Hi! I'm Tim Tyler and this is a video about cultural evolution and its
portrayal in the evolution textbooks.
So first of all here are some evolution textbooks.
I'm going to start by describing my own view of the subject.
I think that cultural evolution is part of evolution by definition.
The definition of evolution just says that it's about heritable
traits - the changes in heritable traits in a population over time
And it doesn't say how the inheritance takes place Whether or not it
is by nucleic acids or by cultural transmission Or by some other
means of transmitting information down the generations.
So, by that definition, circumcision is transmitted down the
generations and so counts as evolutionary change. Wearing kilts, for
example, is also transmitted down the generations - and changes in
kilt styles would be a class of evolutionary change - and similarly
with spoken language for example. Changes in spoken language are
also a type of evolutionary change - according to the definition of
evolution.
Now the textbooks on evolution don't seem to make much mention of
cultural change. They describe changes in DNA-based creatures but
they fail to mention changes in televisions or computers or designs
of automobiles or designs of musical instruments, there's a whole
section of what I regard as the biosphere that is excluded from
evolutionary explanations by conventional descriptions of evolution.
So let's see how the theory is portrayed in the textbooks.
To start off here is Evolutionary Biology by Douglas Futayama
one of the well-known textbooks on evolution.
This particular book makes no mention of cultural change there is no
coverage of cultural evolution at all it presents a standard
definition of evolution which includes cultural evolution by
definition. There is no coverage in the book of cultural evolution.
it completely ignores the whole subject. it doesn't attempt to
describe the controversy over this issue, it just completely ignores
it - a huge blind spot in the book. So, that's that one.
The second one has some more interesting coverage. Evolution by Matt
Ridley another well known evolutionary textbook.
this book differs in its definition of evolution. it presents the
standard definition and then it raises three exceptions that it
thinks are irregularities - and so don't count as evolutionary
change:
The first is changes in population which are due to development so
changes over an individual's lifetime don't count as evolution it
says which seems relatively uncontroversial to me: changes over an
individual's lifespan don't result in any heritable changes in the
population - that is agreed by most parties not to count as
evolution.
The second one that it mentions is changes in an ecosystem over time
- so, if species A and species B, say species A is 10% of the
population and species B is 90% of the population,and then that
changes so that species A 70% and species B is 30%, it claims that
doesn't count as evolution because there is no change within each
individual species, but...
Then there is a third exception - and that's cultural evolution. It
says that cultural evolution doesn't count as evolution, and the
explanation reads as follows:
Changes that take place in human politics, economics, history,
technology and even scientific theories are sometimes
loosely described as evolutionary. In this sense "evolutionary"
means mainly that there has been change over time - and perhaps not
in a preordained direction.
human ideas and institutions can sometimes spit during their history
- but their history does not have such a clear-cut branching
tree-like structure as does the history of life. Change and
splitting provide two of the main themes in evolutionary theory.
So here Mark Ridley presents his justification for ignoring cultural
evolution in the rest of the book but his justification - based on
the supposed lack of branching structure within cultural evolution -
is just a - kind-of - a basic fallacy within cultural evolution. if
you exclude phenomena that don't have a branching treelike structure
then that immediately writes off most of the bacterial root the tree
of life - because there there is horizontal transmission of
heritable information just as there is in cultural evolution.
That point is made by Daniel Dennett for example, in Freedom Evolves
which I will briefly quote from:
It is sometimes claimed, erroneously, that this cultural
transmission, being between genetically unrelated individuals, shows
that human culture cannot be interpreted as an evolutionary
phenomenon governed by the principals of neo-Darwinian theory. In
fact, as we have just seen, horizontal transmission of good design
elements between unrelated individuals is recognized as an important
feature of evolution of early (single-celled) life, with a growing
list of proven instances, a centerpiece, not an embarrassment, of
contemporary evolutionary biology. [p.146]
...and Daniel precedes that by a discussion of symbiotic
relationships and how they indicate transmission of heritable
information horizontally between existing organisms rather than down
the generations to generate a branching tree-like structure.
So: this is just a fallacy. The idea the idea that cultural
evolution displays horizontal transmission and biological evolution
doesn't is wrong: biological evolution itself displays horizontal
transmission in an almost identical manner to cultural evolution so,
the whole basis of Mark Ridley's dismissal of cultural evolution
just seems wrong to me.
Also the whole idea of setting up a nice neat definition of
evolution - and then listing exceptional cases - just goes against
the grain from the perspective of the philosophy of biology - you
want evolution to be a neat clearly-defined category not some
category and then a list of exceptional cases that don't count.
so, his three cases, he excludes change during development which is
fair enough, that is not inherited that is not part of evolution
anyway, but his other cases: change in an ecosystem due to changing
distributions of species that counts as evolution - and cultural
change that counts as evolution too in my book.
So, anyway, at least he presents a coherent reason for ignoring
cultural evolution - even though that reason is wrong, basically.
So that is Mark Ridley - and then lastly, Monroe
Strickberger another evolutionary textbook. Here, this textbook
is about 13 years old, but actually gives some coverage of
cultural evolution: this textbook radically disagrees with
the other textbooks that I have cited in that it classes cultural
evolution as evolution - and there's a nice neat paragraph which
expresses the sentiment:
In short, humans have two unique hereditary systems. One
is the genetic system that transfers biological information from
biological parent to offspring in the form of genes and chromosomes.
The other is the extragenetic system that transfers cultural
information from speaker to listener, from writer to reader, from
performer to spectator, and forms our cultural heritage.
Both systems are informational in that they produce their effects by
instruction, the biological systems through the information embodied
in DNA via the coding properties of these cellular macro-molecules,
the cultural system through social interactions coded in
language and custom and embodied in records and traditions.
- Monroe Strickberger, Evolution (1996).
So, amazingly, a textbook about evolution that actually include
something about cultural evolution! It doesn't include much coverage,
it's got that paragraph, and then there's another short paragraph
which sounds as though it's going to lead onto something interesting
it says:
The fact that human culture has as its source a biological
foundation and that culture and biology arise from informational
systems that evolve over time, has prompted various writers to
suggest that general laws cover both society and nature each sharing
similar evolutionary mechanisms - especially that of
natural selection.
- Monroe Strickberger, Evolution (1996).
And yes, that is exactly the idea, but then unfortunately it goes on
for several pages about social Darwinism and about
sociobiology - and doesn't really address the topic that it
originally sounded like it was going to talk about.
So, although there is some coverage, hardly any. It is all
confined to a short chapter at the end entitled "culture and the
control of human evolution" does talk about genetic engineering a
bit, but still extremely meagre coverage right at the end
of the book, but at least provides an exception to the rule of
textbooks completely ignoring cultural evolution -
actually inculdes cultural evolution within evolutionary theory
which is a big breakthrough as far as I'm concerned as far as
the conventional academic establishment of evolution goes.
So, good score there, however poor coverage - only a few
pages really. so that's how I think the textbooks stack up regarding
cultural evolution.
As far as I can see all the textbooks need a complete rewrite to
deal with the issue. it is not something that is unique to humans it
is embedded in all animal evolution, practically, there is evidence
that small birds exhibit cultural evolution and insects as well - and
culture and genes coevolve so you can't really understand evolution
without considering cultural evolution.
So, yes, major rewrites seem to be required to me.
So that's how I think the textbooks currently stack up.