I know who you are... and your attentional state!
Pigs can distinguish between other pigs, including closely related individuals, again showing high intelligence. Mothers recognise their litter from sound alone and piglets can differentiate between known and unknown pigs based on urine samples alone (32). Like dogs, pigs can differentiate between humans, using body size as well as aspects of facial characteristics and sounds, and to a lesser degree, smells (where humans are concerned), as cues.
It isn’t surprising that dogs and horses, bred to interact with people, can distinguish between human attentional states; but pigs have been raised to be killed at a young age for meat and they too, prefer and choose people who show them attentiveness over those who don’t. Also, pigs can understand a human pointing, eg to find a food reward (32).