People under the influence of psychedelic drugs attain a "higher" state of consciousness, scientists say.
A team led by neuroscientists from the University of Sussex observed a sustained increase in neural signal diversity - a measure of the complexity of brain activity - in people under the influence of psychedelic drugs, compared with when they were in a normal waking state.
The diversity of brain signals provides a mathematical index of the level of consciousness.
For example, people who are awake have been shown to have more diverse neural activity using this scale than those who are asleep.
The new study, however, is the first to show brain-signal diversity that is higher than baseline, that is higher than in someone who is simply "awake and aware".
Previous studies have tended to focus on lowered states of consciousness, such as sleep, anaesthesia, or the so-called "vegetative state".
The team re-analysed data that had previously been collected by Imperial College London and the University of Cardiff in which healthy volunteers were given one of three drugs known to induce a psychedelic state: psilocybin, ketamine and LSD.
Using brain imaging technology, they measured the tiny magnetic fields produced in the brain and found that, across all three drugs, this measure of conscious level - the neural signal diversity - was reliably higher.
The team says that more research is needed using more sophisticated and varied models to confirm the results but they are cautiously excited.
"This finding shows that the brain-on-psychedelics behaves very differently from normal," said Professor Anil Seth, co-director of the university's Sackler Centre for Consciousness Science.
"During the psychedelic state, the electrical activity of the brain is less predictable and less 'integrated' than during normal conscious wakefulness - as measured by 'global signal diversity'.
"Since this measure has already shown its value as a measure of 'conscious level', we can say that the psychedelic state appears as a higher 'level' of consciousness than normal - but only with respect to this specific mathematical measure."
Will Earth-like planets have Earth-like oceans?
Nasa's latest mind-blowing revelation suggested that life could dwell in an ocean beneath the icy crust of Enceladus, Saturn's sixth-largest moon.
But any water-bearing planet like our own has to meet a complex set of requirements.
For a planetary surface to boast extensive areas of both land and water, a delicate balance must be struck between the volume of water it retains and the capacity of its oceanic basins.
Each of these two quantities may vary substantially across the full spectrum of water-bearing worlds.
Why the Earth's values are so well balanced is an unresolved and long-standing conundrum.
But a new paper, just published by Fergus Simpson of the Institute of Cosmos Science at the University of Barcelona, sheds some new light on the puzzle.
Simpson constructed a statistical model to predict the division between land and water on habitable exoplanets, which suggested those most liveable were dominated by oceans spanning over 90 per cent of their surface area.
This conclusion is reached because the Earth is in close proximity to the "waterworld limit", a regime where the existence of our species would no longer be viable.
"A scenario in which the Earth has less water than most other habitable planets would be consistent with results from simulations, and could help explain why some planets have been found to be a bit less dense than we expected," Simpson explained.
He further found the Earth's finely balanced oceans may be a consequence of the anthropic principle - more often used in a cosmological context - which accounted for how our observations of the universe are influenced by the requirement for the formation of conscious life.
"Based on the Earth's ocean coverage of 71 per cent, we find substantial evidence supporting the hypothesis that anthropic selection effects are at work."
At 25, you're at your most random
People's ability to make random choices or mimic a random process, such as coming up with hypothetical results for a series of coin flips, peaks around age 25.
That's according to French scientists who believe that the ability to behave in a way that appears random arises from some of the most highly developed cognitive processes in humans, and may be connected to abilities such as human creativity.
Previous studies have shown that ageing diminishes a person's ability to behave "randomly".
However, it had been unclear how this ability evolves over a person's lifetime, nor had it been possible to assess the ways in which humans may behave randomly beyond simple statistical tests.
To better understand how age impacts random behaviour, Dr Nicolas Gauvrit and colleagues at Paris research institute LABORES assessed more than 3400 people aged between 4 and 91.
Each participant performed a series of online tasks that assessed their ability to behave randomly.
The five tasks included listing the hypothetical results of a series of 12 coin flips so that they would "look random to somebody else," guessing which card would appear when selected from a randomly shuffled deck, and listing the hypothetical results of 10 rolls of a die - "the kind of sequence you'd get if you really rolled a die."
The scientists analysed the participants' choices according to their algorithmic randomness, which was based on the idea that patterns that were more random are harder to summarise mathematically.
After controlling for characteristics such as gender, language, and education, they found that age was the only factor that affected the ability to behave randomly.
This ability peaked at age 25, on average, and declined from then on.
The study authors described the test as a "kind of reverse Turing test" for random behaviour, a test of strength between algorithms and humans.
"25 is, on average, the golden age when humans best outsmart computers," Gauvrit said.
The study also demonstrated that a relatively short list of choices, such as 10 hypothetical coin flips, could be used to reliably gauge randomness of human behaviour.
The authors were now using a similar approach to study potential connections between the ability to behave randomly and such things as cognitive decline and neurodegenerative diseases.