Most tests are based on the use of language and they've all been developed by humans for humans.
How can we compare the intelligence of a chimp to that of a capuchin monkey to that of a goat or a pig?
What is intelligence?
Howard Gardner talks about multiple forms of intelligence in his book "Frame of Mind, The Theory of Multiple Intelligences" published in 1983. His work, which is in direct line with that of John Dewey, has had considerable influence on methods of education in the United States.
According to Gardner there are nine forms of intelligence:
* naturalist - the ability to discriminate between living entities
* musical - the ability to discern sounds, pitch and rythm
* logical - the ability to calculate
* existential - the ability to reflect on life
* interpersonal - the ability to understand others
* kinesthetic - the ability to master various physical skills
* linguistic - the ability to use a language to communicate
* intra-personal - the ability to understand oneself
* spatial - the ability to think in three-dimensions
This list is definitely applicable to most monkeys and apes. All have the ability to recognize objects and other individuals in their environment. They use different sounds or calls to warn their troops about predators, among other things. They are cunning enough to be able to deceive another member of the group to their advantage or plan and enforce coups to take over power. This alone implies that they have some understanding of their own volition and desires but also are smart enough to read others' emotions and intentions. They are certainly very physically dexterous and see the world in three-dimensions. Even though their natural way of communicating cannot be called "language", they do have the proven ability to communicate by gestures, looks, sounds and some have been trained to communicate with humans by learning to use pictograms (Koko), sign language, or lexigrams (Kanzi).
Now, in an effort to level the plain field for intelligence testing, two computer scientists, Dr Hernandez-Orallo and Dr Dowe are working at designing a universal test that will not be based on spoken language. Instead they will use the Kolmogorov complexity theory as their basis.
Personally, I cannot wait to see the results on monkeys and apes.
For fun, you can check out the following videos.
Kanzi, the Bonobo
Kanzi plays with his son Teco
Koko learns a new sign
And if you want to test your own intelligence, you can play games at the Posit Science website.