Someone on Twitter found a 1986 interview with Pac-Man character designer Toru Iwatani where it was stated that Pac-Man is "a human being":
IWATANI: Well, there's not much entertainment in a game of eating, so we decided to create enemies to inject a little excitement and tension. The player had to fight the enemies to get the food. And each of the enemies has its own character. The enemies are four little ghost-shaped monsters, each of them a different color–blue, yellow, pink, and red. I used four different colors mostly to please the women who play–I thought they would like the pretty colors.
To give the game some tension, I wanted the monsters to surround Pac Man at some stage of the gang. But I felt it would be too stressful for a human being like Pac Man to be continually surrounded and hunted down. So I created the monsters' invasions to come in waves. They'd attack and then they'd retreat. As time went by they would regroup, attack, and disperse again. It seemed more natural than having constant attack.
Then there was the design of the spirit (kokoro), or the energy forces of Pac Man. If you've played the game, you know that Pac Man had some ammunition of his own. If he eats an energizer at one of the four corners of the screen, he can retaliate by eating the enemy. This gives Pac Man the opportunity to be the hunter as well as the hunted.
INTERVIEWER: What was the most difficult part of designing the game?
IWATANI: The algorithm for the four ghosts who are the enemies of the Pac Man–getting all the movements lined up correctly. It was tricky because the monster movements are quite complex. This is the heart of the game. I wanted each ghostly enemy to have a specific character and its own particular movements, so they weren't all just chasing after Pac Man in single file, which would have been tiresome and flat. One of them, the red one called Blinky, did chase directly after Pac Man. The second ghost is positioned at a point a few dots in front of Pac Man's mouth. That is his position. If Pac Man is in the center then Monster A and Monster B are equidistant from him, but each moves independently, almost "sandwiching" him. The other ghosts move more at random. That way they get closer to Pac Man in a natural way.
When a human being is constantly under attack like this, he becomes discouraged. So we developed the wave-patterned attack–attack then disperse; as time goes by the ghosts regroup and attack again. Gradually the peaks and valleys in the curve of the wave become less pronounced so that the ghosts attack more frequently.
