Making Choices

I had an interesting conversation over the weekend with some friends, about the processes involved in making choices. I learned that not everyone has heard as much about these sorts of things as I have. And since I've found the knowledge to be liberating and tremendously useful, I thought it might be a good idea to present it here.

First, a disclaimer: I'm neither a psychologist nor a neurologist. My understanding of these things comes from the sorts of books and blogs I like to read, and podcasts I like to listen to. Usually, the sources they come from are experts (often actual psychologists and neuro-scientists), so I'm pretty confident in their reliability. That said, I'm going to be reproducing a lay-person's understanding of these things, which is probably not a reliable source (read: it's probably way over-simplified and most likely wrong in a lot ways). If you're interested in a more detailed (and probably more accurate) understanding of this, I'd suggest further reading. But I hope you'll find this a useful and enlightening starting point.

The first thing we need to agree on is that the brain is where all the action happens. It's not only where memories are stored, but it's where all sensory information is processed and consciousness is somehow generated. We know that this is true, because decades of medical records show that damage to the brain impairs the ability to recall memories, to perform tasks and to process sensory information.

But it goes one step further: damage to specific parts of the brain can impair specific functions. That implies that the brain has a kind of modular structure: different bits have different functions. When they work together they do the things we know the brain does. Neuro-scientists have very sophisticated instruments that can observe those different areas operating distinctly, but together, and working to produce the subjective experience of life.

But they've also learned some other interesting things. When a certain part of the brain is damaged, the person isn't necessarily aware of the damage. They might not even notice that a certain set of tasks they used to be able to perform are no longer available to them. This could be some missing memories, an inability to recognise faces, even an inability to see (something you'd think people might notice!).

What that tells us is that the brain isn't very good at internal diagnostics. It's not really capable of doing a self-check to make sure that everything's in working order... it just keeps going as if the damaged part is working normally. That means that our conscious experience doesn't really include any awareness of how our brain is functioning: There are processes going on inside us that we're completely unaware of, even in a perfectly healthy brain.

Another important point is the way the different parts of the brain are put together. They're not just all squeezed together in a lump - there's a specific structure at work. To understand this structure better, we need to understand a little about evolution.

Although all living things on Earth are related to each other, not all living things have brains. Only a small portion of us have those. Most multi-cellular animals have a kind of nervous system - a specific set of cells that act as a communications network between the the various parts of the body. The nervous system helps to coordinate things, like moving around, breathing, eating, pumping blood and so on. Many of the more complex kinds of animals have a central core, where the processing of commands for the nervous system happens - that's what the brain is.

Larger and more complex animals have brains that can do more than just coordinate things and process sensory information: they can store memories, evaluate threats in the environment and make decisions about how to react to a given set of circumstances.

A small sub-set of those can do even more complicated things: they can recognise specific individual members of their own species (which allows them to interact socially and collaborate on rearing offspring), they can coordinate activities like hunting or evading a predator. A tiny minority can even think in abstract terms: Recognising themselves in a mirror, inventing and using tools and constructing complex communication systems. Humans are a member of that minority.

Over many millions of years of evolution, our ancestors started out with a primitive nervous system, then developed a brain. That brain grew in complexity, and new regions and areas grew out of old ones, until now we have the familiar-looking brain we recognise. An important thing to note is that those old, primitive brain regions haven't gone away - they're still a part of our brains today. Evolution has just added new 'modules' to the brain, piling them up, one on top of the other.

Human Brain

So when we look at the structure of the human brain, we see the oldest, simplest structures at the bottom (the spinal cord) and the newest, most complex parts at the top (the frontal lobe). Those old structures still do what they always have (coordinating bodily functions and processing sensory information) and the newer parts do the things we tend to think of as being uniquely human (compassion for others, planning for the future, art, logic, philosophy, language and so on). The cerebral cortex is also the part where most of our consciousness happens.

The brain is also wired up according to that pattern of development. Since the eyes developed long before the cerebral cortex, the part of the brain that processes visual information sits in one of the older parts. There's also a part of the cerebral cortex devoted to processing visual information, but it only does so once the older part of the brain has had its first pass. We know this because there is a condition where people have damage to the visual cortex, and thus are unable to see - but they can somehow still evade obstacles in their path. This means they're still processing visual information, but that information isn't being passed through to the conscious mind.

