[nospecinterests]

How does the intelligence of an animal effect how that living creature should be treated? For example, do you think it is appropriate to treat a monkey better then one should treat a dog or cat simply because a monkey has a higher mental capacity?

[rlanday]

Isn’t that the basic justification for why we treat humans much differently than other animals? I think this is because we each know we’re capable of suffering and assume other humans are as well, and in the lack of other evidence, assume that animals with brains more similar to humans’ are more capable of suffering than less intelligent animals. I also think this reasoning is a major reason why research into differences in human intelligence between individuals is so controversial.

[nospecinterests]

I think that could be one reason/assumption. Though I think generally humans think that living creatures can all suffer. After that it comes down to acceptability and return.