Four Perspectives on . . .
14
The factor structure of the scales was evaluated in our data using the SPSS 7.5 principle
axis routine. Because two factors were expected, we constrained the solution accordingly, then
requested varimax rotation to clarify the loadings. Although some items exhibited substantial
cross loadings, all of them showed their highest association with the intended factor. In deference
to Carver and White’s (1994) larger sample (N = 732), we constructed the two scales as per their
instructions. In our data, alpha reliability was .78 for the BIS and .82 for the BAS. The items
were summed within scales, then divided by the number of items, thereby returning the variables
to a 1 to 4 metric. Descriptive statistics are given in Table 1.
...TABLE 1 ABOUT HERE...
Fear. To assess emotional state, participants responded to three items -- fearful, afraid,
and scared – using a 5-point scale anchored at 0 with “None of this feeling” and at 4 with “A
great deal of this feeling.” The items were administered three times, which permitted
construction of four indices of fear (
∀
= .83, .94, and .91 at times 1, 2, and 3 respectively). The
time 1 measure assessed premessage fear, while the time 2 measure was considered an indication
of velocity. Fear acceleration was estimated by comparing time 1 with time 2 (t2 - t1). The
difference between time 2 and time 3 fear scores constituted the deceleration index (t2 - t3). For
clarity of interpretation in later analyses, it is important for readers to note that the acceleration
and deceleration measures were constructed such that positive values indicated more of the
property under study (i.e., more acceleration and more deceleration).
Likelihood of Obtaining a Vaccination. Both before and after reading the message,
participants were asked the following question: “All things considered, how likely is it that you
will get a flu vaccination from University Health Services during the 1999-2000 school year?"
Convention