The following is an evaluation of the research questions, testable hypotheses, dependent and independent variables, and types of hypothesis in Grant and Gino (2010).
The research question was "how do gratitude expressions affect prosocial behavior through the mediating variables of self-efficacy and social value" (Grant & Gino, 2010, p. 946; Laureate Education, Inc., n.d.). Expressions of gratitude are the independent variables (what were manipulated and what is expected to cause the dependent variable). The mediator variables are self-efficacy and self-worth.
The inferential questions are: can the expression of gratitude be associated with self-efficacy; and can the expression of gratitude be associated with feelings of social value. Both questions seek to make an association between the independent and independent variables (Laureate Education, Inc., n.d.). The authors are consistent in their placement and use of the independent and the independent variables - they consistently refer to the effects of gratitude expressions on the dependent variables, which are social value and self-efficacy (both mediators of helping or prosocial behavior).
The first testable hypothesis, which builds on the research question, is "when beneficiaries express gratitude, helpers will feel greater self-efficacy, which will motivate them to engage in prosocial behavior" (Grant & Gino, 2010, p. 947). A null hypothesis would have been 'gratitude expressions do not affect self-efficacy.' However, in this study, the authors use a directional hypothesis that supposes that gratitude expressions provoke self-efficacy, which motivates helping behavior (Creswell, 2009). In this hypothesis, the dependent variable is self-efficacy and the independent variable is expressions of gratitude. This is a predictive hypothesis.
The second testable hypothesis, which also builds on the research question, is "when beneficiaries express gratitude, helpers feel socially valued, which motivates helpers' prosocial behavior" (Grant & Gino, 2010, p. 947). A null hypothesis might have been 'gratitude expressions do not affect prosocial behavior.' As with the first testable hypothesis, the authors use a directional hypothesis that expresses their belief that experiences of social value will affect helping behavior (Creswell, 2009). In this hypothesis, social value is the independent variable and expressions of gratitude is the dependent variable. This, too, is a predictive hypothesis.
Grant, A.M., & Gino, F. (2010). A little thanks goes a long way: Explaining why gratitude
expressions motivate prosocial behavior. Journal of Personality and Social Psychology, 98(6), 946-955. doi: 10.1037/a0017935
Creswell, J. (2009). Research design: Qualitative, quantitative, and mixed methods approaches (3rd ed.). Thousand Oaks, CA: Sage Publications.
Laureate Education, Inc. (n.d.) Research Questions and Hypotheses Checklist. [Handout] Baltimore: Author