Letters archive

Michael Le Page reports on a possible genetic advantage for blue eyes: the ability to see better in low light. Meanwhile, your review of Liat Yakir's book, A Brief History of Love , notes her proposal that blue eyes are evidence for the relative success of sexual selection for this trait, people being "attracted to …

The argument advanced in the book Filterworld , the subject of your review, is that the shift towards algorithmically curated feeds has homogenised culture. I would argue that it may also polarise culture. Take book recommendations of the type "Readers who bought Book X also bought Book Y". If one reader's first selection was The …

Using the word "botched" to describe the landing of Japan's SLIM lunar probe isn't appropriate. You say that one of its thrusters failed during the descent. In spite of that, the plucky craft landed in one piece, sent some pics, went to sleep and then reawakened. "Off-nominal" or a similar word would have been a …

In my experience of memory retention, it seems that, at the time this occurs, the brain – consciously or unconsciously – places a memory into a category with a rating of importance varying from "retention essential" to "almost discardable". Memories in the top category can be retained almost indefinitely, while those in the lowest, although …

If thinking hard doesn't cause the brain to consume more energy, it doesn't make evolutionary sense that stress hormone levels rise when we need to concentrate. It is well known that elite chess players lose weight during tournaments . Even though the brain is only responsible for a small percentage of the extra calories burned, …

Jeffrey Lapides has discovered microbes in the brain seemingly implicated in Alzheimer's disease, an unexpected finding. Will this, and similar discoveries, signal a rethink about neurological and mental illnesses? Suspicions must arise that, overall, this may not be a benign microbiome, especially if pathogens are entering the brain. We have medicines that act on some …

Your look at cannibalism mentioned that over the course of history, the practice "has been surprisingly common". In fact, this shouldn't be surprising at all. Cannibalism solves the food shortage problem and is environmentally friendly. So why not? The real question should be: why did cannibalism all but vanish from the culture of Homo sapiens …

The gains from flitting between foraged food sources may not have promoted what we call ADHD. Instead, look at birds feeding on the ground. They don't hang around to pick up the food for a long time, but make frequent, random movements away to different places. This makes it harder for a stealthy predator to …

Here is a commercial application of dream engineering that I would welcome. Many people experience leg cramps at night, incidents where, in the middle of sleep, your leg turns into stone. It is very painful. Dream engineering might be able to implant the suggestion that our legs should remain relaxed during sleep. People would pay …

I read your story on making jet fuel from carbon dioxide and it struck me that for this to succeed commercially, all it needs is a place that can generate lots of clean energy, has capital to invest in the infrastructure and has a need to replace an oil-dependent economy. I hope it really is …