A | B | C | D | E | F | G | H | I | J | K | L | M | N | O
P | Q | R | S | T | U | V | W | X | Y | Z |

---

KEY : see OPERANDUM.

KEY : Any manipulable object, the movement of which closes or breaks an electrical circuit. In experiments with pigeons, a useful key is a translucent disk at a convenient height on the wall of the experimental box. When the pigeon pecks this disk, a circuit is made or broken. In experiments with rats, a horizontal bar parallel to and approximately inch from the wall of the experimental box can be pressed downward against a light spring to close or break the circuit.

KEY : A hinged plate which produces an electrical pulse when moved is called a key. In experiments with pigeons, a translucent disc at a convenient height on the wall of the experimental box is frequently used as a key. When a pigeon pecks this disc, the movement operates an electrical switch. A spring returns the hinged plate to the unoperated position. In experiments with rats, a horizontal bar, parallel to the wall of the experimental space, closes the switch against the pressure of a light spring.

KEY LIGHT : Light projected upon the translucent pigeon key, used as a stimulus. Lights of different colors or patterns may be used.

KINESIS : (plural. kineses). Undirected movement that depends on stimulus magnitude (as when the random movements of an insect larva increase with light and stop when it reaches the dark).

KINESTHETIC STIMULUS : PROPRIOCEPTIVE

KNEE : A deviation from a smooth curve, often seen in the early acceleration of interval or ratio segments, consisting of a brief period of rapid responding followed more or less abruptly by a compensatory low rate which restores the curve to an extrapolation of the earlier portion. Opposite of bite (q.v.).

KNOWLEDGE OF RESULTS : A kind of feedback, usually verbal, given during human performance in various tasks (e.g., verbal learning, motor skills).

KOR : See KNOWLEDGE OF RESULTS.