Neanderdad was confused. His 3-year-old daughter held up a sippy cup with a built-in straw. He had just conveyed to her that she must drink in the kitchen. Yet she was still upset. She waved it under his thick brow, as if to better reveal to him specific technical details that he did not understand.

“This one doesn’t leak, Daddy?! Mommy said I can take it with me to the living room.”The child spoke well. Too well, Neaderdad thought, for one so young. And too well for him to cleave to his stated rule. Was there some nuance to the rules he and his mate had set? He decided to repeat what he knew, in hopes the problem would go away. “Drink only in kitchen.”

The child would obey. The dissonance that rattled his low-cubic-centimeter cranium would stop. He could, once again, focus on what he did best. Provide resources. Food. Shelter. He had an idea where a herd of mammoths might be grazing. If he could just get back to his tools. — nytimes.com