The purpose of this paper is to examine what factors affect the rate of activation spreading in memory networks. In the experiment, subjects learned a list of syllable pairs. Each critical stimulus item was paired with two alternative response items, which were different in the strength of association and/or the strength of trace of the response items. Which of the two alternatives subjects recalled first was affected only by the strength of the association. It was concluded that the strength of the link from the node affects the rate of spreading activation from the node, but the strength of the node does not.
MM, who lost her sight binocularly due to keratomalacia 10 months after birth, received optical iridectomy on her right eye at the age of 12. Preoperatively, her right eye had only light perception. Immediately after the operation, her vision improved little, if at all. It was found that she could distinguish more light, but couldn't see either color or form. She had conspicuous nystagmus, and could not fixate continuously on the light projected on a dark screen, and often failed to indicate the direction from where the light had entered her right eye, except when it entered in front of the left side. Prior to facilitating her vision-sign system activity, her activity of touch-sign system was intensively examined. In particular, the extent (roughness or density) of differentiation in various kinds of attribute (length, size, 2-dimensional figure and solid figure) was investigated during a period of about 2 months after the operation.
This study was undertaken to find out (1) what operations one had to carry out beforehand for successful actual drawing of the geometric figures, and (2) what kinds of tasks were useful to get such operations. We set two experiments so that Sub. T (CA 5:6, PIQ 52, VIQ 112, PQ 67) might draw an oblique line and a triangle successfully. The results showed that the operation we originally named "tentative drawing", a trial drawing with a forefinger or eye movement, was requisite before actual drawing with the general instrument like a pen. It was then suggested that "tentative drawing" enabled him to anticipate the result of actual drawing as well as to avoid the error drawing in advance. In addition, this "tentative drawing" was acquired through the "ball task" which required to draw the slope on which a ball would roll down into the glass. This fact suggested that the manner of figure drawing was come into his mind and then established in advance by imaging the movement of a rolling ball along the slope in the "ball task".
The present goldfish shuttlebox experiments were conducted to test the background (contextual) conditioning hypothesis, which assumes that conditioned background (contextual) stimuli generate a shuttling response and facilitate Sidman avoidance learning. In Experiment I, goldfish were preexposed to the US and/or training background stimuli. In both response and US measures, US preexposure, irrespective of the background stimuli, facilitated avoidance learning in the early stage. In Experiment II, goldfish were preexposed to the US and/or the training context (apparatus). In the response measure, preexposure to either the US or the training context deteriorated avoidance learning in the later stage. In the US measure, however, later stage avoidance learning was deteriorated by preexposure to the training context alone (i.e., regardless of US preexposure). In addition, the US measure indicated that preexposure to both US and training context facilitated early stage and deteriorated later stage avoidance learning. These results can be interpreted in terms of both associative and motivational effects of US preexposure; background (contextual) conditioning and learned helplessness.
The present experiment was conducted to ascertain the phenomenon of Pavlovian conditioned inhibition in rats in a licking conditioned suppression situation, and to examine the efficacy of the Rescorla-Wagner model in describing the conditioning processes. In the first phase, conditioned excitation was established to the stimulus A by the A-US pairings. Thereafter, the stimulus A was simultaneously presented with another neutral stimulus X without being paired with the US. In this phase, the groups received different treatments concerning the excitatory tendency of A: Group P received continued presentations of A-US pairings while the explicitly unpaired presentations of the A and US were given in Group U. Subsequent retardation test revealed that Group P had developed greater inhibitory tendency to X than Group U. The results were discussed in terms of the computer simulations of the Rescorla-Wagner model with special reference to the salience of the stimulus X.