What types of extraneous variables should the researchers beconcerned about in this study?

Purpose of the Study. The researchers examinedpreferences for beer under conditions that varied in terms of wheninformation about an ingredient of one of the beers was given:before tasting, after tasting but before preferences wereindicated, and never (no information was given to one group aboutthe ingredients). The ingredient given is one that most peoplethink should make the beer taste worse. The research question waswhether the timing of the ingredient information would affect thepreference for the beer by influencing one’s expectation of tasteof the beer. Preference for the beer with the undesired ingredientshould be lower in any condition where the information influencesthe preference.

Method of the Study. Pub patrons inMassachusetts were asked to participate in a taste test of twotypes of beer labeled “regular beer” and “MIT brew.” The “MIT brew”contained a few drops of balsamic vinegar (the vinegar apparentlychanged the flavor of the beer very little). Participants wererandomly assigned to one of the three groups that differedaccording to when information was given: blind group (noinformation given), before-tasting group (information given beforetasting), and after-tasting group (information given after tastingbut before preference was indicated). All participants were given asmall sample of each beer to taste. They were asked to indicatewhich of the two beers they preferred.

Results of the Study. In the blind condition,the “MIT brew” was preferred more often (about 60% of the group)than the before condition (only about 30% of the group), indicatingthat ingredient information had an effect before tasting. However,the “MIT brew” was also preferred more often in the after condition(just over 50% of the group) than in the before condition and wasnot preferred less often than the blind condition, indicating thatwhen ingredient information is given after tasting, it does notaffect preference. Figure B.1 presents the means of the threegroups.

Conclusions of the Study. The researchersconcluded that the timing of information about a beer-drinkingexperience affects preference for the beer. Their results indicatedthat when information about the beer ingredient was given beforethe participants tasted the beer, it affected their tastingexperience (and their preferences), but when information was givenafter the participants tasted the beer, it did not affect theirexperience or their preference. More generally, this study showedthat our expectations of our perceptual experiences affect how wejudge those experiences.

SOURCE: Results from Lee, Frederick, and Ariely’s (2006)study.