Question 1: Research Questions and purpose
This research was purposely designed to investigate the effects associated with racial stressors on the cardio-vascular responses among both the African Americans and the Caucasian men. It was also tailored to capture the role played by hostility in exacerbating cardio-vascular responses. It was set to test the previous studies that had asserted that anger-provoking and racist stimuli elicited greater increases n the blood pressure than neutral stimuli in both the African Americans as well as their Caucasian counterparts.
Some of the research questions this study was responding to include:
- What is the role of hostility in exacerbating cardiovascular responses?
- Do race stressors increase cardiovascular responses than other anger provoking stressors?
- Is there a relationship between ethnicity and cardiovascular responses to hostility?
Question 2: Research design
This study used experimental research design because of the following reasons;
It involves manipulation of the independent variable. In the context of this study, the independent variables were the various stressors, which are believed to be the causes of the cardiovascular responses exhibited by individuals. For instance, the stressors are changed from neutral to anger provoking and finally to those that had racial hostility (Mitchell & Jolley, 2001; Pashler, 2002).
There was some control of the extraneous variables in the experiment like the age of the participants, which ranged from 18-25; health, physical fitness, and family history among other extraneous variables. There was some degree of control as participants in both the African Americans and the Caucasians were exposed to conditions with a similar impact and had almost the same mean age and were all males (Mitchell & Jolley, 2001).
It is also prudent to mention that some parts of the study did not yield significant results because some of the factors, which are critical, were not catered for. For instance, the results from the speech part of the study did not yield the desired results because participants were allowed to express their opinions hence their emotions could not be manipulated or probably, as it is claimed in the study, some of them had watched the movies from which those clips were sourced hence had already dealt with the emotions that come with such a stimuli. This can be taken as a confounding factor and all these issues are majorly concerned with experimental research as opposed to any other (Mitchell & Jolley, 2001).
Question 3: Validity and Reliability of instruments
It is true to say that the instruments used in this study are reliable and valid. Even though not all the instruments yielded desired results but there is an explanation as to why this happened. The study involved two groups; the Caucasians and the African Americans. The results obtained in both groups were consistent, which gives more credit to the instruments used. For instance, the cardiovascular responses to the various stressors were similar, based on the mean and the standard deviation values obtained. In addition, there is not at any point during the study that the results obtained conflicted. This makes it very clear that if at all there was an error, then its origin was elsewhere outside the research instruments used (Kaplan & Saccuzzo, 2010).
Question 4: ANCOVA results
ANCOVAs were performed for the different sets of data to ensure there were no significant differences between the groups. By so doing, it ensured that the results obtained were not influenced by other factors emanating from the differences between the groups. For the physiological responses to the various stressors, a series of 2 (ethnicity) × 2 (order) × (Film condition) ANCOVAs were done to test for the possible order effects on the SBP, DBP, and HR reactivity, to control the body mass and the baseline SBP, DBP, and HR respectively. Because there were no significant differences, the data was collapsed across the two orders for all the analyses that followed thereafter.
For the film condition, mixed factorial ANCOVA with BMI whereas BP or HR was used as covariate. In the case of BP as covariate, planned comparisons showed a significantly higher DBP reactivity in response to the racist clip. The same results were obtained for the anger provoking film clip but no significant difference was noted between anger provoking film clip and the racist clip. On the other hand, analyses using HR reactivity showed some significant and major effects of ethnicity whereby Caucasian showed a greater response to HR than the African Americans. This was the only significant difference found using HR.
In the case of the speech task, a multi-factorial ANCOVA was done while controlling for BMI, the number of words spoken and the baseline levels of both the SBP, DBP, or HR. in this case, there was no significant difference noted for all the tests.
For recovery period, BMI and baseline SBP, DBP, or HR were used as covariates. There not so many differences except for the main hostility effect where high hostile participants exhibited a greater recovery SBP and DBP response as compared to the low-hostile participants. It is also notable that African American showed greater elevations in DBP as they recovered after the racist film in comparison to the neutral film while at the same time DBP changes were higher during recovery after the racist film clip in comparison to the anger provoking film. Contrastingly, for the Caucasian participants, it is notable that there were no significant differences at all levels during the recovery time. Furthermore, HR reactivity did not have any significant differences (Howell, 2009).
Question 5: Results
Question 6: Significant results
ANOVA analysis of the results showed that participants in both the anger provoking and the racist film clips showed higher levels of anger than in the neutral film clip.
Caucasian participants showed the highest anger, followed by the racist films whereas the neutral film had the least level of anger. On the other hand, the African American participants showed that there was no significant between the anger in both the racist and anger provoking clips although all of them had higher levels of anger than in the neutral film. It is also worth noting that Caucasian participants found it more difficult to identify with the characters in the film than did the African Americans.
Question 7: Threats to internal and/or external validity
Given that the two groups were subjected to different film clips, even though the rating were almost the same, there is a greater threat that the results obtained could not be compared will because of these clips cannot in any way evoke similar reactions. In addition, all the tasks were carried out on the same day after short time intervals; there are higher chances that earlier experiences had some influence on the results in the later tasks. For instance, after being subjected to an anger-provoking clip, there is a higher likelihood that this feeling influenced the participants’ response to the racist film clip and the interim speech tasks. In addition, there are chances that participants got bored with time and this boredom affected how they responded to the various stimuli in the course of the study. Therefore, when these factors are combined, they pose questions on both the internal and external validity of the results. Furthermore, some of the tasks like the speech task did not yield better results, indicating a possibility of errors or other extraneous variables not catered for when conducting the study (Pashler, 2002).
Question 8: Recommended redesign
Based on the above threats to the validity of the results of the study, I would propose the following changes to the design.
The same procedure and approach would be used as the one used in this study. However, the participants would only be given an overview of what the study is about without disclosing to them the exact variables to be measured. In addition, the various tasks would be performed on different days to avoid the influence of one stimulus on the next one. The film clips will also be similar in everything except that characters will be changed to bring out the aspect of ethnicity. In this regard, t is preferred that a special enactment of a scene is done specifically for the study so that none of the participants familiarizes with it. By so doing, it will help eliminate some of the extraneous variables that affected this study as depicted in the results obtained.
Howell, D. C. (2009) Statistical methods for psychology (7th Ed.). Belmont: Cengage Wadsworth
Kaplan, R.M., & Saccuzzo, D.P. (2010). Psychological Testing: Principles, Applications, and Issues. (8th Ed.). Belmont, CA: Wadsworth, Cengage Learning
Mitchell, M. & Jolley, J. (2001). Research Design Explained (4th Ed) New York: Harcourt
Pashler, H. (2002). Stevens' Handbook of Experimental Psychology. (Ed.).New York: Wiley