Pac-Man Ghost Personalities

The four ghosts from pac-man were:

Blinky (red)
Pinky, (pink)
Inky, (blue)
and
Clyde, (orange)

It is the fact that each of these ghosts exhibits a distinct personality that makes this game so entertaining and playable. Once acquainted with their personalities, it is possible to predict their movements.

Here they are:

Blinky - Chases. Will usually take the shortest route to you, and tends to follow.
Pinky - Ambushes. Tends to take a more roundabout way to pac-man. Deadly.
Inky - Freak. This dude acts strangely. He moves about the board fairly randomly, but sometimes chases when he gets in close.
Clyde - Idiot. Moves randomly. Not much of a threat.

N.B.: The blinky-pinky combination is the most menacing. Watch out for them in the corners.
Next time you play some pac-man, notice that it's usually these 2 that get ya.

These personalities stayed the same through Ms. Pac-Man and Pac Man Jr. Clyde went through two name changes, though, called Sue and Tim in the following two games, respectively.

Some notes on ghost behavior:

Cruise Elroy

Despite the moniker "Speedy", Pinky is not the fastest ghost. All ghosts on all levels move at identical speeds, with one exception. The red ghost ("Shadow", "Blinky") will speed up once a certain number of pellets remain. This phenomenon is known as "Cruise Elroy" mode. Below is a table indicating when Blinky will enter Cruise Elroy mode:

Level     Pellets remaining
1       20
2       30
3-5     40
6-8     50
9+      60


Scatter Mode

The ghosts have an interesting pattern programmed into their movements: occasionally, they will simultaneously cease and desist their pursuit of Pac-Man and return to their respective corners of the maze, entering "scatter mode".

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.
-- Toru Iwatani, creator of Pac-Man

The ghost will enter scatter mode four times for each life on each level. As they exit the ghost house, you can easily see they begin play in scatter mode. Blinky heads for the top right corner, Pinky for the top left, Inky for the bottom right, and Clyde for the bottom left. When the ghosts enter scatter mode is determined by a timer. Generally the first two scatters are the longest in duration, and the third and fourth are about 2/3 as long. Beware Blinky: he can still pursue Pac-Man in scatter mode.


The "Pause" Spot

The "pause" spot is place on the map where the ghosts cannot discover Pac-Man. It exists to the right and up a few spaces from Pac-Man's starting location, inside the crook of the turn. If Pac-Man enters this area from the right while no ghosts can see him, he can safely remain there for up to 18 minutes (when the ghosts reverse direction). This is a good place to park Pac-Man if you need to get a drink or hit the bathroom.


Individual personalities

Both Blinky and Pinky appear to be programmed to pursue Pac-Man directly. Pinky usually makes the opposite turn choice from Blinky when given a chance, and so this duo often can trap your man in a corner. Inky is a wildcard, and given the same situation often makes different choices. Inky definitely appears to be programmed to ambush Pac-Man. One theory is he heads for the end of the tunnel Pac-Man is currently moving down. Clyde moves randomly, and so can be the most frustrating ghost to work with.


Patterns

Patterns are certain movement paths which, if followed exactly, allow Pac-Man to reproducibly clear a certain amount of the board and consume a certain number of blue ghosts / bonus prizes. A web search will quickly provide more patterns than a sane person would want to memorize. Most players consider this boring if not cheating, and eschew patterns.

The first person to ever achieve a perfect game of Pac-Man was Billy Mitchell (in 1999). Billy refused to use patterns. Instead he claimed he had a perfect knowledge of the ghosts behavior:

"First, you’ve got to learn how to control the monsters. See how the red, pink and blue are grouped together? It’s easier to control 2 monsters than 4. ... You actually learn to control the game. As long as you have control of the game, you don’t die."
-Billy Mitchell

Miscellaneous Pac-Man info:

Bonus Prizes

Level     Prize          Point Value
1           Cherry          100
2          Strawberry     300
3-4     Orange          500
5-6     Apple          700
7-8     Grenade     1000
9-10     Spaceship     2000
11-12     Bell          3000
13+         Key          5000

The game ends when you reach the 256th level. This level is divided in half: the left half of the screen displays the regular left half of the maze. The right hand side is composed of random ASCII-style characters and colors. There has never been evidence of anyone successfully completing this level.

The game of Pac-Man is always in one of three modes: Scatter, Chase, or Frightened.
The current mode governs the behavior of all four ghosts.
(When you see a ghost reverse³ direction, a mode change has occurred.)

Scatter and Chase mode alternate seven times before settling on Chase.
(four scatterings and four chases---reset on every new life or level)

During Scatter, the ghosts retreat toward their home corners.

During Chase, a ghost's behavior depends on its color:

RED, the Prosecutor, chases Pac-Man directly, targeting his current position.

PINK, the Ambusher, aims a small distance ahead¹ of Pac-Man.

BLUE, the Capricious, targets the reflection of Blinky's position across Pinky's target¹.

ORANGE, the Maunder, approaches Pac-Man when far from him, and flees toward the corner (just as in Scatter mode) when near to the hero.

During Frightened, ghosts are vulnerable to being eaten by Pac-Man and they flee randomly².

    .---.                                 ______
   ;     \      _        _        _      |__ __ |
  :    .'      / \      / \      / \     |Þ )Þ )|
  :   :        | |      | |      | |     |      |
  :    '.      \_/      \_/      \_/     |      |
   :     /                               |      |
    '---'                                |/\/\/\|

---

For information about
how ghosts decide how to reach their target,
the variation of speeds and timings throughout levels,
how ghosts decide when to leave the house,
and more about this game than you thought there was,
read The Pac-Man Dossier.

1. When Pac-Man goes up, there is a bug which causes Pinky (and thus Inky) to shift its target from where it "should" be.

2. A pseudorandom number generator chooses a random memory location from which the necessary bits are read.

3. This is the last footnote because it's not related to Pac-Man. Why is it "When a ghost reverses direction" but "When you see a ghost reverse direction"? Or should it be "When you see a ghost reverses direction" or include a preposition or otherwise be rephrased?
locke baron says re Pac-Man Ghost Personalities: To answer 3, it's a mood issue. "when a ghost reverses direction" is in the indicative mood, while "when you see a ghost reverse direction" is subjunctive. Weird, yes. It's often clearer in other languages - darn English :P
DonJaime says re Pac-Man Ghost Personalities: re note 3: it's not that 'reverse' is in the subjunctive. Rather, it doesn't have a subject to agree with ('the ghost' is the object of 'see') at all. I think it's an infinitive used as an object complement, but don't quote me on that without the don't quote me on that disclaimer.
raincomplex says that makes sense---"I saw Alice kill Bob" "I will hear the band play music" "I would love to know you hate squirrels"
DonJaime says "I would love to know you hate squirrels" is different, because the entire clause 'you hate squirrels' is the object.