[thedoc (OP)]

We face our fears and head into the dark to find out when it all began...
Read a transcript of the interview by clicking here

or [chapter podcast=1001501 track=16.10.25/Naked_Scientists_Show_16.10.25_1005850.mp3] Listen to it now[/chapter] or [download as MP3]

[thedoc (OP)]

Read this interview by clicking here [chapter podcast=1001501 track=16.10.25/Naked_Scientists_Show_16.10.25_1005872.mp3] or Listen to it now[/chapter] or [download as MP3]

[alancalverd]

We (or most of us) receive about 99% of our information from our eyes, so it's not surprising that we get a little upset when that disappears. However although the video bandwidth is enormous, most of it is redundant: the exact colour of a leaf, or the number of leaves on a tree, can have an aesthetic impact but really isn't a matter of life and death, and even if it were, the decision could wait until morning.

The test is whether blind people are afraid of the dark, and AFAIK the answer is a rational caution in moving around with no middle- or long-distance cues at any time, but anything within earshot or arm's length is obviously no more of a problem, therefore no more an object of fear, at night than it is in daylight. In fact, knowing that your predators are unsighted gives you an advantage on your own territory. 

The "bandwidth" consideration is interesting when we consider driving, and more particularly flying, at night. Once you get past the initial unfamiliarity of moving at high speed with very few visual cues, you realise that having fewer distractions can actually improve your task accuracy if the important bits (road centerline, runway limits, other vehicles/aircraft) are reflective or properly lit. I, for one ,feel a lot more comfortable rushing around the country in the dark! 

[zx16]

Following on from the posts above, here is a question which I've sometimes thought about:

Suppose a blind person is living alone in their own house.  The person has adapted to their blindness, to the extent that they can manage everyday tasks, such as getting up, washing, moving about the house, preparing meals, and everything else, with competence.

When night comes (as perhaps announced by the radio, saying it's ten o'clock), does the person switch on the electric lights in their house, or do they carry on doing everything in the dark?

Logically, there's no reason at all why the person should switch on the lights at night.  But doesn't it seem slightly eerie to be walking around in the dark, and perhaps making a supper sandwich or a cup of cocoa in a pitch-black kitchen?

[alancalverd]

My blind friends switch the lights on at night so that friends and potential thieves know the house is occupied. They also say a flickering television adds realism but as they can't see the picture, they turn the sound off and listen to the radio!

[zx16]

Thanks - the point about switching on the lights at night to deter burglars hadn't occurred to me.  But it makes sense.

Actually it reminds me of a very vaguely-remembered story, or perhaps a movie, something about a blind person who had a burglar or some person with nefarious intent in the house. And the blind person had switched off all the lights, thereby neutralising the sighted burglar's advantage, until a refrigerator door got opened in the kitchen, and the fridge's interior light shone out.

Does that ring a bell with anyone, I wonder?

[chris]

Blindness is not an all or none situation. Some "blind" people can still discriminate light from dark, or can see but have very poor acuity vision. As such, turning the lights on can be helpful because it adds extra information in terms of light contrasts, sometimes colours etc, which can make life easier (in addition to the benefits mentioned above).