Philosophy of Genetics

The problem with Neuroscience

According to Cambridge University's Michael Bate, scientists who study the brain understand (to some degree) how individual neurons are created (a process called "neurogenesis").  They also understand how neurons move to their proper place ("axon guidance"), and form connections (called "synapses") with other neurons in the brain.
 
Yet, scientists still don't know how the "assembly of individual neurons in the brain" adds up to the development of human behavior.  Bate asks: "What can developmental genetics and neuroscience tell us about the transition from growth and patterning to the onset of function in a network and the emergence of behavior?"
 
What, it's been decades and you still don't know? Why do neuroscientists have such a hard time studying this?  Are their human pre-conceptions and biases getting in the way?  I can think of a few principles that may guide their approach:

First, neurons are experience.  A neuron's physical shape and configuration is a manifestation of evolutionary experience. They are not physical objects.  Neuroscientists should think less about neurons as objects, and more as manifestations of evolution.

Second, the neuroscientist who believes in "free will" or "nature vs nurture" is lost.  You can't study the mind or human intuition using intuition, the same way you can't study sub-atomic particles with measurement devices made of those same particles.

Third, there is no separation between the environment and the neuron's activity.  The neuron is designed to operate in the environment in which it evolved.  Neurons react to specific environmental inputs (situations) with a response that assists our survival (not necessarily a "rational" response).  Like an elevator that recognizes finger presses on its buttons and reacts with a response that is manifest in its design, there is no separation of "nature" (the elevator's design) from its "nurture" (presses on its buttons).  Its whole design anticipates that very specific experience.  Neurons are algorithms, with inputs and outputs, but the programming was built over millions of years in close association with the environment.

Fourth, humans are specialized actors.  We each differ by 1% of our DNA.  These "gene variables" in our DNA programming code act as master switches that differentiate us from our neighbor.  Some are motivated to lead, and some are motivated to follow.  This must be reflected in differential DNA and brain development some way.

Finally, scientists are loath to make discoveries that the public finds abhorrent.  And the public will not want to hear that most human preferences and motivations have a genetic basis (i.e. implying that their genes may be "flawed" in some way).  This fear will slow the progression of neuroscience, as scientists self-censor themselves in a search of public acclaim over the search for truth.

Thanks for the memory (again!)

A new study published in the Journal of Neuroscience has identified a “memory molecule” in the brain called “CaMKII”.  It turns out that in the area of the brain known as the hippocampus, you can artificially create and then biochemically erase short-term memories using the CaMKII protein molecule.

The Education of Bill Gates

Bill Gates recently told Time Magazine that "Learning is mostly about creating a context for motivation".  The Gates Foundation often provides funding for educational programs, and it's interesting to see his driving principles.

I agree that motivation is the key, since kids spend more time practicing things they're interested in ("time on task" leads to skill).  But by reading between the lines, I can see that Gates is ignoring the politically sensitive issue that some kids have a harder time learning than others, because their motivations themselves are innately different.  In other words, you can't teach the ability to be motivated, you can only exploit motivations that already exist in people, which have to come from within.  Some people have the "right ones" for a successful schooling experience, and others don't.

I think Bill Gates is proposing the creation of temporary, motivational frameworks using technology and other means.  In other words, teachers should find something (anything!) that motivates a child (and it may have to be customized for each child), and then use that motivation to keep them interested in the actual subject you want them to learn.

Anyway, this is what I imagine Bill Gates is talking about.  If a child is motivated only by sports (but hates geography), the teacher would create a sports games that teaches him geography as a biproduct.  Sounds like a nice approach at first glance.

But I believe the personalization and customization for each child would be prohibitively expensive, even for the Bill and Melinda Gates Foundation, due to differences in human nature among students.  Optimistically, Gates says in a recent Business Week article that "the setbacks don't mean they have squandered the $1 billion the foundation has spent so far."  Still, we may need to wait until version 3.0 of the program to get it right.

How memory works

An interesting article describes some of the latest research in how the brain forms memories.  There appears to be a "replay" mechanism, where the higher brain (neocortex) can query the part of the brain responsible for short term memory (hippocampus).

In other words, there is a "dialogue between the hippocampus, where initial memories of the day’s events are formed, and the neocortex, the sheet of neurons on the outer surface of the brain that mediates conscious thought and contains long-term memories."

