Apparent movement in tridimensional space

The space-time relationships satisfying Korte’s third law of apparent movement were studied in three experiments. The results generally confirm and extend Corbin’s conclusion that apparent movement is not a projection-level phenomenon, but one involving spatial constancy, i.e., some representation of tridimensional space. Between situations in which the stimuli were retinally matched, the time interval necessary, for apparent movement varied w~th their phenomenal separation, whether the latter was determined by the distance of stimuli from the O, deviation of sttmuli from the frontal plane, or illusory slant of the stimulus plane produced by a perspective gradient.     

Audiovisual integration in perception of real words

Three experiments follow up on Easton and Basala’s (1982) report that the “McGurk effect” (an influence of a visibly mouthed utterance on a dubbed acoustic one) does not occur when utterances are real words rather than nonsense syllables. In contrast, with real-word stimuli, Easton and Basala report a strong reverse effect whereby a dubbed soundtrack strongly affects identification of lipread words. In Experiment 1, we showed that a strong McGurk effect does obtain when dubbed real words are discrepant with observed words in consonantal place of articulation. A second experiment obtained only a weak reverse effect of dubbed words on judgments of lipread words. A final experiment was designed to provide a sensitive test of effects of lipread words on judgments of heard words and of heard words on judgments of lipread words. The findings reinforced those of the first two experiments that both effects occur, but, with place-of-articulation information discrepant across the modalities, the McGurk effect is strong and the reverse effect weak.     

Amplitude measures of operant response: Implementation with Apple Pascal

Because operant conditioning studies involving force of response as a dependent variable require high-speed A/D conversion, conventional operant software, which treats the input datum as a dimensionless event, is generally unsuited for this kind of work. The author describes a complete Apple-based hardware-software ensemble that measures and records on diskette the peak force, duration, time integral of force, and interresponse time for individual operant responses. Data acquisition and control programs were written in Apple Pascal linked to selected assembly language modules. The real-time base was derived from an inexpensive crystal clock interfaced     

A way out of the wasteland

This essay describes the author's experiences with Judaism, with the art of Jane Austen, and with the thought of a radical Catholic theologian, Leslie Dewart. The author's synthesis of these disparate elements indicates that it is possible to achieve a religious view that satisfies one's spiritual and emotional needs without conflicting with the widespread modern conception of the integrity and openness of man's evolution.     

Effects of UCS intensity and postpeak acquisition trials on classical conditioning of the SCR

The present study examined the effects of UCS intensity and number of postpeak acquisition trials on classical conditioning and extinction of the SCR. A 2 × 3 design was employed in which subjects received either a 1, 2, or 4 mA shock UCS and either two or 16 acquisition trials beyond the peak CR. While conditioning was demonstrated during acquisition, there was no relationship between strength of conditioning and intensity of UCS. The phenomenon of stronger resistance to extinction following fewer acquisition trials (e.g., two past the peak CR) than with many (e.g., 16 past the peak CR) was demonstrated only for the groups that were conditioned with the 4 mA UCS. Resistance to extinction varied positively with UCS intensity, but only for the subjects who received two postpeak acquisition trials. Sixteen trials beyond the peak CR resulted in the UCS intensity having little or no effect on resistance to extinction.     

Effect of multiple images on associative learning

The present research investigated the effects of multiple images on associative learning. In Experiment 1, subjects formed either a noninteractive image of two words, a single interactive image, a multiple interactive image consisting of multiple copies of the same image, or a multiple interactive image consisting of different images. In Experiment 2, the different multiple images were formed across trials instead of simultaneously during the same trial. Both experiments showed that, although interactive images are superior to noninteractive images, there is no reliable facilitation from multiple images as compared with single images. The results were discussed in terms of the variable-encoding hypothesis and previous findings that multiple retrieval paths facilitate verbal learning.     

Differential effects of noise and incentives on learning.

Three experiments are reported. In the first, monetary incentives improved the learning of nonsense words in response to colours only when the test order was the same as presentation order. In the second, incentives increased the recall of spatial location which served as an additional retrieval cue for nonsense words. In the third, noise was used to manipulate arousal. Noise during learning produced a significant decline in recall of locations for nonsense words. The results suggest that incentives increase attentional capacity, while noise does not. Previous results showing that noise increases the use of order cues are discussed and it is suggested that noise induces a type of learning which depends on order cues. Existing hypotheses about the nature of this process are noted but it is argued that further work is needed to select between them.     

Experience-Expectant Plasticity in the Mushroom Bodies of the Honeybee

Worker honeybees (Apis mellifera) were reared in social isolation in complete darkness to assess the effects of experience on growth of the neuropil of the mushroom bodies (MBs) during adult life. Comparison of the volume of the MBs of 1-day-old and 7-day-old bees showed that a significant increase in volume in the MB neuropil occurred during the first week of life in bees reared under these highly deprived conditions. All regions of the MB neuropil experienced a significant increase in volume with the exception of the basal ring. Measurement of titers of juvenile hormone (JH) in a subset of bees indicated that, as in previous studies, these rearing conditions induced in some bees the endocrine state of high JH associated with foraging, but there was no correlation between JH titer and volume of MB neuropil. Treatment of another subset of dark-reared bees with the JH analog, methoprene, also had no effect of the growth of the MB neuropil. These results demonstrate that there is a phase of MB neuropil growth early in the adult life of bees that occurs independent of light or any form of social interaction. Together with previous findings showing that an increase in MB neuropil volume begins around the time that orientation flights occur and then continues throughout the phase of life devoted to foraging, these results suggest that growth of the MB neuropil in adult bees may have both experience-expectant and experience-dependent components.