Harlow showed that in rhesus monkeys perceptual learning sets for many categories can be formed simultaneously, and the color perception learning set is formed more rapidly than the form or size perception learning set (3). It has not been made clear, however, whether these sets are independent of each other, and whether the color perception set, for example, is effective only for the color category and not for others.
The purpose of the present experiment is to investigate the transfer between color and form, and that between form and size in perception learning set. These sets are formed successively and have seemingly no common cue.
S_s : Two Japanese monkeys (Macaca Fuscatus) (RON and CHAKO) and one Formosa monkey (Macaca Cyclopis) (CHETA).
Apparatus : Modified WGTA for paired discrimination.
Stimulus : Eight stimulus boards (7.5 cm×7.5 cm) for each category. Eight color stimuli are so arranged that one color is for one stimulus. Form stimuli are shown in Fig. 1 (white on black). Size stimuli are black squares of eight different sizes on white board. Categories other than the cue are invariable. Procedure : From 8 stimuli, 28 different pairs are possible for each category and the reversal of positive-negative role in the pairs makes 56 problems. When training exceeds 56 problems, these 56 problems are repeated. Eight ten-trial positional sequences are used. Four problems are presented each day.
Training begins with 168 (56×3) color discrimination problems, which is followed further by 112 (56×2) form-, 56 color-, 56 form-, and 56 size-discrimination problems. These 448 problems are divided as shown in Table 1 for the convenience of the description of the results.
The instrumental response required in the experiment is same all through the experiment.
Results : Shown in Table 2. The formation of the form discrimination set (F₁-F₄) began at chance level ; however, it improves faster than the preceding color set formation (C₁-C₆). The color set did not transfer perceptually to the form set. The rapid formation of the form set suggests the existence of the other sort of facilitating factors, which is not, however, the sameness of the instrumental response. The size set began at the higher level and its improvement was not faster than the color or form set. The preceding set formations transferred positively and perceptually to the following size set formation.