Waving a bright spot at night will make your eyes look like a line. What is the phenomenon?

I think there is nothing wrong with your understanding, but you don't understand the point.

This phenomenon is indeed a positive afterimage, that is, the excitement of optic nerve cells caused by previous stimulation has not subsided, and the excitement behind it has begun again.

None of these people are wrong. This is indeed visual residue, or sensory memory, that is, the physical stimulation acting on the senses stops. Our sensory organs still have this kind of stimulation for a short time, and we really can't do without it.

Just explain it from another angle.

But the key to your question is "at night, it will be regarded as a line", so although all the above are true, the most correct explanation is to use the concept of "critical frequency of flash fusion". That is to say, if the flash frequency is greater than our critical frequency, we can't distinguish it, but if it is lower than the critical frequency of our human eyes, we can distinguish it.

For example, if the flashing frequency of fluorescent lamps is lower than our critical frequency, we can see the lights flashing.

In the daytime, when we look at the moving bright spot, we don't think it is a line, because it is really below our critical frequency, and we can distinguish it. However, at night, the critical frequency of human eye flash fusion will decrease, so the fluctuation highlights that would not have been fused will also be regarded as a line.

This critical frequency is related to many factors, such as fatigue and age.

Therefore, people who drive at night should not be too tired or too old, otherwise it will be very dangerous.