[fwip]

Just a quibble - children learn object permanence at around six months of age. Also, I don't think the jury is quite in on cows - I've seen papers that argue both ways.

One way we could quantify cow happiness, if we were interested in doing so, is in the amount of stress hormones they produce.

[b112]

This reminds me of a story, where a utility had buried power lines near a farmer's grazing field. These were milk cows, and he didn't know why but they had stopped giving milk, and seemed sickly.

Vets couldn't figure it out. They seemed healthy otherwise.

Turned out that for some reason, the cows were constantly being low-level shocked.

Most people I know, prefer to think of eating an animal that was happy until it was killed, and killed mercifully. It could be an important metric, much like grass-fed or some other property.