Comparisons that did not meet the equal variance assumption were corrected by fractional adjustment of degrees of freedom. Classic eta squared (η2) effect size calculations were performed to gauge the amount of variance our manipulations accounted for in the dependent measures evaluated. Using Cohen’s standards, eta squared values above 0.0099, 0.058, and 0.1379 can be considered small, medium, and large effects, respectively (Cohen, 1998), although limitations of these stated criteria (e.g., overestimation of population association, dependence upon sample size) must be acknowledged (Levine and Hullett, 2002, Pierce et al., 2004). Eta squared was calculated by dividing SSFactor by SSCorrected Total. All other analyses were performed using SPSS statistical software (version 16.0; SPSS Incorporated, Chicago, IL, USA).
