What the scientists are saying…
The people with no “mind’s eye”
Most of us can easily picture anything from an apple to our loved ones’ faces, and can conjure up detailed images of certain moments in our lives, but for those with aphantasia, mental imagery is either weak or non-existent. The condition was only named in 2015, when Adam Zeman, a professor of cognitive and behavioural neurology at the University of Exeter, and his collaborators identified 21 people who had no ability to visualise things at all. Since then, they’ve heard of thousands more people with aphantasia and also its opposite, hyperphantasia, in which the mental imagery is so vivid, it seems almost real. And dozens of papers have been published on the subject. Typically, people who have aphantasia only find out in their teens or 20s, when they are amazed to discover that “the mind’s eye” is not a metaphor and that other people can picture things in their heads. Now, Zeman has reviewed all the studies, and concluded that 1% of people have extreme aphantasia: they can’t even picture their own children, for instance. And a further 2-6% have visual memories that are vague or dim. Zeman thinks that in people with aphantasia, the connections between different regions of the brain are disrupted, causing memories to be stored without images attached. However, some see images while dreaming, suggesting dreams involve a different brain process.
Good sleep is an elixir of youth
Several studies have shown that people who continue to feel youthful even as they age tend to live longer, healthier lives. Now, scientists have found that feeling youthful can be down to simply getting enough sleep. A team from the Karolinska Institutet in Stockholm surveyed 429 people aged 18 to 70 about how old they felt and how well they’d slept in the past month. This revealed that for every night of broken sleep, those who’d slept badly felt a few months older than they actually were, whereas those who’d slept soundly across the period felt almost six years younger than their actual age. In a second study, 186 volunteers were asked to restrict their sleep. After getting only four hours of sleep for two nights in a row, they reported feeling four-and-a-half years older than on nights when they’d clocked up an ample nine hours; that’s an average figure – some of the participants said they felt decades older. “If you want to feel young, the most important thing is to protect your sleep,” Dr Leonie Balter told The Guardian.
An unfair advantage in tennis
If your tennis partner keeps beating you, no matter how much you work on your serve, it could be down to the way they see the ball. A new study has shown that some people have better than average temporal resolution – meaning they are able to “see” more moving images per second than others, which gives them an in-built advantage when it comes to tracking fastmoving objects such as tennis balls. In order to gauge this, researchers set 80 men and women the “flicker test”, in which they looked at a light that was flickering increasingly quickly until it was so fast that it seemed to be still. Some people perceived the light as being static when it was flashing 35 times a second, others could still detect movement at more than 60 flashes a second, says the report in the journal PLOS One. “Some people really do seem to see the world faster than others,” said study co-author, associate professor Kevin Mitchell of Trinity College Dublin.
How to cut the risk of dementia
Scientists have identified the three most effective things people can do to cut their risk of dementia. These are: taking steps to avoid type 2 diabetes, avoiding traffic pollution, and drinking alcohol less often. The advice comes from a team at the University of Oxford who had previously identified a network of brain regions that are particularly vulnerable to Alzheimer’s. These areas process and combine data from our different senses, and deteriorate more quickly than other parts of the brain as we get older. For the new study, they examined the brain scans of 40,000 people to assess the health of these regions. They then used information about the participants’ health and habits to identify which modifiable risk factors – things we can change – had the biggest effect on these fragile areas. Also high on the “risk list” were poor sleep, excess weight, smoking and high blood pressure.