Chinese scientists tackle conundrum of why humans are brighter than animals with bigger brains
Answer may lie in our ability to create information-relaying particles using much less energy than other species, making our brains more efficient, researchers suggest
Chinese scientists have suggested a new theory as to why people are so much more intelligent than animals even though our brains are sometimes much smaller than those of other species.
Researchers at the Wuhan Institute of Neuroscience and Neuro-engineering have previously carried out studies backing the scientifically contentious idea that the brain not only processes and passes on information through electrical and chemical signals, but also with photons, a form of tiny particle that can include light.
In their latest study, the researchers said human brains are able to create information-relaying photons using much less energy than other animals, which suggested they are able to operate more speedily and efficiently than those of other species.
The hypothesis that our brain also operates using other mechanisms rather than just electrical and chemical signals has been around for decades.
Its supporters have included the physicist Eugene Wigner, Nobel Prize laureate in 1963 and more recently the eminent physicist Sir Roger Penrose at the University of Oxford.
These theories include the idea that the brain transmits non-electrical particles, a form of physics which also underpins the idea of the quantum computer.
But other scientists have remained sceptical, with one of their biggest concerns the absence of a physical medium in the brain through which information is transmitted.
A research team led by professor Dai Jiapei at the Wuhan institute suggested two years ago that neurons, nerve cells in the brain that transmit information, can emit photons.
They were extremely weak, detectable only with the most sensitive equipment, but capable of transmission along brain fibres and circuits, the researchers said.
The generation and transmission of these extremely faint “lights” in the brain was stimulated by a chemical called glutamate, which is commonly used as a flavour additive in food.
In their latest study, Professor Dai and his colleagues sliced tissue samples from the brains of a bullfrog, mouse, chicken, pig, monkey and human.
The neurons, still alive in the culture dish, were then stimulated with glutamate and the photons recorded with specially-built sensors.
They observed the spectral redshift, or the change of light waves from higher to lower energy levels.
Human brain tissue showed the lowest energy photons, followed by the monkey, pig, chicken and mouse, with the frog at the highest level.
“Interestingly, we found that the chicken exhibits more redshift than the mouse, raising the question of whether chickens hold higher cognitive abilities than those of mice,” the researchers wrote in their paper published in the Proceedings of the National Academy of Sciences in the United States.
“It has been suggested that birds might have evolved from a certain type of dinosaur and that dinosaurs, which dominated on Earth for a long time, should hold certain advanced cognitive abilities over other animals. Based on this theory, it may be true that poultry have higher cognitive abilities than rodents, at least in language abilities, because certain birds, such as parrots, are able to imitate human words,” the researchers wrote.
The authors said they hoped the findings would suggest a new viewpoint in understanding the mechanisms of the brain and also explain why human brains were better than those of other animals in some advanced cognitive functions, such as language, planning and problem solving.
Traditional measurements such as brain size cannot fully explain differences in intelligence, they said. Elephants, for example, are not smarter than humans and dolphins can outwit whales.
The authors stress, however, that some crucial questions remained unanswered.
It is still not clear, for example, how the brain carries out the transfer of information, coding and storage via photons.
Critics of the “quantum brain” theory have also questioned whether the brain is physically able to relay information through photons.
“The critical questions we are here concerned with is whether any components of the nervous system ... wet and warm tissue strongly coupled to its environment - display any macroscopic quantum behaviours, such as quantum entanglement,” wrote Professor Christof Koch and Professor Klaus Hepp at the University of Zürich in a 2007 paper.