rationalskepticism.org

jez9999 wrote:So what is a common measure of intelligence, then? I think mathematics is actually a really good measure of raw intelligence, being as it's so abstract and usually far-removed from real-world scenarios; an animal's traditional environment is unlikely to give them an inherent advantage in this area.

No mathematics is a specific application of intelligence. That would be akin to testing the intelligence difference between you and I by using "knowledge of behavioral psychology" as the measure of intelligence - assuming that you have no formal qualifications in the area, then the test would conclusively demonstrate that I was far more intelligent than you. But obviously this would be an incredibly unfair measure of intelligence and wouldn't tell us anything useful except for the fact that I have studied a subject you haven't.

The tests of intelligence vary according to exactly what we're looking for (e.g. differences or similarities between species), what species we're using (e.g. human vs animal, animal vs animal), what kind of intelligence we're looking for (e.g. abstract thought or memory), and so on. We can measure abstract thought by using stimulus equivalence tests, which basically assess how well an individual can form concepts given certain variables and we can compare exactly where they excel and fail. One of the standard measures for intelligence is to place the subject in an experimental setup where the conditions change, without signal, at certain times throughout the session - we then measure how quickly the choice responses of the subjects adjust as the conditions change, and we can quantify this with a specific measure called "sensitivity to reinforcement". We then have a raw score that can be compared across species.

jez9999 wrote:As for language skills, I'm saying that I struggle to see how our ability to use language could evolve over small, incremental steps. I don't see why no other species - in the history of the world - would have developed language as advanced as ours if that were something that evolution was even rarely capable of.

Well I think the problem is with how you're thinking about it. We haven't evolved the complex language that you see us using, we've evolved to be capable of using language - that is, understanding abstract symbols and make sounds with our vocal chords. The complexity of language, like grammar, metaphors, humour, etc, is largely a product of the cultural effects on language. We don't evolve these advanced aspects of language through evolution, we create them ourselves through learning and experience. In other words, it's like saying you can't understand how tool-use could evolve because building rockets is so amazing. We didn't evolve to build rockets, we evolved the capability to manipulate things with our hands.

The reason no other species has reached this advanced stage of language is because they don't have all of the right conditions that we have. One of the key features for the development of language as advanced as ours is bipedalism and opposable thumbs - this automatically rules out large sections of the animal kingdom. Then we need advanced control of our vocal chords, and a sufficiently intelligent brain to process language. Once you start looking at all these factors that make language possible, you start to realise why it isn't too common.. It's also very energy intensive, so effective communication would actually be a disadvantage for a number of animals because they aren't puny bald apes, and they can easily defend themselves and catch their food without having a chat about it.

This isn't to say that animals can't learn language just because they don't meet the same criteria that we do (and research suggests that a lot of animals can pick up complicated aspects of language fairly easily), but it just means that it's unlikely to be learnt without external guidance, i.e. us teaching it to them.