The repeated cycles of brain activity also happen during sleep, leading researchers to believe that "that part of the function of sleep is to let us process and stabilize the experiences we have during the day".

Also, researchers at the University of Alabama recently found that a previously unknown process of DNA methylation (a genetic change that doesn't alter the underlying DNA sequence itself) can occur in the neurons of adult brains in response to life experiences, allowing for memory formation based on learned behavior.

Social neuroscience; or, Social behavior that changes the brain

According to a recent article, social neuroscience offers a window into how the brain processes social information.  Let's take a look at an example:

When a male cichlid fish loses its territory, that change in social status triggers dramatic changes in the fish’s brain.  (At least fifty genes are triggered, which cause some of its hormone-releasing neurons in the brain to become eight times smaller, which then leads to the shrinking of its sexual organs.)

Clearly, it's a complex mental exercise to determine that you've lost your territory, especially for a creature as instinctive as a fish.  How does a fish detect its change in social status?  Is there a "social status detection center" in its brain?  How is this detection hooked up to the genetic response in its "social brain"? 

Should be some interesting research coming out in this area, over the next few years.

The Expert Performance Movement

I have some more thoughts on the Expert Performance Movement (described in a recent NYT article).  They are a "loose coalition of scholars" trying to understand why some people are more talented than others at tasks like playing soccer.

They claim, for example, that a majority of World Cup soccer players are born in the first three months of the year.  This implies that talent cannot be genetic, because it would be absurd that "talent genes" are distributed unevenly to new babies over the course of the year.

Another claim they make is that anyone (regardless of their genes) can become an expert in memorizing numbers, if they spend enough time practicing.  So that is another talent that's not innate, they say.

The problem with all of these claims is either: (1) the researchers create artificial situations in the lab (e.g. memorizing numbers) that nobody would want to practice in the real world, or (2) the researchers refuse to think deeply about alternative explanations to show how something could be innate. 

For example, if it's true that world-class soccer players tend to be born in January through March, what could explain this?  Certainly their mothers (from whom they receive half their genes) tend to conceive after the soccer season (in which their fathers may be competing).  In other words, soccer-playing parents tend to have soccer-playing kids, due to the genes they pass on.  With enough creative thinking, you can think of many other plausible genetic explanations for talent.

A star is born

A recent New York Times article repeats a common fiction about human nature, which goes like this:

1. Humans are better at doing something when they spend lots of time practicing it
2. Our talents are thus not inborn or innate -- they just require constant practice (and time on task)
3. Therefore, students "should be taught to follow their interests earlier ... to build up their skills"

Can you spot the fallacy here?  The article (which reviews a book called "Cambridge Handbook of Expertise and Expert Performance") assumes that our "interests" themselves are not innate.  But we have seen many times that this is incorrect -- our motivations and desires are certainly innate, and you can't teach motivation.

So let's re-state the argument correctly:

1. Humans have innate (genetic) interests and desires
2. This leads them to spend more time on some tasks than others
3. Spending more time on a task makes you more talented at that task
4. Therefore, talent is innate!

"Intelligent" brains develop differently

According to a recent New York Times article:

[R]esearchers found that average children (I.Q. scores 83 to 108) reached a peak of cortical [brain] thickness at age 7 or 8. Highly intelligent children (121 to 149 in I.Q.) reached a peak thickness much later, at 13, followed by a more dynamic pruning [thinning] process.

One interpretation ... is that the brains of highly intelligent children are more plastic or changeable, swinging through a higher trajectory of cortical thickening and thinning than occurs in average children. The scans show the "sculpturing or fine tuning of parts of the cortex which support higher level thought, and maybe this is happening more efficiently in the most intelligent children".

