On Twitter this week I joked that neuroscientists could save money on brain scanners by just asking people how active their brains are.Read More
Last month, I blogged about the famous Libet experiment and how this 1983 study, which was once heralded as undermining the concept of free conscious will, has now been reinterpreted in a less radical way.
Libet et al. found an electrical potential, the Readiness Potential (RP), that emerged in the brain about 1 second before the onset of voluntary movement. The key finding was that the RP also preceded the conscious intention to move. This seemed to suggest that the brain was ‘deciding to move’ before the conscious mind.
However, recent work by neuroscientist Aaron Schurger and colleagues cast doubt on this interpretation. Schurger et al. argued that the RP is not actually a marker of a decision process in the brain, but merely reflects random brain fluctuations that might influence decisions.
But now, in an interesting twist, a new paper has appeared that casts doubt on Schurger’s theory. And – double twist – Schurger is one of the authors.Read More
A recurring theme in evolutionary psychology is that humans did not evolve to live in the modern world. Homo sapiens emerged in the harsh conditions of small hunter-gatherer societies of the Pleistocene era. Then, in just a few thousand years, we found ourselves in a very different world of big cities, fast food and all the rest. This change happened so suddenly that evolution had no time to adapt us to the new world.
As one early evolutionary psychology text put it, “Few fear motor cars, guns, cigarettes, or alcohol, despite knowing that these now kill far more people than do snakes, spiders, or sharks. Not having been present long enough to materially alter our genetic endowment, such modem perils are feared too little.”
This ‘maladapted mind’ trope has appeared in countless forms since, but I’ve never seen anyone ask what a perfectly modern-adapted human would be like. So let’s speculate about this.Read More
A very weak paper in PNAS has attracted some attention lately: An experimental test of the ovulatory homolog model of female orgasm
The paper aims to be a test of the hypothesis that the human female orgasm is a kind of evolutionary relic from an earlier stage in evolution.Read More
One of the best known of all neuroscience studies is the ‘free will experiment’ conducted by Benjamin Libet and colleagues in 1983.
Libet et al. asked volunteers to tap their fingers at will, freely choosing the time of each action. EEG revealed an electrical potential occuring “several hundred milliseconds” before people reported a conscious decision to perform each tap.
This “Readiness Potential” or Bereitschaftspotential threatened to debunk the very existence of human volition. Libet’s results suggested that decisions were made, unconsciously, by the brain, and only later made it into consciousness, once the decision signal had become strong enough.
Now, an excellent article by Bahar Gholipour in the Atlantic looks at how more recent work has effectively debunked the radical interpretation of the Libet experiment. But has it de-debunked free will?Read More
A paper about electrical activity in cultured human brain cells got a lot of attention this week:Read More
The Swiss psychoanalyst Carl Jung (1875-1961) was one of the best-known psychologists of the 20th century. He introduced such famous concepts as introverted and extraverted personalities, and the idea of the psychological ‘complex’.
The letter acknowledges that Jung’s writings contained racism, and apologizes for the failure of Jungians to confront this fact earlier.Read More
Left-handed people are under-represented as volunteers in human neuroimaging studies, according to a new paper from Lyam M. Bailey, Laura E. McMillan, and Aaron J. Newman of Dalhousie University.
Bailey et al. analyzed a sample of 1,031 papers published in 2017, finding that just 3.2% of participants were non-right-handed, even though this group makes up about 10-13% of the general population.Read More
The brain is buzzing with gamma oscillations – cycles of neuronal activity with a frequency (around 40-60 Hz) higher than that of other major brain waves.
A longstanding hypothesis is that gamma serves as a kind of ‘clock signal’ that enables the coordination and integration of signals. Gamma has even been proposed as the mechanism by which the brain ‘binds’ information from different brain areas into a unitary consciousness.
However, while the gamma-clock hypothesis is intriguing, direct evidence for it has proved elusive. Many researchers now believe that gamma is merely a non-specific marker of neuronal activity.
Now, in a new paper out in Neuron, researchers Hyeyoung Shin and Christopher I. Moore announce the discovery of a new class of neurons that seem to have clock-like properties, and firing regularly at gamma frequencies. This could help to put the gamma-as-clock theory back on the map.Read More