SynapticNulship

It’s certainly not new to propose recursion as a key element of the human mind—for instance Douglas Hofstadter has been writing about that since the 1970s.

nested recursion

Michael C. Corballis, a former professor of psychology, came out with a new book this year called The Recursive Mind. It explains his specific theory that I will attempt to outline here.

The Recursive Mind

As I understand it, his theory is composed of these parts:

1. The ability of the human mind to generate concepts recursively is what causes the main differences between homo sapiens and other animals.
2. A Chomskian internal language is the basis for all external languages and other recursive abilities. (See this blog post by Corballis for a summary of an internal language as a universal grammar).
3. External languages evolved on top of the recursive abilities primarily for storytelling and social cohesion.
4. External languages started with gestures, and most likely were followed by mouth clicking languages before vocal languages emerged.

You’ll notice that toolmaking and other modern human capabilities are not mentioned in my list there. That is because those are considered to be evolved/developed after the recursive mind appeared and after rudimentary language based on recursion appeared. The author talks about how the ability to build multi-part tools and using tools to make tools probably depends on recursion, but he thinks that came after a certain amount of language development.

recursive construction

A host of abilities might be dependent on recursive thinking, even things we take for granted like story telling. Planning, talking about the future, and making fictional stories all might be dependent on recursive processing.

primitive gestures

Corballis has been doing research on gestures for a long time. By gestures we mean both bodily and facial. It certainly sounds plausible based on the evidence we have that gestures might have been the first real external language. Corballis claims that the discovery of mirror neurons added support for this theory. A primate watching another one perform an action has mental processing similar to actually doing the same action itself. Corballis proposes here and in previous works that sign language with grammar and syntax appeared long before it was mainly replaced with the cultural development of vocal speech.

(As a related aside, see this TED video about the power of communication via dance.)

Conclusion and a Warning

The Sierpinski Triangle

It’s certainly an interesting theory, and I can buy that recursion is part of, if not the single key element, of a general protocol in the mind. Even if we forget the linguistic aspect, the power of recursion seems to be a fundamental ability of the mind at some level.

Fortunately, as a computer programmer (amongst my many roles), I don’t have to limit myself as academics love to do when talking about the sole “language of mind” or the single important algorithm or type of algorithm needed to turn an pre-human mind into a human mind. I can easily imagine lots of protocols (I think that is a better word than “language” for system communications) at all kinds of arbitrary levels, in many relationships to each other. I think it’s kind of silly to assume there’s only one universal protocol and that it underlies all the others. Even in a digital computer (of which most computers are), the only “general” protocol that underlies all others is the fact that information is represented with binary. You have to go to another level above that to describe anything else, and it won’t be completely general. And a digital computer is much simpler than the brain. But what about the fundamental difference between humans and other animals? Well, again, recursion seems to be a good candidate, but it wouldn’t surprise me if it’s only one of several intertwined informational abilities that make human minds different than others.

Postscript

Based on comments on Science 2.0, I may have made this summary too thin. So why exactly would recursion be of interest to single out? Isn’t it just one of many run-of-the-mill features of information processing? Basically, Corballis proposes this:

Generative functions require recursiveness. Episodic memory requires generative functions. Episodic memory may be unique to humans. Planning future events and making fictional stories requires episodic memory. Communication of future events and storytelling–which in turn requires ways to communicate the time component–may have co-evolved with human external language abilities.

References

[1] Corballis, M.C. The Recursive Mind. Princeton University Press, 2011.

Image Credits

Inception Chair by Vivian Chiu
book cover, Princeton University Press
Derek O’ Reilly
Rhys Davenport (found via Sean Williams)
Sierpinski Triangle, public domain

I just published version 2 of my Enactive Interface Perception essay over on Science 2.0.

It’s now called “Enactive Interface Perception and Affordances”.

You spend a large portion of your time staring at heads of people. But have you wondered how they evolved? Harvard scientist Daniel Lieberman, Professor of Human Evolutionary Biology, has been studying human head evolution, particularly the unique features relative to other animals.

I attended his lecture at Harvard tonight, “Heads Up! How and Why the Amazing Human Head Evolved to Be the Way It Is,” which is timed with the release of his new book The Evolution of the Human Head.

First, Lieberman took off his shoes. It just snowed again in Cambridge and he doesn’t like wearing his boots (or maybe he has some kind of Mr. Rogers complex).

Second, Lieberman talks about how the functions and ontogeny of the human head would boggle any engineer if they had to make something like that. For instance, it’s hard to imagine how to design and implement a pea-sized robot that grows into a cantaloupe-sized robot while maintaining survival functionality the entire time.

If robot heads could grow.

Of course, it’s not an entirely fair comparison since natural products aren’t engineered, but the point is that the head seems overwhelmingly complex to us.

Integration

Not surprisingly (to me), Lieberman’s basic recipe for head development is integration. You can view the development of a body part as a series of interactions with atomic parts, which lie at various levels of granularity. For instance, you have proteins, cells, tissues, organs, etc. All the parts constantly adjust to each other, so as to maintain the overall system.

Lieberman uses the concept of skeletal capsules, but he warns us that it’s just a hypothesis called the functional matrix hypothesis. Some of his past research was to find correlations between various bone structure sizes in mice, and apparently he found a wicked lot of correlations.

Integration continues all through ontogeny.

He showed two photos of characters from Harry Potter, and claimed that it showed how each person’s nose matches their face. However, it wasn’t very convincing, especially his calling Daniel Radcliffe’s head narrow when it looks really wide to me, like as wide as Elijah Wood’s.

Harry Potter, wide in cranium, narrow in patience.

What would have been better is an example of what would happen without the integration between subsystems—would somebody have a nose covering up their eyes or something?

Harry Potter with development error.

