Below is a set of two SPSS simple effects tests using the split file function. Note that this only looks at two of the simple effects tests rather than all four. The first simple effects looks at the Mostly Empty condition while the second simple effects test looks at the Mostly Full condition.

Dependent Variable: How willing are participants to donate? Theater Crowd Size (1 = Mostly Empty, 2 = Mostly Theater Location (1 = Full) Live, 2 = Imagined) Mean Std. Deviation N Mostly Empty Live 6.90 553 20 Imagined 6.80 616 20 Total 6.85 580 40 Mostly Full Live 6.60 940 20 Imagined 6.10 1.165 20 Total 6.35 1.075 40 Tests of Between-Subjects Effects Dependent Variable: How willing are participants to donate? Theater Crowd Size (1 = Mostly Empty, 2 = Mostly Type Ill Sum Full) Source of Squares df Mean Square F Sig Mostly Empty Corrected Model 100 1 100 292 592 Intercept 1876.900 1876.900 5486.323 .000 Location 100 1 100 292 .592 Error 13.000 38 .342 Total 1890.000 40 Corrected Total 13.100 39 Mostly Full Corrected Model 2.500 1 2.500 2.230 144 Intercept 1612.900 1612.900 1438.737 000 Location 2.500 2.500 2.230 144 Error 42.600 38 1.121 Total 1658.000 40 Corrected Total 45.100 39