As a new generation of smartwatches enters the market, one common use is for displaying information such as notifications. While some content might warrant immediately interrupting a user, there is also information that might be important to display yet less urgent. It would be useful to show this content on the watch but not immediately draw the user's attention away from their primary task. In this paper, we investigate how fast three visual parameters draw a user's attention. In particular, we present data from a smartwatch user study where we examine the size, frequency, and color of a visual prompt and the associated impact on reaction time. We find statistically significant differences for size and frequency where smaller and slower result in the less immediate reactions. We also present reaction time distributions that a designer can use to tailor expected notification response times to match their content.