From what i think i understand about the way the eye works, we have cells which can identify either red, blue or green light, which i guess corresponds to a certain wavelength (475nm, 510nm, 650nm), yet yellow light, for example, has a wavelength of 570nm. Is this picked up only partially by red and green receptors? If this is the case, technology using 3 colours of pixels in screens must be perfectly adapted to human eyes, yet a new type of television has been released with a yellow pixel as well. Would that offer any advantage to colour perception, or is it just smoke and mirrors?

Why do we perceive the sun as yellow? I understand that its colour arises from the mixture of wavelengths in sunlight. But as sunlight has been the main source of illumination throughout evolution - the background light to everything on the planet up to the invention of electric light - it gives us our default colour for everything. So why don't we consider it to be the neutral colour - in other words, white?

Perry Bebbington, Kimberley, Nottinghamshire, UK

There have been numerous occasions when I have consciously noted that a song sounds slower or faster than on a different occasion. When I try and keep pace with the rhythm in my head I find that I am still in time but my brain is telling me that both the tempo of the song and in my mind is different to a previous experience of the song. The difference is very small but noticeabe. Is it possible that my mind is perceiving time at a faster or slower pace?

Many modern cars use high brightness LEDs for their rear lights. They tend to be rapidly switched on and off for 'normal intensity' and fully on for 'high intensity' when the brakes are also applied. When driving behind these cars I find the LED lights very distracting - whenever I move my eyes from one spot to another the lights appear to leave a trail of very bright dots caused by their rapid switching. Normal incandescent bulbs do not look like this, nor do the LED car lights when they at full intensity. Domestic items with LED displays also tend to do the same thing (I noticed it on a washing machine today). I also see it to a lesser extent with fluorescent lights.

My daughter also sees the flickering car lights when moving her eyes, but my son does not, and neither do other people I've asked. I understand why LEDs are rapidly switched in this way, and why they appear as a string of dots when I move my eyes - my question is why do some people apparently not see the effect? Is our perception somehow different? I have read reports that the brain 'switches off' visual processing when the eyes are flicked from one point to another - could this 'switching off' vary from one person to another?