This is important, because it seems that there's another part of the brain, separate from the conscious mind, that makes decisions.

That's what researchers see in experiments. Neuro-scientists have a very useful tool called functional Magnetic Resonance Imaging (fMRI) which allows them to look at a brain as it's working. They're able to plot out the parts of the brain which are busy by literally seeing which bits light up on the screen while the test subject performs a task.

"I like the pretty lights"

When a test subject is given a choice to make, the first part of the brain to light up is the limbic system. This is a group of components of the brain that form part of the "brain-stem" - a very old part of the brain, just above the spinal cord. This is a part of the brain known to be associated with emotion and processing sensory information (also where the famous "fight-or-flight" reaction lives). Once the subject has made the decision, the reasoning and creative parts of the brain light up, as they start to explain how they arrived at that decision.

So what does that tell us?

It strongly implies that it's our primitive mammalian (or even reptillian) parts that are in charge of making decisions. The 'higher' brain functions are then tasked with rationalising those decisions after they've already been made.

Let's think about that for a little while. It means that the little ferret-like thing living inside you (the legacy of your ancestor from hundreds of millions of years ago) is the one in charge - making your decisions and running your life. It's making those decisions based on simple emotional responses to sensory information, and its primitive little analysis of the world it's living in. The big, clever, human part of you is pretty much along for the ride - making up the story of your life after it happened. That's kinda scary, isn't it?

Who's the boss? This thing.

I said at the beginning of this post that I found this understanding liberating and useful. What's so liberating about having a rodent in the driver's seat of your life?

It's this: I'm no longer bound by my own irrational decisions. I'm able to recognise (sometimes with difficulty) that the choices I've made about my life haven't always been the best ones. How could they be? How can my inner weasel possibly comprehend the complexity of modern human life? If I found that I've made a bad decision along the way, I can go back and revisit it: re-evaluate the story I told myself about it, and try to come up with a better choice based on the real facts of the matter.

I picture myself taking my inner hamster out of his little wheel, giving him a little saucer of things to eat, and explaining to him why his decision was wrong. I give him a bunch of new facts that he probably didn't consider first time around. I show him some mental pictures of how things could have been if he'd acted differently. When we agree on what to do next, I put him back in his little wheel, and get on with it.

My limbic system

I believe that recognising the fact that your own decisions may have been bad, no matter how rational they seemed at the time, is an important revelation. Whenever possible, I try to have that little bonding moment with my Paleomammalian brain before I do anything foolish. I'd suggest that you try that too.

I've gone on about this for far too long already. But I'd like to close with one thing to keep in mind: when making a potentially important decision, try to ask yourself "What would a marmot do?"

Facebook Foolery

Yesterday a Facebook friend of mine posted a status update that got me thinking. I haven't asked his/her permission to reproduce it here, so I won't mention names unless that person decides to identify themselves in the comments.

The Status update was as follows:

"Scientists have discovered yet another link their evolutionary chain: a couple of supposedly several-million-years-old skeletons of "humanoids" that resemble orangutans. Has it occurred to any of those brilliant scholars that those really ARE orangutans?? Hello?"

Without going into too much detail, this person is intelligent, creative, well educated and has an interest in the sciences. How, then, could someone like that be so completely wrong in every detail?

Before I delve into that question, let's first look at why it's wrong.

Given the timing of the post, I'm assuming that it refers to the recently announced discovery of two skeletons belonging to what is being called Australopithicus Sediba - a supposedly previously undiscovered hominid species native to the area surrounding Johannesburg, South Africa (my home - one of the reasons I'm particularly interested in it).

Australopithicus Sediba

As with any proposed new species, particularly those that are claimed to be part of the human ancestral line, there's a considerable scientific controversy about it. This is a normal part of the scientific process: whenever a new discovery is made and a claim put forward as to its place in the scheme of things, it falls on those discoverers to defend their argument from the scrutiny it will receive from the rest of the scientific community. If they're successful in doing so, their new idea will eventually become part of the scientific consensus.

