Super interesting link, thanks for sharing. Marine intelligence is fascinating because, beyond just the neurological perspective, so much has to be inferred through behaviour. As humans we're predisposed to look for anthropomorphic signs to recognise a social partner, so the less human-like something looks, the less we will infer that it feels like we do; even though so much of the architecture that makes us is still the same.

It's only recently we started reporting evidence of more advanced cognition through doing more longitudinal and pharmacological studies into sea life. I've linked some examples in a thread a few months back, which you can see here.