The mammalian cortex is not specialized for particular tasks—this is the primary advantage of it’s architecture over it’s predecessors (at the cost of a much larger size than more specialized circuitry).
How do you reconcile this claim with the fact that some people are faceblind from an early age and never develop the ability to recognize faces? This would suggest that there’s at least one aspect of humans that is normally somewhat hard-wired.
I’ve read a great deal about the cortex, and my immediate reaction to your statement was “no, that’s just not how it works”. (strong priors)
About one minute later on the Prosopagnosia wikipedia article, I find the first reference to this idea (that of congenital Prosopagnosia):
The idea of congenital prosopagnosia appears to be a new theory supported by one researcher and one? study:
Dr Jane Whittaker, writing in 1999, described the case of a Mr. C. and referred to other similar cases (De Haan & Campbell, 1991, McConachie, 1976 and Temple, 1992).[7] The reported cases suggest that this form of the disorder may be heritable and much more common than previously thought (about 2.5% of the population may be affected), although this congenital disorder is commonly accompanied by other forms of visual agnosia, and may not be “pure” prosopagnosia
The last part about it being “commonly accompanied by other forms of visual agnosia” gives it away—this is not anything close to what you originally thought/claimed, even if this new research is actually correct.
Known cases of true prosopagnosia are caused by brain damage—what this research is describing is probably a disorder of the higher region (V4 I believe) which typically learns to recognize faces and other complex objects.
However, there is an easy way to cause prosopagnosia during development—prevent the creature from ever seeing faces.
I dont have the link on hand, but there have been experiments in cats where you mess with their vision—by using grating patterns or carefully controlled visual environments, and you can create cats that literally can’t even see vertical lines.
So even the simplest most basic thing which nature could hard-code—a vertical line feature detector, actually develops from the same extremely flexible general cortical circuit—the same circuit which can learn to represent everything from sounds to quantum mechanics.
Humans can represent a massive number of faces, and in general the brain’s vast information storage capacity over the genome (10^15 ish vs 10^9 ish) more or less require a generalized learning circuit.
The cortical circuits do basically nothing but fire randomly when you are born—you really are a blank slate in that respect (although obviously the rest of the brain has plenty of genetically fixed functionality).
Of course the arrangement of the brain’s regions with respect to sensory organs and it’s overall wiring architecture do naturally lead to the familiar specializations of brain regions, but really one should consider this a developmental attractor—information is colonizing each cortex anew, but the similar architecture and similarity of information ensures that two brains end up having largely overlapping colonizations.
How do you reconcile this claim with the fact that some people are faceblind from an early age and never develop the ability to recognize faces? This would suggest that there’s at least one aspect of humans that is normally somewhat hard-wired.
There are all sorts of aspects of humans that are normally somewhat—or nearly entirely—hard-wired. The cortex just doesn’t tend to be. Even the parts of the cortex that are similarly specialised in most humans seem to be so due to what they are connected to. (As can be seen by looking at how the atypical cases have adapted differently.) It would surprise me if the inability to recognise faces was caused by a dysfunction in the cortex specifically.
Disclaimer: I disagree with nearly everything else Jacob has said in this thread. This position specifically appears to be well researched.
How do you reconcile this claim with the fact that some people are faceblind from an early age and never develop the ability to recognize faces? This would suggest that there’s at least one aspect of humans that is normally somewhat hard-wired.
I’ve read a great deal about the cortex, and my immediate reaction to your statement was “no, that’s just not how it works”. (strong priors)
About one minute later on the Prosopagnosia wikipedia article, I find the first reference to this idea (that of congenital Prosopagnosia):
The idea of congenital prosopagnosia appears to be a new theory supported by one researcher and one? study:
The last part about it being “commonly accompanied by other forms of visual agnosia” gives it away—this is not anything close to what you originally thought/claimed, even if this new research is actually correct.
Known cases of true prosopagnosia are caused by brain damage—what this research is describing is probably a disorder of the higher region (V4 I believe) which typically learns to recognize faces and other complex objects.
However, there is an easy way to cause prosopagnosia during development—prevent the creature from ever seeing faces.
I dont have the link on hand, but there have been experiments in cats where you mess with their vision—by using grating patterns or carefully controlled visual environments, and you can create cats that literally can’t even see vertical lines.
So even the simplest most basic thing which nature could hard-code—a vertical line feature detector, actually develops from the same extremely flexible general cortical circuit—the same circuit which can learn to represent everything from sounds to quantum mechanics.
Humans can represent a massive number of faces, and in general the brain’s vast information storage capacity over the genome (10^15 ish vs 10^9 ish) more or less require a generalized learning circuit.
The cortical circuits do basically nothing but fire randomly when you are born—you really are a blank slate in that respect (although obviously the rest of the brain has plenty of genetically fixed functionality).
Of course the arrangement of the brain’s regions with respect to sensory organs and it’s overall wiring architecture do naturally lead to the familiar specializations of brain regions, but really one should consider this a developmental attractor—information is colonizing each cortex anew, but the similar architecture and similarity of information ensures that two brains end up having largely overlapping colonizations.
There are all sorts of aspects of humans that are normally somewhat—or nearly entirely—hard-wired. The cortex just doesn’t tend to be. Even the parts of the cortex that are similarly specialised in most humans seem to be so due to what they are connected to. (As can be seen by looking at how the atypical cases have adapted differently.) It would surprise me if the inability to recognise faces was caused by a dysfunction in the cortex specifically.
Disclaimer: I disagree with nearly everything else Jacob has said in this thread. This position specifically appears to be well researched.