Genes and the invention of writing

As we have seen, human genes have continued to evolve as recently as 5,000 years ago, a time which saw an explosion in human inventiveness and creativity.  Let's review what humans invented 5,000 years ago in the Middle East:

• The wheel (originally used for pottery)
• Written language, based on a small number of reusable syllables
• Mathematics, originally based on a unit of 60 instead of 10

So what changed in the human mind 5,000 years ago that allowed such creativity?  And how did changes in our genes enable it to happen?  I believe humans changed then in two fundamental ways:

• Humans began to think more abstractly
• Humans became willing to die for abstractions

An abstraction is a way of explaining many separate experiences or occurrences as if they had something in common.  Writing "iii" to represent three animals, for example, is an abstraction.  Abstractions allows you to make statements about similar concepts, instead of treating every situation as a unique occurrence.  This is extremely powerful, since it allowed us to replace unwritten customs with written laws.

At some point, humans started having emotional relationships with their abstractions.  The emotional connection superceded man's own sense of self-preservation, in some cases.  Humans adhered to abstract laws and became incensed by injustice.  Many became religious zealots, which gave them the motivation to spread faith in an abstract God and divine truth.  Man's dignity invested him in abstractions, and he became willing to fight to the death for them.  That allowed abstractions to flourish, and be transmitted to others.

The "Jennifer Aniston" Neuron

Recent research has shown that we may remember certain concepts, ideas, or people (such as "Bill Clinton" or "Jennifer Aniston" or my "grandmother") using a single neuron in the brain.  In other words, our memories are not holistically (or holigraphically) spread across the brain, but may be stored in very specific locations.

When we learn a new concept, it is temporarily stored as "short-term memory" by neurons in the center of the brain (in the hippocampus and related regions).  For example, the first time you saw "Jennifer Aniston" on TV, your hippocampus stored the "Jennifer Aniston" concept in your short-term memory.  Later, that memory was transferred to your higher brain (the cortex), which resembles an enormous switchboard of neurons.  It seems that the memory gets further refined into a pure concept over time, represented by fewer and fewer neurons, until it is represented by a single neuron.

This research has implications for how our genes can affect our personality.  If our mental concepts are stored all over the brain, it wouldn't be possible for our genes to exploit them.  But if our memories are consolidated and categorized (e.g. keep all memories of pretty girls stored in the same place), a genetic signal (or a boost of testosterone?) could affect how we use those memories.

The Limbic System

The limbic system--the centre of our brain--comprises several subcomponents, including the hypothalamus, the hippocampus, and the amygdala.

The amygdala screens input from the senses and attaches significance to them. The main thing to remember about the amygdala, so that there arises no reductionist debate about "little men" inside our brain, is that it can only recognise very vague patterns in our sensory input, and it can only react in very simplistic, stereotyped ways. Its power is in colouring the sheer number of daily sensory experiences we have, not in completely understanding any one of them.

The hippocampus acts as our short-term memory bank, keeping many items in its store until the amygdala can assess them and determine if they are worth remembering, and thus transfer them to the higher brain's long-term memory.

The hypothalamus is the enactor of emotion. It can signal the pituitary gland to secrete hormones, or it can itself induce pleasure, fear and other strong emotions. How does it do this? By helping the amygdala, in certain situations, to shut down or incite various parts of our brain (often our rational brain) so that more primal reactions can take over. For example, if the amygdala detects a situation for which it wants to induce the fear response, it signals the hypothalamus, which in turn signals for the release of adrenaline. Perhaps it also helps to shut down parts of the frontal cortex responsible for planning and rational behaviour. We may not feel like ourselves in this state, but the brain is operating quite normally, though more through the inner eye than the "higher" cortex, over which we have more conscious control.

Notice that the inner eye "knows" where the higher brain's capacities are stored. It knows that the brain's centre for rational planning is in the frontal cortex. It knows that the facial recognition centre is in the bottom of the brain. It knows because it put them there.

The inner eye is not only responsible for some of the brain's responses, but its development as well. It uses this knowledge to support and exploit abilities we can only gain through experience. So the inner eye can induce us to plan to hunt and kill an enemy, or it can cause us to be shamed by a parent's scowling face. But not everyone has the same reaction to the same stimulus, because everyone's inner eye is different.

Thanks for the Memory

Slate magazine recently published a couple of stories about the arrival of new memory drugs and memory enhancement techniques.  These will be godsends for an aging populace suffering from mild cognitive impairment.

What is probably more interesting is why we remember what we do.  Certainly we remember what interests us (and excites us, motivates us, drives us, etc), and we forget what doesn't.

