Literature on conditioned stimulus intensity effects is briefly reviewed and one experiment presented with human subjects and a video-game method. The intensity (Bright or Dim) or color (Red or Blue) of a cue that predicted the appearance of a spaceship was manipulated. Testing was conducted with either the alternate brightness or the alternate color. Responding to the cue was unaffected by its intensity in training. During testing, a downshift in brightness decreased responding while an upshift had no effect, suggesting an asymmetrical intensity gradient. Red tended to condition better than Blue in the first phase, but the same participants conditioned better in the second phase to Blue. The results are discussed with respect to prior demonstrations of intensity effects using within-subject designs and favor an explanation based on stimulus-sampling theory.