It seems self-evident that one should not put a large box on the screen and then change its dominant color frequently (i.e. make it flash) because it's very hard to ignore and will irritate people, but I have not been able to find a definite Web-accessible resource to point at that argues for this statement. Can anyone suggest anything? A document arguing that one should not make anything on the screen flash for the same reasons would also be fine.

(This is not a request to write out an argument here, this is a request for an existing document that I can link to in something else I'm writing.)

  • I'm kind of curious why a well-written explanation here, from expert practitioners of the field, wouldn't be sufficient... – Alex Feinman Apr 27 '11 at 14:14
  • Because I asked the question. If I link from an article on my blog to an explanation I asked somebody to write, it looks like I'm astroturfing. – zwol Apr 27 '11 at 15:44
  • I think if you answered it it might look odd. But we're not in collusion with you. Anyway, you got some nice cites, so the point is moot... – Alex Feinman Apr 27 '11 at 15:52
  • flashing directs attention. That, in and of itself isn't necessarily annoying. What's annoying is if the attention is being focused on something that is not a direct benefit to the UX. – DA01 Apr 27 '11 at 21:24

The argument is that our peripheral vision is set up by evolution to pull our attention towards any sudden movement (such as the sabre toothed tiger which is just about to eat you). So your attention gets pulled towards moving / flashing things whether you like it or not.

If you google 'peripheral vision sabre toothed tigers' there's a fair amount around on this.

Susan Weinschenk also covers it in a blog post here:


  • I'm accepting this answer because it's the answer I'm going to use in the blog post, but all the other answers are also great. Thanks everyone! – zwol May 2 '11 at 22:40

The Web Content Accessibility Guidelines go over flashing and flickering content, but only as it applies to seizures, not general annoyance. http://www.w3.org/TR/WCAG20/#seizure

The UN accessibility guidelines go into more detail: http://www.un.org/webaccessibility/1_visual/15_nomoving.shtml

Section 508 guidelines say "It is best not to use products that have flashing or blinking elements" and go over accessible frequencies: http://www.uspto.gov/web/offices/cio/s508/02software.htm#standard_k


Couldn't find an actual research document on this, it seems to be taken as pretty much self-evident.

But along related lines:

  • "Scrolling text, marquees and constantly running animations" (Jakob Nielsen "Original Top Ten Mistakes in Web Design", 1996):

    Never include page elements that move incessantly. [...]

    Of course, <BLINK> is simply evil. Enough said.

  • Scrolling text and looping animations (Jakob Nielsen, "Top Ten Mistakes Revisited", 1999):

    It is as hard as ever to read scrolling text, but aggressive use of distracting animation now causes even more problems than in 1996: users have started equating such designs with advertising which they routinely ignore.

  • "Anything That Looks Like an Advertisement" (Jakob Nielsen "Top 10 Mistakes in Web Design", 2011):

    animation avoidance makes users ignore areas with blinking or flashing text or other aggressive animations

So the argument seems to have moved from "annoying" to "ineffective": The louder you yell at people, the busier they become looking elsewhere.


Here’s a couple scholarly studies showing animation causing user performance decrements:

Zhang, p (2000). The Effects of Animation on Information Seeking Performance on the World Wide Web: Securing Attention or Interfering with Primary Tasks? Journal of the Association of Information Sciences, 1(1) (March) Article No. 1.

Burke, M., Hornof, A., Nilsen, E., & Gorman N. (2005). High-Cost Banner Blindness: Ads Increase Perceived Workload, Hinder Visual Search, and Are Forgotten. ACM Transactions on Computer-Human Interaction (TOCHI), 12(4) (December).

Usability.gov's Research-Based Web Design & Usability Guidelines also has cites associated with Guideline 14.4 Use Video, Animation, and Audio Meaningfully in its chapter on Graphics, Images, and Multimedia.


This is probably not available on the web, but Colin Ware covers it in his awesome book "Information Visualization: Perception for Design." He writes:

When early man was outside a cave, intently chipping a lump of flint into a hand axe, or when early woman was gathering roots out on the grassland, awareness of emerging objects in the periphery of vision would have had clear survival value. Such a movement might have signalled an imminent attack. Of course, the evolutionary advantage goes back much further than this. Monitoring the periphery of vision for moving predators or prey would provide a survival advantage for most animals. Thus, the most effective reminder might be an object that moves into view, disappears, and then reappears every so often.

These kinds of constant visual changes are not just hard to ignore, they're impossible to ignore. Every human who was able to ignore them was eventually eaten by tigers.

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