Researchers from London and Italy have just published a study on the brain areas involved in perceiving and understanding faces. They created an elegant experiment where they used morphing to compare how brain activity changes as a photograph is gradually blended from one person to another, for example, from Marilyn Monroe to Margaret Thatcher.
They found that the brain did not respond in the same gradual manner, and that activation shifted to specific areas at certain points in the blending process. When the blending was in its early stages, participants perceived the picture as the same person with physical changes to their face, an experience which caused activation in the inferior occipital gyrus. When the level of blending affected recognition of the pictured person, the right fusiform gyrus was activated, an area thought to be involved with judgements of familiarity for faces. When a participant was already familiar with the people in the pictures, the temporal lobes became active when the final face became clear. These areas have been linked to semantic memory and naming.
This study is important as it shows specialised areas of activation for different stages in the face perception process in a single experiment.
These stages have been hypothesised to exist for quite some time in a model developed by psychologists Vicki Bruce and Andy Young, largely from studies on people with prosopagnosia, a condition where face recognition can be impaired, usually after brain damage.
Link to BBC News story.
Link to story in The Guardian.
Link to abstract from Nature Neuroscience.
This is a hack which never made it into the book, but we thought it worth sharing. At this point, to get the most out of this hack, look at this figure (in a pop-up window) quickly before reading on. It’s not important to try and work out what it is, but have a good look. Seen it? Now, without further ado…
Hack #102: Alter Input With Expectation
The balance between feed-forward and feed-back connections in the brain gives a clue to the balance between raw sensation and expectations in constructing experience.
Feedback is ubiquitous in the brain. The brain is not just massively parallel [Hack #52], it is also massively interconnected- an awesomely complex cybernetic system.
Continue reading “Hack #102 : Alter Input With Expectations”
Our heroic contributor Alex Fradera has a nice way with some kind words about the book here
Suffice to say that if you want to know about the brain, and the mind, and you want a bunch of mavericks to illuminate it using cognitive and visual illusions, pop culture and web-references, wrapped up in a very chic, sleek simple design, you couldn‚Äôt go far wrong
Need To Know give us a mention too (cheers guys) and we got our first review at amazon.com which was four stars and said, amongst other things that the book is ‘unconventional in several ways’ – which i like!
Controversy has erupted over Michael Persinger’s findings that applying weak complex magnetic fields over the temporal lobes can induce unusual experiences, particularly the experience ‘sensing a presence’ in the room, which Persinger has linked to religious belief and spiritual experience.
This work was part of a larger project in which Persinger and his colleagues have reported strong links between temporal lobe disturbance and anomalous beliefs and experiences throughout the population.
However, a group of Swedish neuroscientists led by Pehr Granqvist have reported that they’ve failed to replicate Persinger’s results with magnetic stimulation when they used a double blind approach to running their experiments (where neither the experimentor nor the participant knows whether they are getting magnetic stimulation).
Persinger has replied by stating that the Swedish study was not an accurate replication.
Link to story on nature.com
The second part of a three part neuroscience tutorial has just been published on kuro5hin.org. While the first part covered the basic physiology of the neuron and how signals are generated and propogate within them, the second part deals with how signals are passed between neurons, over the synapse.
The synapse is the principal part of the neuron where neurotransmitters are released. Because of this, it is where most psychoactive drugs have their effect, which often work by mimicking or altering the normal function of neurotransmitters as they communicate signals throughout the brain and other parts of the nervous system.
Psychologists from the University of Oregon have been studying children’s imaginary friends. Their study found that 65% of children had imaginary friends at the age of 7, a much higher rate than expected, and that the presence of an imaginary friend is linked to better emotional understanding and ‘theory of mind’ skills (the suggested ability that allows us to figure out and represent others’ beliefs and intentions).
Other studies on imaginary friends in children have also shown that they seem to be quite normal and generally linked to positive psychological development.
Interestingly though, some of the children report that their imaginary playmates don’t always do what they’re told and sometimes won’t go away when expected to, or bother them inconveniently. It seems that even from quite a young age, we are not always master of our own imaginations.
Link to story in Seattle Post-Intelligencer.
A study investigating the number of left-handed people in tribal societies has found that the more violent the society, the higher the number of left-handers in the population. The researchers speculate that this is due to left-handers having an advantage in hand-to-hand combat, as shown by the higher number of left-handed champions in sports like boxing and fencing.
Some researchers have linked left-handedness to neurobiological stress during the early stages of brain development, so it has been a puzzle why left-handedness remains a common trait in the population, when this sort of biological stress has been linked to other, less advantageous traits, such as higher rates of nervous system and immune system disorders.
The advantage in combat may be one way (among, potentially, many others, including better non-verbal intelligence) in which left-handers have an edge on their right-handed peers.
Link to story on nature.com