Minimum duration for presenting a visual stimulus on screen

Question

My experiment involves presenting simple visual stimuli briefly on screen (200 ms to 1000 ms). The stimuli would be simple enough (e.g. a circle and a line) but I want to use a range of durations to test out some hypotheses. I would like to know if there's a minimal time for human eyes to perceive simple visual stimuli, so I could say "the durations I've chosen for my experiment are safely above the minimal value suggested by 'so and so' in the psychophysics experiment.

I am sure many factors would have an impact on such a value, such as the participant's condition and how far the target is (in my case it's the distance between someone, sitting at their desk, and the computer screen), etc., but perhaps there are data and rules already established? If anyone knows of applicable guidelines or literature, I would really appreciate it.

(I've tried searching under "tachistoscopic presentation minimum time" but haven't discovered anything useful yet. Any other search term combo would also be helpful.)

Answer 1

In psychophysics, this is known as an absolute threshold. The absolute threshold will depend on a variety of factors such as brightness, size, etc.

It is also important to keep in mind that the time needed to detect a stimulus may be too short to cause some desired effect on the participant (e.g. a manipulation). For example, the time needed to detect a stimulus is necessarily shorter than the time needed to identify a stimulus. Though research on subliminal stimuli suggests stimuli can sometimes be presented below threshold and still achieve some manipulation. However, some of this research is controversial.

Often, researchers will choose a range of display times specifically in order to unravel the time course of some cognitive process. For instance, when displaying a cluster of dots, how long is needed in order to subitize them?

There is insufficient information in your question to give you an exact number, but I suggest looking at similar studies and see what sort of display times they use.

Answer 2

This depends on intensity but it is shorter at most intensities than your screen could possibly present a stimulus. Don't worry about it or cite references. It would be like citing a reference for why you don't need to worry about quantum effects when testing the best kind of screwdriver.