Skinner's Laws.

B.F Skinner was the founder of behavioral pyschology and this article contains some laws he discovered. I think they're interesting in two ways when talking about game design.

  1. Applied to the player
  2. Applied to AI

When applying these rules to the player we can use them as rules of thumb for when to give out rewards. For in an RPG when to give out loot, or how to layer and structure the rewards. When applying the laws to AI we can use the rules for state transitions, controlling when a creature goes aggressive or shoots off a special move. These laws could even be used for more developed AI systems like Steve Grand's Creatures game or Lionhead's Black and White.

Skinner came up with a lot of laws. This list isn't complete if you're interested in finding out more, check out his book; The Behavior of Organisms.

The Law of Threshold

The intensity of a stimulus must reach or exceed a certain critical value (called the threshold) in order to elicit a response.

Imagine a deer hearing the player's footstep through the forest. If the footsteps are far away it may ignore them, if they're over a certain threshold it may dart away. Stimulus followed by response.

The Law of Latency

An interval of time (called the latency) elapses between the beginning of the stimulus and the beginning of the response.

The stronger the stimulus the shorter the latency.

The Law of Magnitude of the Response

The magnitude of the response is function of the intensity of the stimulus.

Note: Some responses are all or nothing.

Imagine attacking a monster, if you hit for < 10 HP it just attacks back. Hit over 10 and it heals itself and launches a full power counter attack.

The Law of After-Discharge

The response may persist for some time after the cessation of the stimulus.

The deer continues running away until it feels safe, not until it can no longer hear footsteps.

The Law of Temporal Summation

Prolongation of stimulus or repetitive presentation with certain limiting rates has the same effect as increasing the intensity.

Note: Summation is often restricted to near-threshold values of the intensity.

If the player is stomping around near the deer but not quite enough to make it run, the continued presence of the stomping sound will make the deer run, even if it's below the threshold.

The Law of the Refactory Phase

Immediately after elicitation the strength of some reflexes exists at a low, perhaps zero, value. It returns to it's former state during subsequent inactivity.

If a creature performs an action according to a stimulus, it's less likely to take the action again until a certain time passes.

The Law of Reflex Fatigue

The strength of a reflex declines during repeated elicitation and returns to it's former value during subsequent inactivity.

A player finding an awesome sword in a barrel has a joyful response. If he continues to search nearby barrels and each has a even more awesome sword, the joyful response is less and less powerful.

Note: When fatigue takes place quickly, recovery is slow.

Certain reflexes to loud sound may fatigue fairly quickly and remain at zero for considerable periods. The time required to build up the original strength through inactivity may be of the order of months or years.

Adaptation and fatigue are distinguished only by duration to reset.

The Law of Facilitation

The strength of the reflex may be increased through the presentation of a second stimulus that which does not itself elicit the response.

A loud sound is often given as an a example of a facilitating reflex.

The Law of Inhibition

The strength of a reflex may be decreased through presentation of a second stimulus which has no other relation to the effector involved.

Maybe a driver, angry at traffic, becomes a little less angry if a kitten comes out of the glove box.


Hopefully that's fired your imagination up a little! There are further laws but they become more concerned with conditioning - the kind of Pavlov's dog type of experiments.