Phase locking to the video refresh for all seven observers
| Control | Luminance (stationary) | Luminance (modulated) | Drifting grating | Checkerboard (stationary) | Checkerboard (modulated) | |
|---|---|---|---|---|---|---|
| 57 Hz | 0 | 4 | 4 | 4 | 7 | 7 |
| 72 Hz | 0 | 1 | 1 | 3 | 2 | 5 |
| 90 Hz | 0 | 0 | 0 | 0 | 0 | 0 |
The numbers are the count of observers (of 7) who had statistically significant phase locking for each stimulus at each of the three CRT refresh frequencies. No subject had significant entrainment to a control stimulus, and the high-contrast checkerboards most often elicited entrainment. Results were similar regardless of whether a stimulus was stationary or temporally modulated.