Tag Archives: Brains

Personality Is Overt

If the human mind is split to parts that manage overt appearances, and parts that manage covert strategies, which parts do you think more control our personalities? Yup, personalities are closer to overt appearances:

By using composite images rendered from three dimensional (3D) scans of women scoring high and low on health and personality dimensions, we aimed to examine the separate contributions of facial shape, skin texture and viewing angle to the detection of these traits, while controlling for crucial posture variables. After controlling for such cues, participants were able to identify Agreeableness, Neuroticism, and Physical Health. … Information allowing accurate personality identification is largely lateralized to the right side of the face. (more)

Chimpanzees, other primates, and humans produce asymmetrical facial expressions with greater [emotional] expression on the left side of the face (right hemisphere of the brain). (more)

In most animals, left brains tend to manage and initiate actions within the current mode, while right brains watch in the background for patterns and reasons to veto current actions and switch modes. In humans, it seems the current-action-sequencer brain half was recruited to focus more on managing overt rule-following language, decisions, and actions, ready to explain away any apparent rule-violations. The less-introspectively-accessible pattern-recognizing background-watcher brain half, in contrast, was apparently recruited to focus on harder-to-testify-on-and-so-more-easily-covert meaning, opinion, and communication, including art and music. (more)

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Whence Better Brains?

The cover story of the July Scientific American is on brain physics. It persuades me that raw brain hardware was more important than I’d thought in our history.  Here is my current best guess on brain history.

Across diverse species we see strong convergence in brain organization, especially conditional on brain size. Species differ more in their brain hardware components, and their energy sources. For example, primates have innovative cell designs allowing higher neuron density. Given access to such cells, primates could afford to evolve bigger brains, and then bigger pair-bond-based social groups.

Humans found a way to use big primate brains to support big-group far-traveling long-life versions which could access richer energy sources, which in turn supported large energy-hungry brains. Humans found a way to use those huge old social brains to support robust accumulation of culture, which is our main advantage over other primates. This was probably supported by only minor changes in brain organization.

While the brains of smarter humans today may use a better set of long term connections, probably most of their advantage comes from using more energy-intensive brain hardware. So it probably wasn’t until our recent cheap energy era that high IQ humans gained large advantages. The tendency 0f smarter humans to choose lower fertility lowers their advantage today.

Many quotes from that article: Continue reading "Whence Better Brains?" »

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Two-Faced Brains

Although human language allowed egalitarian rules whose uniform enforcement would have greatly reduced the advantages to big-brain conniving, humans had the biggest brains of all to unequally evade such rules. (more)

As with most lying or self-deception, homo hypocritus faces a serious implementation problem: how to keep the lies it tells separate from the “real” beliefs on which it acts. Since brains tend to be liberal with interconnections, there is a real risk of cross-talk between contradictory sets of opinions; lies may infect beliefs, and beliefs may infect lies.

I’ve previously discussed one solution: have the different sets of opinions apply to different topics. For example, hold socially-acceptable opinions on far topics, where the personal consequences of actions tend to be smaller, and keep more realistic opinions on near topics, where such consequences tend to be larger. Yes there’s a risk others may notice that you change opinions without good reason as items move from near to far or far to near, but that may be a relatively small price to pay.

A different solution is to have two distinct processing centers, each highly-connected internally, but with only modest between-center connections. One center would manage a coherent set of lies, while the other managed a coherent set of true beliefs. And in fact real brains have exactly this architecture! Left and right brains are highly connected internally, but only modestly connected to each other. Does the left brain manage a coherent set of overt opinions, while the right brain manages a coherent set of covert opinions? Consider:

  1. In all vertebrates left brains tend to control routine behavior (e.g. feeding) while right brains tend to respond to unusual events (e.g. fight/flight).
  2. Left brains tend to initiate actions, via positive feelings, while right brains tend to inhibit actions, via negative feelings.
  3. Compared to other primates, left vs. right human brains differ a lot more in function.
  4. The left human brain manages language’s literal quotably-overt syntax, vocabulary, and semantics, while the right brain handles language’s less-socially-verifiable tone, accent, metaphor, allegory, and ambiguity.
  5. Split brain patients show that left brains are adept at making up respectable explanations for arbitrary right brain behavior.
  6. Right brains tend to be used more in crafting lies, and they can read subtle emotion clues better.
  7. Left brain damage tends to distort behavior in more obvious and understandable ways.
  8. Left brains emphasize decision-making, fact retrieval, numbers, and careful sequenced acts like throwing, while right brains emphasize art, music, spatial manipulation, and recognizing of shapes, patterns, and faces.

It seems that in most animals, left brains tend to manage and initiate actions within the current mode, while right brains watch in the background for patterns and reasons to veto current actions and switch modes. In humans, it seems the current-action-sequencer brain half was recruited to focus more on managing overt rule-following language, decisions, and actions, ready to explain away any apparent rule-violations. The less-introspectively-accessible pattern-recognizing background-watcher brain half, in contrast, was apparently recruited to focus on harder-to-testify-on-and-so-more-easily-covert meaning, opinion, and communication, including art and music.

I’m not saying that overt vs. covert human beliefs map exactly to human left vs. right brains, any more than socially-useful vs. action-practical beliefs map exactly onto far vs. near beliefs. I’m just suggesting that human brain design took pre-existing animal brain structures, such as near vs. far modes and left vs. right brain splits, and recruited them to the task of managing the uniquely human task of hypocrisy: simultaneously espousing and evading rules. In particular, the left-right brain split become an important tool for minimizing undesirable leakage between the overt rule-following images we present to others, and the cover rule-evading actions and communication which better achieve our real ends.

More quotes:

The left hemisphere is specialized not only for the actual production of speech sounds but also for the imposition of syntactic structure on speech and for much of what is called semantics – comprehension of meaning.  The right hemisphere , on the other hand, doesn’t govern spoken words but seems to be concerned with more subtle aspects of language such as nuances of metaphor, allegory and ambiguity. (Ramachandran, quoted in TMHH p56)

No other [vertebrate] species consistently prefers the same hand for certain skilled actions. … The human brain is distinguished from the brains of the great apes by an extraordinary extent of lateralization of function. (more)

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