Doctors at University College London say that some people can “see” colours in response to people they know. Their report, in the Cognitive Neuropsychology journal, calls the condition emotion-colour synaesthesia.

Synaesthesia is a condition where crossed wires in the brain mean people can taste colours, or see sound. The London researchers studied a woman, known as G.W., who could see certain colours in response to the names of people she knew. When they wrote these people’s names in the “wrong” colours she became confused.

This has led them to conclude that auras are not mystical power fields that people give off. The colours are entirely in the brain of the beholder. And we all know people who make us see red.

American psychologists have, meanwhile, discovered the mechanism behind another way in which the brain tricks us: false memories.

Northwestern University researchers asked people to look at some objects, and visualise vividly other objects. Over time they got confused about which they had seen, and which they had imagined.

The authors of the study in Psychological Science, say: “We think parts of the brain used to actually perceive an object and to visually imagine an object overlap. A vividly imagined event can leave a memory trace in the brain that is very similar to that of an experienced event.”

SPRAY-ON SLIM

THIS could be a punch on the nose for obesity. The drugs giant Merck has announced a multimillion-pound partnership with a company that last year began testing a nasal spray drug designed to make the stomach feel full faster.

The drug, Peptide YY 3-36 Nasal Spray (or PYY for short), is a synthetic version of a hormone that the intestines send through the blood to tell the brain that the body is full about 30 to 45 minutes after a person starts eating.

That mechanism kept our grain-eating ancestors from consuming too much but it doesn’t kick in fast enough for people eating lots of modern high-calorie, high-fat foods.

The compound could be given to obese people in an injection before meals but the makers worried that this would deter people.

So they have developed it into a nasal spray, which also allows the drug to reach the brain more quickly — about 20 minutes after the dose.

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