It's just speculation on my part, assuming the idea put forward by the study is true. Like if humans were to start living underwater, I don't think there would

It's just speculation on my part, assuming the idea put forward by the study is true. Like if humans were to start living underwater, I don't think there would be evolutionary pressure on us to lose our intelligence. More speculation: maybe it's not ocean vs. land itself, but the process of moving from one to the other. The smartest ocean-goers have the best chance at thriving on land; the smartest land-goers have the best chance at thriving in the ocean.