The Brain Shrinking Except for the Frontal Lobe: It’s Growing

PIC: Camazine (CC)

PIC: Camazine (CC)

Scientific studies indicate that while the brain overall is shrinking, the frontal lobe – that part of the brain responsible for communication, planning and executive function, among other things – is growing. No one knows why for certain, but there are a lot of theories. Could it be related to the birth of reading and writing? Also interesting is an apparent increase in sexual dimorphism:

Via EvoAnth:

The 7,000 years or so these endocasts cover is also the period writing was invented and spread around the world; until many countries have almost universal literacy rates. In other words, as reading and writing becomes more important the region of the brain needed for it becomes larger, despite the fact the rest of the brain is shrinking. It’s a “no duh” question; but could there be a link? The researchers think so1, but it is worth noting the frontal lobe is also linked to planning and memory.

The team also found that there had been an increase in the differences between the sexes (sexual dimorphism) over this time. In the earliest skulls they examined there was only ~150 ml difference between males and females. In present day populations this shot up to almost 200 ml1. This is particularly interesting given the course sexual dimorphism of the body has taken over human evolution. In our early ancestors it was massive, with men being much taller than women. Over time it decreased; but not seems to be increasing again5. In other words it’s followed the same sort of path as brain size, reversing course quite recently.

Keep reading at EvoAnth.

5 Comments on "The Brain Shrinking Except for the Frontal Lobe: It’s Growing"

  1. BuzzCoastin | Mar 13, 2014 at 7:03 pm |

    over 50% of the brain
    runs 99% of the bodies functions

    wee need all that frontal lobe brain power
    to mastcate, fornicate and deficate primarily
    and play in the devils workshop otherwise

  2. Annnd yet again they don’t consider how the biochemistry we build our brains with has changed dramatically in that time with the advent of agriculture. As if it doesn’t matter what you build the most sensitive and complex organ this side of the milky way out of on a subcellular level….

    The very slight increase in the frontal lobe is negligible considering that it was brocha’s area, and the growth correlated well with the advent of written/spoken language in the form we use today. Even just meditating briefly each day leads to increases in certain areas in no time at all. As taxi drivers become more experienced they’ve even been found to have larger parts of the brain that deal with mapping the environment. Nothing new there really.

    People need to look into Tony Wright’s research with this data in mind.

  3. Reuben_the_Red | Mar 14, 2014 at 12:38 pm |

    In “Galapagos,” Kurt Vonnegut suggested that it was humans’ Big Brains that were humans’ main problem, the ability to hold too many contradictory ideas simultaneously. Also makes childbirth tricky.

    • Matt Staggs | Mar 14, 2014 at 3:03 pm |

      Great one. I have a signed copy of that. A battered, used paperback. It has Vonnegut’s signature just under the “Paperback Hut” two-for-one stamp. I chose it to send to him because I heard that he didn’t sign books anymore, and thought that the best chance of me getting him to do it anyway would be to appeal to his ironic sense of humor. Apparently it worked.

      • Reuben_the_Red | Mar 14, 2014 at 3:53 pm |

        Now Kurt’s in heaven, signing books from Jesus’ paperback collection.

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