This volume reports investigations covering a period of three years, dealing with the fundamental facts and forces in learning. -- preface.

Reprint of the 1932 edition.

Introduction -- The influence of the repetition of a situation -- The influence of the repetition of a connection without belonging -- The influence of the repetition of a connection with belonging -- The influence of the impressiveness of the first term upon the gain in strength from a given number of occurrences of the connection -- The influence of the distribution of the occurrences of a connection upon its strength --The polarity of mental connections -- The influence of repetition of a series upon the omission of its intermediate terms -- The influence of the after-effects of a connection -- The influence of the after-effects of a connection when oppurtunities to repeat or revive it or any equivalent or substitute for it are excluded -- The influence of rewards and punishments -- The physiological basis of the strengthening of connections by three after-effects -- Readiness, identifiability, and availibility -- The influence of mmental systems -- Desires, purposes, interests, and motives -- Associative shifting and the conditional reflex -- Minor experiments, comments, and suggestions for further investigation -- Adverse evidence and arguments -- Appendixes.