Read It's a Jungle in There: How Competition and Cooperation in the Brain Shape the Mind for Free Online Page A

mainly keep to themselves and mainly marry in-county. As a result, they enjoy less genetic variation than other, more open communities. As a further result, they have unusual traits. Due to a recessive allele shared by two members of the founders of this colony in the mid-1700s, a disproportionately large number of Amish have Ellis-van Creveld syndrome. 15 Individuals with this syndrome are shorter than usual, have unusually broad hands and faces, and have malformed wrists and an extra finger—a syndrome known as
polydactyly
. Ellis-van Creveld syndrome is traceable to two of the small number of individuals who first settled in the area that the Amish now inhabit.
    The founder effect has psychological analogues. One is imprinting. Here, in the case of ducklings, the sight of a figure that may plausibly pass for Mama Duck is latched onto by recent hatchlings. They follow this figure even if she, he, or it is not their parent, provided it’s the first reasonable facsimile of a parental figure they encounter. This phenomenon was made famous by the Austrian ethologist Konrad Lorenz, who, it happens, worked with greylag geese rather than ducklings, though the phenomenon works with eitherspecies. 16 Imprinting is analogous to the founder effect in that primary experience has extraordinary impact.
    Two other psychological analogues of the founder effect can be mentioned. One is the tendency of words that are learned first to be read aloud at exceptionally high speeds—much higher than would be expected based solely on how often they are repeated. This has been shown both in tasks that require reading of printed words and in tasks that require naming of pictured objects. 17
    The other psychological analogue of the founder effect is speaking a language with an accent reflecting the dialect spoken where you were raised. In my case, I was raised in Philadelphia, so I speak with a Philly accent. When I say “noodle,” I can’t help but say “neeodle.” When I say “legal,” I can’t help but say “liggle.” I can try very hard to say these words without my Philly twang, but it’s nearly impossible for me to do so. The same phenomenon occurs for people who speak English with a Russian accent, for people who speak Hebrew with a German accent, and so on. The fact that accents are so hard to shed—extensive voice coaching is usually required—attests to the founder effect for speech. 18
Punctuated Equilibrium
    Besides the founder effect, another phenomenon of special interest from evolutionary biology is punctuated equilibrium. This is a relatively sudden change in the rate of evolutionary change. The term
punctuated equilibrium
refers to the fact that fossil records have shown that, in evolution, there have been periods of relative stasis or equilibrium punctuated by periods of very rapid change. 19
    Punctuated equilibrium is important here because in mental development there are similar surges. One occurs around the age of 18 months, when in healthy human toddlers there is an explosion of language. From 18 months to 24 months, toddlers roughly double their vocabularies, from about 1,000 words to about 2,000 words. 20
    On a faster time scale, mental states also tend to change quickly after periods of seeming quiescence. You don’t
gradually
see a shape, and you don’t
gradually
learn a fact. As is true of evolutionary states, mental states are punctuated. Minds jump from state to state, from not understanding to understanding, from not seeing a solution to seeing one. If there is a stream of consciousness, as William James suggested, the stream doesn’t flow continuously. 21 Rather, what you think of from moment to moment is a series of discrete realizations.
Niche Opportunities
    The third phenomenon of evolutionary biology of interest here is the existence of
niche opportunities
. When niche opportunities arise, a species occupies a new habitat and survives within it with a low population density for a long time. Then, if