similar way. When Prozac was initially in trials, it was found to be very effective when compared with the sugar pill that was given to the control group. However, now that the public has been convinced of the efficacy of Prozac, there is less of a difference between the results from the control group and the results from participants actually on the drug. Because the study participants in both groups believe that they are getting the treatment and have an expectation that it will work, even those in the placebo group see improvement (though the placebo effect does drop off after several weeks in the study). Again, this is not just based on how much improvement subjects say they are getting; brain imaging show that all study participants are actually less depressed.
Neuroscientist and writer Jonah Leher puts it this way, "The human brain, research suggests, isn't built for objectivity. The brain doesn't passively take in perceptions. Rather, brain regions involved in developing expectations can systematically alter the activity of areas involved in sensation. The cortex is "cooking the books," adjusting its own inputs depending on what it expects. Although much of this research has been done by scientists interested in marketing and consumer decisions, the work has broad implications. People assume that they perceive reality as it is, that our senses accurately record the outside world. Yet the science suggests that, in important ways, people experience reality not as it is, but as they expect it to be."
http://www.boston.com/bostonglobe/ideas/articles/2008/02/24/grape_expectations/
http://scienceblogs.com/cortex/2008/02/prozac_and_placebos.php
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