Chris Chatham of Developing Intelligence blog wrote an excellent summary of the controversy over dolphin intelligence and adds his own thoughts on the matter, with which I agree:
In conclusion, there are countless reasons to doubt that dolphins are "dumber than goldfish," or indeed that popular musings about dolphin intelligence have been inaccurate. Of course, as Cognitive Daily points out, it is clear that they don't have human-level intelligence - whatever that may mean. On the other hand, Manger has developed a new theory about the evolution of the dolphin brain; unfortunately, any extrapolation from neuroanatomy to cognition is still highly theoretical, particularly in the case of dolphins, whose brains are so drastically different from our own. Therefore, given the state of neuroscience, judgments of dolphin intellectual powers must more heavily weigh behavioral work (however flawed) than arguments from evolutionary data and cellular neuroscience such as Manger's.
Read the whole thing.
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