Questions usually raised in cases like this are things like "Is this really a new species?", "Is it really as old as it seems to be?", "Does it really represent a species that is ancestral to Homo Sapiens, or is it only a cousin?" and so on. You may recall the back and forth we've seen over the discovery of "Homo Floresiensis" several years ago. The questions in that debate haven't yet been finally settled, and it may be several more years before they are. The same will likely be true of Australopithicus Sediba as well. John Hawks has written an excellent overview of the controversy surrounding it.

Okay, so that's the background, let's look at the actual claims in the status update:

"Scientists have discovered yet another link their evolutionary chain"

Describing the taxonomical classification of various species as a "chain" shows a pretty clear misunderstanding of how evolution works, and particularly the notion of common descent. For this reason, scientists almost never describe it as such anymore, and seldom, if ever, use the term "missing link" to describe new species either. Simply because those analogies aren't very useful or descriptive. You're far more likely to hear scientists referring to "branches" or "twigs" on the "Tree of life", because that imagery more closely resembles the actual structure of phylogeny. That doesn't stop tabloid newspapers from using the term "missing link" at every available opportunity... but if we haven't learned by now not to trust the mainstream and tabloid media for science news, we are truly lost.

Tree of Life

"...a couple of supposedly several-million-years-old..."

"Several" is an interesting choice of words here. The paper clearly states that the skeletons are less than 2 million years old - between 1.78 and 1.95 million, to be precise. That's not to say that those dates are subject to possible revision, but nobody is claiming right now that they're any older than that. Why implicitly inflate the age?

"...skeletons of "humanoids"..."

The correct term here is "hominid". "Humanoid" is a term used in science fiction to describe species closely resembling humans, but who don't necessarily have any biological relation to us. "Hominid" is a term used in paleoanthropology to describe a subset of ape species that are human-like, including Homo Sapiens - us.

"...that resemble orangutans..."

This is an even stranger choice of words. Why orangutan? Why not gorilla or chimpanzee?

Let's look at a little background in ape phylogeny. Today there are two subfamilies under the family of the "Great Apes" (Hominidae): Pongo (orangutans) and Homininae (gorillas, chimpanzees and humans). That means we're all pretty closely related. But it doesn't mean we're equally closely related to each other. The common ancestor between the Pongo subfamily and the Homininae subfamily lived a lot longer ago than the various common ancestors of the different species within the Homininae subfamily. That means orangutans are our most distant relatives within this family.

Ape Phylogeny

The subfamily Homininae is itself divided into two tribes: Gorillini (gorillas) and Hominini (chimpanzees and humans). That means that within that subfamily, gorillas are our most distant ancestor.

In turn, the tribe Hominini is divided into two subtribes: Panina (common chimpanzees and bonobos) and Hominina (all the different species of humans). Whether or not Australopithecus Sediba is indeed a new species, there is no doubt that it does fall within the Hominina subtribe, which makes it a human species. Which means that it most closely resembles other human species. It less closely resembles chimpanzees. And even less closely resembles gorillas. And even less closely resembles orangutans.

So why choose orangutans to compare it to? I don't get it.

"Has it occurred to any of those brilliant scholars..."

A scholar is a specialist in the humanities: art, history, philosophy. These people are not scholars, they are scientists. Describing a scientist as a 'scholar' is a subtle way of undermining their credibility.

"...that those really ARE orangutans?"

Although I can't read the minds of the scientists involved, I'm pretty certain that this thought has occurred to them. In fact, it's not necessary to be a scientist to make that determination, we can all do it right here together.

Here is the skeleton of Australopithicus Sediba:

The Malapa Skeletons

Here is a skeleton of an orangutan:

Orangutan

They certainly bear a striking resemblance - as do the skeletons of all the great apes. But they are clearly not the same. Even an untrained eye can see the clear differences between them.

Which brings me back to my original question: why would someone say something like this?

I suspect the answer is twofold:

First, the person is very religious (probably a Young-Earth Creationist) and therefore has a vested ideological interest in refuting the claims of paleoanthropologists.

Second, given that, I'm guessing the person relies on a combination of mainstream media (which is incompetent) and Christian publications (which have the same ideological bias, and are also incompetent) for their information.

I think it's pretty sad, really. A combination of selection and confirmation biases have conspired to make this person make a fool of themselves on the Internet. Unfortunately it's not the first time this has happened to someone, and it won't be the last.