Birth Order of Volunteers under Varying Conditions of Recruitment Incentive

In two studies of volunteering, recruitment pressure was varied in an attempt to see if firstborns were more susceptible. In the first, two classes of junior college students were pressured by offering a reward to be given only if a large percentage of the class volunteered. Of 55 Ss 19 who responded by raising their hands were firstborns. In two control classes where no incentive was offered, 33 Ss, including 9 firstborns, raised their hands. In the second study, pressure, in the form of an appeal for volunteers, was manipulated with extra credit in a 2 × 2 design. Firstborns were not more likely to volunteer in either study. Extra credit resulted in a higher percentage of volunteers but did not affect firstborns differently from later borns. Arguments were presented against the generality of birth-order effects in volunteering studies.