Ninth Edition CoverGraziano & Raulin
Research Methods (9th edition)

Example of
Differential Research

Example #1

Nademin, E., Jobes, D. A., Pflanz, S. E., Jacoby, A. M., Ghahramanlou-Holloway, M., Campise, R., Joiner, T., Wagner, B. M., & Johnson, L. (2008). An investigation of interpersonal-psychological variables in Air Force suicides: A controlled-comparison study. Archives of Suicide Research, 12(4), 309–326.


This differential research tested whether a particular theory of the causes for suicide can be used to identify known cases of suicide and differentiate them from an active duty sample of Air Force personnel. The theory was used as basis for a series of measurements for the potential for suicide (the suicide scale.) The measures were then applied to a random sample of postmortem records of military suicide cases between 1996-2006 (the experimental or target group) and to a sample of current active duty Air Force personnel (the control or differential comparison group).  The results indicated that the suicide scale measures did reliably differentiate the two groups. The authors conclude that the measures may be valuable in the development of suicide-prediction measures for use in the military. They discuss their findings and implications for suicide prevention efforts in the U. S. military.

Example # 2

Vivanti, G., Nadig, A., Ozonoff, S., & Rogers, S. J. (2008). What do children with autism attend to during imitation tasks? Journal of Experimental Child Psychology, 101, 186-205. 


Children with autism show a general deficit in visual attention to social stimuli and in imitative ability. Specifically, they show difficulty in “precision” imitation of another person’s action. In this differential design study, the researchers compared a group of children with autism with a group (matched on age, gender ratio, language level, & IQ) of typically developing children.  They asked whether children with autism display more difficulty with visual attention when observing an action to be imitated and whether those attention deficits contribute to their difficulties imitating the observed action.

The two differential groups of children were compared on eye-tracking tasks. Each child watched a series of video presentations of a person demonstrating various actions, some with objects. The electronic tracking device monitored and recorded the participants’ eye-movements. After each presentation, the screen went blank and the child imitated the actions that had just been demonstrated. Data were recorded for both the visual attention (eye-tracking) tasks and the motor imitation tasks.

The results indicated that children with autism and the controls did not differ in the amount of time spent on attention to the action to be imitated. However, there were significant differences in attention paid to the face of the demonstrator. While both groups attended to the action demonstrated and to the demonstrator’s face, the autistic group paid far less attention to the face.

In their discussion, the authors note that most children pay attention to faces in social situations when the action is ambiguous. They do so to pick up cues from the other person’s facial expressions. Children with autism pay less attention to faces and therefore may miss out on important social cues. 

Example #3

Olson-Buchanan, J. B. (1996). Voicing discontent: What happens to the grievance filer after the grievance? Journal of Applied Psychology, 81, 52-63.


Research suggested that people who file grievances are punished by their managers with a lower performance ratings and a higher rate of being fired. The question evaluated in this study was whether the low performance ratings were a form of retaliation or an object indicator of lower performance by the people who filed the grievances. Two groups of participants were studied: Participants in one group filed a grievance and participants in the other group did not. The researcher found that the objective job performance was lower in the group that had filed grievances, thus challenging the notion that lower performance ratings necessarily reflect a retaliatory response by managers.

Example #4

MacFarland, W. L., & Morris, S. J. (1998). Are dysphoric individuals more suggestible or less suggestible than non-dysphoric individuals? Journal of Counseling Psychology, 45, 225-229.


College students scoring high (dysphoric group) and low (no-dysphoric group) on the Beck Depression Inventory were given the Gudjonsson Suggestibility Scale, Form 2. As hypothesized, dysphoric subjects were more likely than non-dysphoric subjects to be suggestible. The authors concluded that dysphoric subjects may be highly suggestible clients compared to other clients.

Example #5

Kline, J. P., Allen, J. J. B., & Schwartz, G. E. (1998). Is left frontal brain activation in defensiveness gender specific? Journal of Abnormal Psychology, 107, 149-153.


The authors investigated sex differences in the relationship between level of defensiveness and pattern of brain activation. Defensiveness was measured with a self-report inventory (the Eysenck Personality Questionnaire L Scale), and EEG was used to measure the pattern of brain activation. Curiously, increased defensiveness was associated with higher left frontal activation in women but higher right frontal activation in men.

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