Or the nose would just fall off and run away?

Nooooooooooooooooose!

Of course, the environment is also involved in ontogeny—later in the presentation he described an experiment he did with hyraxes, in which they found that if the babies chewed softer food, they had smaller teeth as adults.

Hyrax Potter.

Anyway, the way this complex head integration relates to evolution is that it gives evolution something very hackable. It enables evolution to cause major changes in growth from minor tweaks.

The rest of the talk was a quick tour of the evolutionary history of human heads.

Human Head Uniqueness

So what are the aforementioned unusual characteristics of human heads? Well, the brain case is different, our neck comes out of the bottom of our head, we have vertical foreheads, visible eye whites, external nose, no snout, small mouths, small canine teeth, big ear holes, etc.

Your head is remarkably unusual.

Unfortunately, Lieberman does not have a good theory for one of the human head’s unique features: the chin. It’s still a mystery.

The Chin: Science's Next Challenge

Image credits:

Robot head: Rodimuspower
Hyrax: Nitzan Cohen Kafri

Cross-posted with Science 2.0.

Humans can only be conscious of one task at a time.

Tasks that user experience and interaction designers are concerned with are usually relatively complex.  Tasks that require you to think about them.  Generally this means you are aware of what you are doing.  Later on you might be so familiar with a standard task that you don’t have to be aware of it, but at first you have to learn it.  You might think this means consciousness is only needed for learning tasks.  However, in many cases not being aware during a task can result in failure–because your consciousness is required to handle new problems.

And yet it seems like we are multitasking all the time.  I routinely have 3-4 computers and 5-6 monitors with dozens of applications running at work, typing a line of code while somebody asks me a question.  In this photo you can see me multitasking while teleoperating a robot (this was my old office in 2008 with only 4 monitors…)

But I’m not consciously attentive of all that simultaneously.  I just switch between them quickly.  Typing while listening to someone talk is difficult without accidental cross-pollination, but it is easy if you have a buffer of words/code already in your head and you’re just unconsciously typing it while your attention is now focused on the completely different context of listening to a human talk.

Task switching and flipping between conscious and unconscious control happens so quickly and effortlessly that it’s hard to believe that there is really just one task getting “processed” at a time.  For some strange people, like computer engineers, this makes perfect sense, since that’s how basic CPUs work–one simple instruction at a time, millions of times per second.  Multiple programs can run on serial computers because the computer keeps all the programs in memory, and then hops between them very fast.  A little bit of this program, then a little bit of that program, and so on.

As Missy Cummings, a former Navy pilot and human factors researcher, puts it: “In complex problem solving tasks, humans are serial processors in that they can only solve a single complex problem or task at a time, and while they can rapidly switch between tasks, any sequence of tasks requiring complex cognition will form a queue…” [1].

For this reason, Cummings has warned people of the dangers of cell phone use while driving.  However, you can in fact drive while using a cell phone.  You can do lots of things while driving.  Have you ever been spaced out while driving (or walking) and found yourself transported to another location?  Who was driving in the interim?  You have trained yourself to drive enough that your mind can actually do it unconsciously.  However, if there is a problem or an unexpected event you will be alerted to that consciously–or you will not be alert and crash into something or someone.

But, since we can get close to multitasking–by switching quickly and letting learned tasks run unconsciously–why would user interaction designers be worried about multitasking?

Well first, as we already mentioned, often you need to be snapped out of auto-pilot to handle a new or emergency situation.  In some situations, not being conscious most of the time on the primary task can be very dangerous.  Do you want your ambulance driver to be playing GTA IV and polishing his/her nails on the way to rescue you (from your texting-related auto accident)?

Second, the more you multitask, generally the less efficient you become at all the tasks.  Personally, I have also found that if the tasks are in very different contexts, the context switching itself uses a lot of energy.

As Dave Crenshaw said (quote via Janna DeVylder) [2]:

When most people refer to multitasking, they are really talking about switchtasking. No matter how they do it, switching rapidly between two things is just not very efficient or effective.

And see DeVylder’s blog post “Save Me From Myself: Designing for Multitasking” for a good intro to the design considerations of multitasking.

    
Why is it Serial?

I think that serial consciousness evolved in animals because they are situated and embodied.  It wouldn’t work to have two conscious threads trying to drive one body in different directions.  Multiple threads have to share resources.  Having one thread conscious at a time gets closer to guaranteeing that multiple threads don’t conflict.  I would expect that when the system breaks down it would be very confused and might hurt itself.

Note: If the term “thread” is too computerese for your liking, then perhaps you can think of trains.  Consciousness is like a train station with only one track.  The metaphor breaks down pretty quickly, but hopefully that will get us on the same page.

Certainly there is parallelism in the brain–indeed that is touted as one of the brain’s great advantages.  The parallelism is also very different from most of our digital computers (for those who like to compare brains to computers).  But cell networks are at a much lower level in the skyscraper of the mind.  

What about behaviors?  Somewhere in the middle levels of the mental skyscraper, we do have parallel behaviors, but they are automatic.  The autonomic nervous system (ANS) keeps everything running–breathing, heart rate, sweating, digestion, sexual arousal, etc.  You can be conscious about some of these behaviors, such as breathing, but you don’t need to do that.  And I would venture that if you could, and tried, to turn off the ANS and control all those functions consciously at the same time, you would die quickly.

It may be trite but it’s worth invoking a manager hierarchy metaphor: The top manager is consciousness, and as you go lower, things become more automatic and less directly controllable by the higher up manager.  And this top manager is not director George Lucas, who supposedly micro-manages the tiniest details in his movies.  This manager is more like the other George Lucas, the one who oversees a vast empire–he doesn’t care about details (fast-forward to 08:15 in the video below for the relevant discussion).