Brain lateralisation is another indirect marker for intelligence. What it indicates more directly is how specialised a brain is by the function of each area of it. These effects are the driver behind humans being almost alone among mammals in the degree of preference for the use of our right hand (at least 90% across all our cultures), foot or paw.
For sperm whales this same phenomenon seems to manifest as an extreme preference of viewing eye. As with us, it seems to be to the right. I ask for open discussion below from any who have witnessed the phenomenon.