The amygdala (in the center of the brain) helps to process and categorize our experiences.  Is the structure of the amygdala different among the population, leading boys to be more interested in trains and girls more interested in dolls?  Is it responsible for causing some to be interested in seeking power, whereas others are only interested in seeking approval?

What is the Inner Eye?

When we think of the brain, we usually think of a lump of undifferentiated gray matter, made up of neurons. But the brain actually has a quite complex internal structure, laid out very specifically by the genes, to allow it to encode and store our experience.
   
As we evolved from the apes, and they from reptiles and other creatures before them, our brain evolved as well. Pieces were added, but rarely removed, building on previously evolved parts of the brain. The most ancient section, the limbic system, or what I call the inner eye, is a relic from our reptilian ancestors. It lies at the center of the brain, and is almost completely genetically laid out, unlike our higher brain, the cortex, which is laid out more flexibly to be shaped by our experience.

Interestingly, information from all the senses (touch, smell, hearing, tasting and seeing) passes through the inner eye before being routed to the higher brain. In other words, nerves from our senses relay information through the inner eye, where their signals can be nuanced, enhanced, ignored, or otherwise colored, before they are processed by the cortex, and our higher consciousness.
       
This lends the genetically-laid-out part of the brain--the inner eye--a powerful means of control over us. In fact, it determines who we are. We remember what interests us, and we forget what doesn't. We pursue what drives us, and we ignore what doesn't. We take the path of least resistance in life, with resistance defined by what experiences resonate with our inner eye. If our inner eye thrives on novelty, then we will always seek novelty. If not, then not.

There is a distribution of inner eyes across people, so no two people are motivated by the same experience. The inner eye thus determines our temperament, and who we can become. This obviously has dire consequences for free will.

One important thing to keep in mind about the inner eye, however, is that it can only recognize vague invariant patterns in the environment similar to those in the State of Nature. It has no power by itself to plan or recognize more complex or modern objects. For this it must exploit its knowledge of the higher brain to do its bidding.

How can we feel an emotion toward an object that didn't exist when we evolved?

You may ask how we can feel an emotion toward modern objects which didn't exit in the State of Nature. Have you ever felt envy (a natural emotion) toward another person's computer (an object only now part of the nurturing environment)?

Actually, it is not too hard for the genes to encode a disposition in the inner eye toward a general category of "novel objects"--in other words, objects which are rare and unusual in the current environment. The inner eye may do this, for example, by employing the facial recognition center in the cortex to detect if an emotion, such as pleasure, is found on another person's face, and then induce greed and envy upon the object of that pleasure.

Some things not present in the State of Nature, such as chemotherapy, may throw off our innate responses, however. If a cancer patient eats maple ice cream and then later undergoes chemotherapy, the inner eye relates the resulting sickness to the ice cream, not the treatment. The patient may be forever sickened by maple ice cream in the future, but feels no additional fear of the next chemo session. We have strong innate reactions to certain experiences over others.

You can't teach motivation

You can motivate people, but you can't teach motivation.  In other words, you can exploit people's existing motivations, but you can't give them entirely new motivations.

For example, my son is very motivated and excited when he sees a bus go by.  "Daddy, see the bus, the bus!"  If I want to get him motivated about a long car trip, I can mention the fact that we will see buses.  But I can never get him excited about being in crowds, no matter how hard I try.  He just becomes agitated.

My daughter, on the other hand, loves crowds.  She goes up to other children and asks if they want to play.  Most of them reject her (out of shyness and other reasons), but she persists and always finds the one or more children in the room who want to play with her.  My son is more affected by rejection, and he doesn't persist as long.

Why are my children the way they are?  Did I teach my son to be excited by buses?  How would I do that?  How can you teach an emotion?  Can I invent an entirely new emotion (say, teaching him to be motivated at the sound of nails being dragged across a blackboard)?

Why are my children different from each other?  Did I raise them both differently?  Did I teach my daughter to be more resilient in the face of rejection?  Did I teach my son to get agitated when in crowded settings?

No.  You can't teach motivation.  If someone is motivated to be a leader, you can certainly help them reach their potential.  But if someone else is not motivated to be a leader, you can't make them a leader.  They will get agitated and depressed.  But they will probably tell you that they could have been a leader, yet simply chose not to be one of their own free will!