The dynamic events that capture visual attention: A reply to Abrams and Christ (2005).

We recently demonstrated that, contrary to previous findings, some types of irrelevant motion are capable of capturing our attention (Franconeri & Simons, 2003). Strikingly, whereas sitmulated looming (a dynamic increase in object size) captured attention, simulated receding (a decrease in object size) did not. Abrams and Christ (2003, 2005) have provided a different interpretation of this evidence, arguing that in each case attention was captured by the onset of motion rather than by motion per se. They argued that the only published finding inconsistent with their motion onset account is our evidence that simulated receding motion failed to capture attention. Abrams and Christ (2005) presented a receding object stereoscopically and found that it did capture attention, leading them to conclude that the motion onset account explains existing data more parsimoniously than our account does. Our reply has three parts. First, we argue that evidence of capture by receding motion is interesting but irrelevant to the debate over whether capture by motion requires a motion onset. Second, we show that the original empirical evidence in support of the motion onset claim (Abrams & Christ, 2003) put the motion-only condition at a critical disadvantage. We present a new experiment that demonstrates strong capture by motion in the absence of a motion onset, showing that motion onsets are not necessary for attention capture by dynamic events. Finally, we outline what is known about the set of dynamic events that capture attention.