Brad Bushman and colleagues were interested in studying an emotional state with a new name: “hangry.” This is a state when you are hungry, and more likely to get angry.
According to Bushman, when the brain is depleted of glucose, we have more trouble controlling difficult emotions such as anger. To test this, Bushman and his colleagues conducted a three week study. They followed about 200 married couples on a daily basis. Each night, the couples’ glucose levels were recorded, and they were given the opportunity to indicate their anger toward their spouse at that moment by sticking up to 51 pins into a voodoo doll representing their spouse:
The researchers found that the lower the blood sugar levels, the more pins were pushed into the doll. In fact, people with the lowest scores pushed in twice as many pins as those with the highest blood sugar levels, the researchers said.
Is the study described above correlational, simple experiment, or factorial experiment? How did you determine this?
Consider the following criticism of Bushman’s study:
Chris Beedie, who teaches psychology at the Aberystwyth University in the United Kingdom, said he thought the study’s method was flawed ….The better way to test Bushman’s concept is to give people high glucose on some occasions and then give those same people low glucose on other occasions, and see if that makes a difference in actual acts of aggression, he said.
a. Beedie is clearly describing an experiment. What would be the independent and dependent variables in Dr. Beedie’s proposed study?
b. Why is Dr. Beedie’s study design better than the Bushman’s study design? Explain at least one benefit of Dr. Beedie’s design addressing concepts we’ve discussed in class ?
c. From the two categories of experimental design we have discussed, what type of design is Dr. Beedie proposing? How did you determine this?
In “Study: Video Games Don’t Cause Psychological Harm in Children” researchers examined how video games affect childhood development:
Questions about this study:
1. Consider the type of claim this article reports.
a. What kind of claim (i.e., frequency, association, or causal) does the headline of the story suggest this study was?
b. Do the details of the study agree with the headline? What kind of claim is this study making? How do you know?
c. Was the study a simple-poll, bivariate correlation, multivariate correlation, or an experiment? How do you know?
2. Consider the measurements in this study relevant to the headline.
a. What are the key variable(s) of interest in this study?
b. How were these variable(s) in this study operationalized?
3. Considering the sample for the study.
a. Who and how large was the sample for this study?
b. The authors describe from where their sample came and who they are generalizing to. Using this information, what could you infer about the sampling technique they might have used to gather their study subjects (hint: Chapter 7)?
c. Does their study seem to have strong or weak statistical validity? Why?
4. The study measured a few other variables as well. Consider this excerpt:
After controlling for the fact that certain types of kids were more likely to play more hours of video games, such as older children, boys, and children from two-parent, well-educated families, the researchers found no association between video game playing and mental health problems. (Before the adjustment, the raw data showed that the kids who played more, were psychologically healthier.)
They mention a positive correlation before adjusting for these other variables.
a. Based on this, what can you conclude about the true relationship between video game playing and mental health problems?
b. What would you call the observed association between video game playing and mental health before adjusting for other variables?
Researchers were interested in investigating how children with autism see and understand the world. Participants included children diagnosed with autism and typically developing children, who were all approximately the same age. All children were presented with several different stimuli on a large computer screen for up to one minute. The stimuli were both social (i.e., people’s faces) and nonsocial (inanimate objects). The percentage of time children spent looking at the two types of stimuli were recorded (ranging from zero to 100). The results are presented below:
1. Considering the variables in this study:
a. Identify all the variables in this study. State whether they are Independent or Dependent.
b. Identify whether each variable is categorical or quantitative.
2. Identify whether the variables were manipulated, selected, or measured.
3. This is a Factorial design.
a. What type of factorial design is this (independent groups, repeated measures, or mixed)? Explain how you reached your answer.
b. What kind of design is this (put your answer in the ___ x ___ form)?
3. Given your responses in question 2, at least how many participants will need to be recruited if the researchers want to have 30 observations per cell?
4. The researchers calculated that for a result to be statistically significant the difference seen between comparison groups should be greater than 15% points. Given this information…
a. Describe whether or not there is a main effect for each Independent variable you identified. You must also interpret these findings.
b. Are there any interactions in the study? Interpret these findings.