Speech as a product of sexual selection

[Wolfhnd]

I was watch a documentary recently on human evolution and one of the scientist proposed that speech was likely a product of sexual selection. His theory rest on the idea that the utility of speech for activities like cooperative hunting seem dubious in it's early stages. He went on to explain that human speech more closely resembles bird song than the sounds animals make in cooperative defense or predation. By extension the suggestion is that music or rhythmic vocalizations precede coherent sentence structure. The utility then becomes attracting mates, soothing infants, and reducing aggression.

[Travis Hallet]

Speech is something created by humans to communicate. All other spices have a form of speech, it just isn't as sophisticated as ours. Especially apes, they have a variety of noises that mean different things. Also you can teach an ape to speak in sign language. Even dolphins can communicate with eachother.

 

And here is a question for you to ponder about this topic. If speech were part of evolution, then how could the non-speaker know that the person that could speak actually spoke?

[Wolfhnd]

This is not the kind of reply I had hoped for because it places a burden on me to explain cultural evolution. The idea that language was created with purpose is as silly as saying that the cells in your body know what their purpose is. Our cells go about their business absolutely ignorant of purpose. How does a cell know what it's purpose is if it has no consciousness? Yet all the individual cells in our brain self organize without purpose in an evolutionary process to allow for what we call consciousness.

 

Children learn to speak before they know what the words they are speaking mean. Do the words children use have purpose? Does a child point at a cat and speak the word cat for some purpose? It's not until a fluent individual provides the appropriate feed back that the association becomes fixed. More importantly to the discussion at hand why does soft humming or a lullabye calm an infant? It's not speech but it is certainly vocal communication. The child does not understand the purpose nor does the parent understand what is being communicated both just respond to stimuli.

 

Words are memes and they are selected for in the cultural environment. There are words that are created by intelligent design but often they are not selected for and fall out of usage. The kind of hocus pocus that sophisticated philosophy uses to say words are not memes is a kind of self delusion.

 

The human mind looks for agency in everything the same way a deer jumps at the sound of a falling branch. The natural assumption that language was "created" with purpose is not evident any more than there is a predator behind every falling branch. We are simple wired to think that way. This is often referred to as the Darwinian inversion of reason. We see purpose in the world around us because we "feel" motive in our thought process and project it onto the world. The rationale exists not in the world but in the observer.

 

Culture is the latest expression of an evolutionary continuum. Language is just one of many adaptive tools that have evolved over time. The different between genes and memes is that memes are not confined by physical existence. Just as we have domesticated animals over time we have domesticated language. It may be a bit confusing to see but it is still evolution by selection not "natural" selection but not entirely conscious either.

Edited May 25, 2015 by Wolfhnd

[CharonY]

If only taking what is described in OP the evidence seems to be rather weak to me. From the limited information it seems that the only argument is that for some reasons bird song is supposedly more similar to speech than other forms of vocal communication, which does not seem to be very conclusive (e.g. how are they more similar). This all does not even address the point of what other potential factors are related to speech evolution. It does not need to be one or the other, it could have been a multi-purpose tool from the get-go.

 

Even birds have non-mating related calls and in a number of mammalian species vocalization is used as a warning signal (again, mating unrelated). In other apes vocalization serves quite a number of purposes, including emotional expression that are not all related to mating. It is not implausible that it is one piece of the puzzle, but how large this piece is and how it relates to other elements would require much more work and I imagine it would be very tricky to get that data (as we are limited in what we could do experiment-wise).

 

That being said, the idea is not new, Darwin already proposed that things like culture and potentially language arose from sexual selection. From the area of linguistics there are actually arguments against this as there it is typically assumed that flexibility and information transfer (a whole subset of this branch deals with so-called "honest" communication) is one of the inherent elements of human language. However, under sexual selection, exaggerated displays of particular traits are selected for (including for instance loudness and/or specific elements or complexity of mating calls that apparently can be used by the female to gauge suitability of her partner). This would be a counter-mechanism to flexible communication that conveys a plethora of information. Also, under these conditions, males would be the main communicators.

[Wolfhnd]

As always a very well thought out reply. CharonY

 

Here is an article with more depth.

 

Human speech and birdsong: Communication and the social brain

 

http://www.pnas.org/content/100/17/9645.full

 

I was brief in the OP because these ideas are constantly popping up and there isn't time to cover them all. I suppose the genus is not in coming up with plausible theories but in testing them.

[MonDie]

That being said, the idea is not new, Darwin already proposed that things like culture and potentially language arose from sexual selection. From the area of linguistics there are actually arguments against this as there it is typically assumed that flexibility and information transfer (a whole subset of this branch deals with so-called "honest" communication) is one of the inherent elements of human language. However, under sexual selection, exaggerated displays of particular traits are selected for (including for instance loudness and/or specific elements or complexity of mating calls that apparently can be used by the female to gauge suitability of her partner). This would be a counter-mechanism to flexible communication that conveys a plethora of information. Also, under these conditions, males would be the main communicators.

 

Boastful displays aren't the extent of it since birds exhibit behavioral isolation stemming from song differences. As Wolfhnd's link explains, some Aves young use social cues to learn their distinctive singing style.

We humans certainly use our language for exaggerated displays, but it's more in the content of our communications. I recall a finding that when men lie, it's usually to protect their own self image, whereas when women lie, it's often to make others feel better.

Why do we enjoy music anyway? Women tend to find deeper voices more sexually appealing.

 

Sex, Lies and fMRI--Gender Differences in Neural Basis of Deception

Psychological studies claim that both men and women are equally prone to try to manage their appearance %5B2%5D. However, men are particularly likely to lie about their abilities and to exaggerate their personal characteristics and past experiences %5B4%5D, %5B5%5D, whereas women may lie more to promote intimacy, and their lies are intended to make other people feel better about themselves (e.g., %5B6%5D).

[CharonY]

This does affect potential dimorphisms in language use, yet does not explain the development of language as a consequence of sexual selection. The similarities in development (again, outside of selection) between human and birds is well noted, but also exaggerated as birds traditionally have been used as models for human speech development (as you should not dissect infants). Again, one thing is mechanism, and a second is the historic (i.e. evolutionary) development.

 

My guess is (almost as always) that due to the flexibility of the tool it touches on many selective forces, which may include sexual selection. To ascertain that there is one main path is, in absence of experimental evidence, very speculative at best.

[MonDie]

It's my mistake. The post became a tangent.

Ironically, I only provided a supporting example for you. Lying isn't related to establishing meanings with others, but to misusing meanings that were previously established. which perhaps degrades them. Yet lying is what sexual selection seems to have pushed for.

Edited May 27, 2015 by MonDie

[Wolfhnd]

What original caught my attention was how necessarily speculative these type of theories are. Scientific speculation is not only healthy it is an essential part of the art of discovery. It becomes a question of motivation. If scientists speculate out of natural curiosity that is acceptable but I think that there is a tendency to speculate as an appeal for acceptance by the audience. The desire to be interesting to others is a natural part of our social predispositions. I think we need to stop censoring "idle" curiosity to remove the temptation to present it disguised as theory.

[CharonY]

To be fair, all speculations outside of publications are generally considered to be "idle" speculations. And I am not sure that many come up with them to specifically pander to the public.It is just that some sell better to media and the public than others and hence, become more prominent. There are many more pet theories that are not likely to emerge from drawers or from conversations without a significant amount of alcohol.

In some cases these ideas may inspire someone to follow up with something serious, resulting in a publication and moving it to the realm of discovery, though.