15. Discuss the following hypothetical pieces of research and point out the problems with the research design which prevent you from drawing the stated conclusions. In addition, suggest at least two factors other than the one mentioned in the conclusion for each study that might have produced the results. There may be more than one way to view each situation.
a. To test the effects of marijuana on driving performance, some subjects were asked to smoke one marijuana cigarette while other subjects were asked to smoke one tobacco cigarette before taking a test of driving ability. The marijuana group did more poorly on the test, and the researcher concluded that marijuana impairs driving performance.
b. Children who watch a great deal of violent television programming are themselves more aggressive and violent in their play with other children than are children who do not watch so much violent programming. Therefore, watching violent programming leads to aggressive social behavior.
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a. The research design in this study is flawed because it does not control for confounding variables that may have influenced the results. The conclusion that marijuana impairs driving performance cannot be definitively drawn due to the following problems:
1. Sample Bias: The study does not mention whether the subjects were regular marijuana users or had previous experience with marijuana. If the subjects in the marijuana group were regular users, their performance might have been affected by tolerance to the drug, which could skew the results. Similarly, if the subjects in the tobacco group were non-smokers, the tobacco cigarette could have had a more significant impact on their driving performance.
2. Lack of Random Assignment: The study does not state whether the assignment of subjects to smoking conditions (marijuana or tobacco) was random. Without random assignment, there may be confounding variables that influence the driving performance of different groups, such as previous driving experience or state of mind.
Alternative factors that might have influenced the results:
1. Expectancy Effect: The subjects' beliefs about the effects of marijuana on driving performance could have influenced their actual performance. If the subjects thought that marijuana impairs driving, they might have performed worse due to a self-fulfilling prophecy.
2. Differences in Inhalation Technique: If the subjects were inexperienced in smoking marijuana, they might not have inhaled properly, leading to a weaker effect. In contrast, the tobacco group might have had more experience smoking and therefore inhaled more effectively, resulting in different levels of impairment.
b. The research design in this study suffers from potential confounding variables and does not establish a causal relationship between watching violent programming and aggressive social behavior. The conclusion that watching violent programming leads to aggressive behavior cannot be definitively drawn due to the following problems:
1. Third Variable Problem: The study does not account for other potential factors that could influence children's behavior. For example, children who watch more violent programming may have parents who are less attentive or have less involved parenting styles. The parents' parenting style could be the actual factor leading to increased aggression, rather than the television programming itself.
2. Reverse Causality: The study did not establish the temporal order of events. It is possible that children who are already aggressive and violent are more inclined to choose violent programming. In this case, the aggressive behavior may precede and influence the choice of television content, rather than the content causing the aggression.
Alternative factors that might have influenced the results:
1. Peer Influence: Children who watch violent programming may be more likely to have friends who also engage in aggressive play. The influence of peers who exhibit aggressive behavior might lead to the observed correlation, rather than direct causation from television.
2. Media literacy and parental guidance: Children who lack media literacy skills or parental guidance may interpret violent programming more aggressively, resulting in aggressive play. Children with better media literacy and parental guidance might interpret such content differently, leading to different social behavior outcomes.