There’s recently been something of an argument between Michael Egnor and Jeffrey Shallit, over whether animals can think abstractly.
Egnor’s most recent post is here:
and it contains (near the beginning) links back to he earlier posts on the topic. Shallit’s most recent post is here:
and the last line links to his earlier post in the dispute.
There is a simple answer to the question. Humans are animals, and humans can think abstractly. But that misses the point. The argument was really about non-human animals.
For myself, I don’t really have an answer. The problem that I see, is that we do not have a clear definition of “abstract thinking” that we could attempt to apply to animals. There’s a good chance that Egnor and Shallit are talking past one another, using incompatible meanings of “abstract thinking.”