Chapter 13: All But Human

• Introduction
• Science is empirical: based on observation.
• It is difficult to "prove" that something is true, instead often times you eliminate alternatives.
• Well known facts can have exception: Newton vs. quantum physics.
• Are human beings intelligent because their brains are different from other animals or because the human brain is larger?
• Differences
• Most of the human brain is the same as other animals
• Cell Types
• Voon Economo neurons - only occur in humans gorillas chimps and bonobos.
• Occur in areas that are active during social interaction.
• Local Circuits
• Broca's and Wernicke's areas.
• "Double-wide" brain cells.
• Connectivity
• Our brains appear to form synapses more readily than other animals.
• Protein thrombospondin.
• Neurons have longer dendrites and have more synapses than apes.
• Human brain is 3 times the size of a chimp brain, but it does not have 3 times as many neurons.
• Recent Genes
• FOXP2
• 200,000 years old.  
• Appears to be language related.
• Microcephalin 
• 50,000 years old
• Regulates brain size
• ASPM
• 10,000 years old
• Involved with microcephaly - reduced brain size.
• Brain Shape
• Area 10
• Involved in higher brain functions.
• Could be larger than expected.
• Others claim it is the correct size for a 1350cc brain.
• From Quantity to Quality
• Where does language come from?
• Why do humans have it, but no other animal seems to?
• Some theorize that humans have a special language module in the brain.
• Others argue that it is size - human beings have much larger (400%) brains than chimps, etc.
• For the time being, neither argument can be conclusively proven as more likely.
• From Brain Advances to Cognitive Advances
• The gap
• Big brains arrive 100,000 years ago
• Real cultural changes start at roughly 20,000 years ago
• Why the gap?
• Critical mass theory
• A critical population is needed to create and pass on knowledge.
• From Cognition to Language
• Observation is that the cortex is already set up to reason in terms of grammars.
• Then the existing structures can be easily used to deal with languages.
• Rather than trying to create a new structure just to deal with language.
• Learning Curve
• There is a large gulf between human style communication (complex) 
• And animal style communication (relatively simple).
• Theory that as a cortical circuit is lengthened, the grammars it can recognize become more complex.
• From Speaking to Writing
• Written language skills are among the most difficult cognitive skills that humans display.
• Unlike spoken language, reading & writing cannot be expected to manifest spontaneously.
• Lack of evidence of reading & writing could have been because of a lack of population 
• 30,000 years ago Europe had a population of around 5,000.
• Why did the Boskops die out?
• Massive difficulty with childbirth (larger heads).
• Means a smaller population
• Smaller population means no critical mass.