Do you dream in black and white or in full glorious technicolour? Your answer could well depend on what sort of TV you watched as a child, because a new study has provided more support for the theory that people who only watched black and white TV and movies as children also dream in black and white instead of colour.
Studies throughout the 20th century suggested that when colour TV and film arrived, dreams too suddenly shifted from black and white to colour.
But the age old problem with dream studies is how accurately people report what it was they dreamed. We all know how easy it is to forget about what happened in our dreams.
In earlier studies, from times when TV was still in black and white, researchers asked subjects to complete questionnaires in the middle of the day to record their dreams, so they could have simply been forgetting about their colourful dreams. And then later studies used a different technique of asking people to record their dreams in a diary as soon as they woke up, which should be more accurate.
Now Eva Murzyn from the University of Dundee here in the UK has revisited these earlier studies and repeated the two different methods to verify the link between what we watch and what we dream.
She recruited 60 people to her study, half of them under 25 and half over 55, and gave them a questionnaire to find out what sort of TV they watched as a child and what their dreams were like now. They were also asked to keep dream diaries every morning.
She found was there was in fact no great difference between the two different methods, so the earlier studies probably could well be comparable.
She also found that exposure to black and white TV could still be influencing the dreams of people over 40 years later. In the younger age group less than 5% of people dreamed in black and white and of the older folk who had access to colour TV during their childhood, around 7% dream now in black and white. That's low compared to 25% of the older age group who had not seen a colour TV as a child, and who still dream in black and white.
So, what could be causing these differences in dreaming? There are theories that our dreams are developing up until the age of around 12, which could suggest that exposure to moving images, especially films that we get emotionally involved in, are likely to influence our dreams in a way that stays with us later in life.
This latest study still can't distinguish between two possible explanations for the findings. It could be that exposure to black and white movies as a child really could have a lasting effect on dreams, or it could be instead the widespread cultural beliefs of how we dream that is in fact getting in the way of people correctly remembering their dreams. If you believe that you must be dreaming in black and white, like everyone else apparently is, then that could be enough to convince yourself that you are.
The only way of finding out for sure would be experiments with people who can control their dreams - known as lucid dreaming - can signal while they are dreaming, whether they are seeing in colour or black and white.
But what about people who've never watched TV?