Question

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

Purpose of the Study. The researchers examined preferences for beer under conditions that varied in terms of when information about an ingredient of one of the beers was given: before tasting, after tasting but before preferences were indicated, and never (no information was given to one group about the ingredients). The ingredient given is one that most people think should make the beer taste worse. The research question was whether the timing of the ingredient information would affect the preference for the beer by influencing one’s expectation of taste of the beer. Preference for the beer with the undesired ingredient should be lower in any condition where the information influences the preference.

Method of the Study. Pub patrons in Massachusetts were asked to participate in a taste test of two types of beer labeled “regular beer” and “MIT brew.” The “MIT brew” contained a few drops of balsamic vinegar (the vinegar apparently changed the flavor of the beer very little). Participants were randomly assigned to one of the three groups that differed according to when information was given: blind group (no information given), before-tasting group (information given before tasting), and after-tasting group (information given after tasting but before preference was indicated). All participants were given a small sample of each beer to taste. They were asked to indicate which 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), indicating that 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 was not preferred less often than the blind condition, indicating that when ingredient information is given after tasting, it does not affect preference. Figure B.1 presents the means of the three groups.

Conclusions of the Study. The researchers concluded that the timing of information about a beer-drinking experience affects preference for the beer. Their results indicated that when information about the beer ingredient was given before the participants tasted the beer, it affected their tasting experience (and their preferences), but when information was given after the participants tasted the beer, it did not affect their experience or their preference. More generally, this study showed that our expectations of our perceptual experiences affect how we judge those experiences.

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

Answer 1

Extraneous variables are the additional variables that can affect the realtionship between independent and deendent variables in a study. These are of 4 main types-

Situational variables - it would include the environmental factors affecting the behavior of a person. Here these might include the area, ambience and the noice etc but this would be the same for everyone hence it is not that much of a risk.

Personal variables- the individual differences in case of mood, likes, dislikes etc are the parts of this. Here the personal variables like mood, anxiety, likes etc will effect the study.

Experimenters variables- this is also called experimenters bias. The experimenter tends to be tilted towards a particular results and tries to conclude the study into that only. As a results he might observe things in line with it and ignore others or else try to manipulate things such that the hypothesis can be proved right. Here also this variable would be a major variable as it is studied by only one researcher.

Demans variables- every study gets affected by the interaction between the researcher and the respondent, researchers behavior, respondents situations as well as the interpretation of what will happen in the study after the purpose and research instructions are given. Here after knowing the ingredients of the beer most of the people would have interpreted it as to try the new beer now and check the difference.

Soecifically the extraneous variables will be the familiarity of people with the test as some people will know what to expect out if it, familiarity to the taste of vinegar as some people might have had it and would know that they will like it, familiarity with taste of beer as the ones who know its taste would be very choosy but there might be people whi havent had beer and will be having it for the first and this would make them choose any as they wont notice a difference.