only when they detect predators in the environment. Animals often repro-
duce at an older age when environmental resources are scarce.
Apart from the impact of obvious risk factors such as alcohol or nicotine
abuse of the mother during pregnancy, environmental influences on the
developing human brain have not been conclusively demonstrated. For
example, in the brains of people with extensive academic education there are
more bushy dendrites, but this can be either the cause or the result of their
academic success (Kalat, 2016, p. 127). Musicians have thicker gray matter in
several areas (pp. 127–8). However, this is not surprising as learning means the
adding of new synaptic connections (Squire & Kandel, 1999, pp. 129–55).
Recent neuroscientific research yielded the surprising insight that new neu-
rons are produced in the adult hippocampus (neurogenesis), whichfits in well
with the role of this area in memory—although the exact role of the new
neurons in not yet clear (Welberg, 2013). The plasticity of the brain is also
witnessed by its adaptation to damage (Kalat, 2016, pp. 136–42). For example,
after damage to one half of the motor cortex the healthy part can take
over tasks, at least after a sustained learning process. A much-discussed
phenomenon is the appearance of“phantom limbs”after amputation, where
neighboring parts of the somatosensory cortex become blended so that touch
to the face, for example, is also felt in a missing hand.
We have different personalities that are shaped by genetic and develop-
mental factors. Our personality traits ultimately reflect structural differences
in our brains, even if these differences are far more complex than popular
theories like“brainedness”suggest. If you and I buy exactly the same com-
puter model and put them side by side after a year we willfind that they
behave differently in many respects: one will be slower than the other, tuned to
solve different specific tasks, and contain an entirely different set of“memor-
ies.”Yet a professional will have no difficulty understanding the behavior of
both machines based on a set of general principles. Although every analogy is
incomplete, we can think about human differences in a similar way. Based on
our knowledge of how the human brain is structured in general we can
understand how brains differ from each other. Appreciating individual differ-
ences is thus not an argument against studying the brain but an important
motivation to do so.
(2) Second, we come to the topic of how brains change in history. For
Biblical Studies, the question can be put like this: are our brains not so
different from the brains of ancient people that any reliance on contemporary
neuroscience research is irrelevant for the study of the Bible? Since we have
already discussed related topics from the perspective of evolution in the previous
chapters, we can limit ourselves to a few remarks at this point. Let us start
with an extension of our discussion about individual development. If we agree
that comparing the brains of two people living today is a meaningful project
The Human Brain: A Guided Tour 59