Knowledge of Result (KoR) Experiment in Psychology: Learning and Performance Insights

Knowledge of Result (KoR) Experiment is important concept in psychology which is used to study learning and performance.


Statement of problem for Knowledge of Result (KoR)

To study the effect of degree of Knowledge of results on performance with the help of the line drawing experiment.

Introduction of Knowledge of Result (KoR)

Law of effects

This law states that responses followed by satisfying outcomes are more likely to be repeated, while responses followed by unpleasant or unsatisfying outcomes are less likely to be repeated.

As originally proposed by Edward L. Thorndike, the law of effect stated that if a response R produces a satisfying state of affairs (or a positive reinforcer), then an association is formed between R and the stimuli S present at the time R was made. As a result of this S–R association, R occurs whenever the organism encounters S. This part of the law of effect was the foundation of S–R theories of learning.

Originally, Thorndike also proposed that the presentation of an aversive or annoying consequence serves to weaken S–R associations, with the consequence that responding becomes suppressed. He later revised the law to include only the response-strengthening effect of reinforcement; the original version of the law was called the strong law of effect, and the revised version was known as the weak law of effect.

For example, in a simple operant conditioning experiment, if a rat receives a food reward (satisfying outcome) after pressing a lever, it is more likely to press the lever again in the future. This behavior is reinforced by the positive outcome of receiving food. In contrast if the rat receives an electric shock (unpleasant outcome) after pressing the lever, it is less likely to press the lever again in the future, as the behavior is punished by the negative outcome.

Knowledge of Result (KoR)

American psychological Association explained Knowledge of Result (KoR) as verbalized (or verbalizable) information about the outcome of a response in relation to the goal.

Learning theory suggests that a learner profits most from immediate availability of this information (e.g., about the accuracy of responses on a test or the speed and accuracy of a movement or an action sequence). Although knowledge of results is essential for guiding acquisition, too much feedback can prevent the individual from forming an internal model of what is correct behavior.

Original Experiment: Thorndike (1931)

Thorndike (1931) and Trowbridge and Cason (1932) studies are historical documents, giving origin to the KR/ KoR investigation. They used the drawing lines task to investigate the KR precision in four conditions (no KR, nonsense KR, qualitative KR in a right-wrong way, and quantitative KR about the length of the drawn lines).

The authors concluded that the nature of the information received by the subject produces some learning effects. (Law of Information).

The general plan of the experiment described by Thorndike was as follows:
“The S was seated, blindfolded, at a table opposite the E, and in front of a drawing board, along the left handed edge of which a strip of veneer, about 2 in. wide, had been fastened in such a way that a large sheet of cross- section paper (16 X 21 in.) could be slipped between it and the board and fastened to the board by means of two or three carpet tacks. The strip veneer served as a fixed starting edge for all the lines. The cross- section paper itself was so ruled, in pencil, as to make it possible for the experimenter to tell readily the length of any line drawn from the strip as a zero point. The S was instructed to draw lines of given length, starting always from the strip of veneer at the left, and to wait after each line until hearing the score called, before drawing the next line. He was required to draw each line with one continuous, quick movement”

S was instructed to draw a 3-, 4-, 5-, or 6- inch line and the E said “Right” when S’s line was with ⅛ inch of the correct length.

Hypothesis Knowledge of Result (KoR)

Knowledge of result will have positive effect on the performance of the subject.

Variables in  Knowledge of Result (KoR)

  • IV- Conditions of knowledge of result
  • DV- Performance of drawing the line across the conditions
  • CV- Length of standard line, Trials taken in each condition
  • EV- Past knowledge, Motivation, Personality, Mood and

Material in Knowledge of Result (KoR)

  • Blind- folding goggles
  • 30 cm. scale
  • A- 4 size blank papers
  • Wooden screen
  • Data sheet
  • Treatment of results
  • Stationery
  • Graph papers

Plan of Knowledge of Result (KoR) Experiment

Trial No.Condition ICondition IICondition IIICondition IV
No FeedbackFeedback      (Right/ Wrong)Feedback   (Shorter/ Longer)Exact Feedback

Procedure of Knowledge of Result (KoR) Experiment

  • The experimenter checked on the required material; then the subject was called inside the cubicle.
  • Rapport should be established.
  • Due instructions were given by clarifying the doubts.
  • Subject was comfortably seated blindfolded.
  • Plan of the experiment was strictly followed throughout the experiment.
  • Introspective report was taken at the end.

Instructions of Knowledge of Result (KoR) Experiment

  • This is a very interesting experiment.
  • Here you see two dots, one on the left and the other on the right.
  • I will place the scale to connect the two dots.
  • You are supposed to place the pencil point on the left dot and then close your eyes.
  • When I ask you to start, draw a line with yours eyes closed along the scale without stopping.
  • Stop when you feel you have reached the dot on the right.
  • You have to keep your eyes closed throughout the experiment.

Precautions of Knowledge of Result (KoR) Experiment

  • Blindfold the subject properly for every trial throughout the four conditions.
  • For every trial the starting point should be variable.
  • No extraneous cues to be given to the subject during performance of drawing the lines (like feeling the surface, verbal motivation, etc.).
  • No retracing of the line is allowed by the subject while drawing.

Discussion of Knowledge of Result (KoR) Experiment

  • The purpose of the experiment was…….
  • Present the Results
  • Comparison with classical experiment
  • Connect with Introspective Report

Conclusion of Knowledge of Result (KoR) Experiment

The hypothesis stating that “Knowledge of result will have positive effect on the performance of the subject.” was accepted / rejected.


  • Bandura, A. (1977). Social learning theory. Prentice-Hall.
  • Schmidt, R. A., & Wrisberg, C. A. (2008). Motor learning and performance: A situation-based learning approach. Human Kinetics.
  • Thorndike, E. L. (1911). Animal intelligence: Experimental studies. Macmillan.
  • Winstein, C. J., & Schmidt, R. A. (1990). Reduced frequency of knowledge of results enhances motor skill learning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 16(4), 677-691.

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