Hippocampal stimulation disrupts spatial working memory even 8 h after acquisition

The present experiment used hippocampal stimulation to determine the temporal gradient of consolidation of spatial working memory. Rats were trained to perform a spatial working memory task on a radial maze with 12 arms. Each rat went to the ends of 6 arms to obtain a food reward. After 8 h, the rat chose among all the arms to find the ones not previously chosen (and consequently still having food). During some test sessions, the hippocampus was stimulated electrically either at a current level just high enough to produce an electrophysiological seizure, or at a current level below this seizure threshold. Stimulation occurred at one of five intervals (0 to 8 h) following the completion of the first six choices. During other test sessions, the hippocampus was not stimulated. After seizure stimulation, the number of retroactive errors (returning to arms chosen prior to stimulation) increased at all delay intervals; the number of proactive errors (returning to arms chosen after stimulation) increased only with the delay of 8 h. Subthreshold stimulation had no influence on either type of error. These results indicate that normal hippocampal function is required for the maintenance of spatial information in working memory, and that the time course of consolidation of this information is significantly greater than that seen in other types of memory, or consolidation may not take place at all.     

Some effects of color on naming and recognition of objects

In this article, we investigated the role of color in the recognition and naming of everyday objects. In the first experiment we found that color pictures were named faster than black-and-white and that shape information did not facilitate color naming. Experiment 2 was carried out to determine at which stage of object processing the color facilitation occurred. We found that color had no effect on object recognition but did facilitate object naming, even when color was redundant for discrimination. This did not apply to naming abstract shapes. Experiment 3 replicated the findings of Experiment 2 using different objects and colors. The results showed that color could facilitate but not inhibit object naming and did not affect object recognition.     

The Attitudes Toward Women Scale for Adolescents (AWSA): A study of reliability and validity

This study describes the development of the Attitudes Toward Women Scale for Adolescents (AWSA), an instrument based on the short form of the Spence-Helmreich Attitudes Toward Women Scale (AWS). The AWSA has been tested in four samples of adolescents. Internal consistency estimates and test-retest stability indicated high reliability. Hypotheses formulated to test the construct validity of the scale were largely supported. AWSA permits the examination of how boys' and girls' attitudes toward women influence the life paths that adolescent girls begin to pursue.This research was supported by grants to A. Petersen from the Spencer Foundation, the National Institute of Mental health (MH 30252/38142), and the Judith Baskin Offer Fund.     

Heart-rate responses of infant rats and guinea pigs to stimulus onset and offset: tests of the generality of a bidirectional effect

To test the generality, across modality and across species, of a bidirectional effect of photic stimulation in infant rats found in previous experiments, two experiments examined the effects on heart rate (HR) of onset and offset of auditory stimulation in rats and of photic stimulation in guinea pigs. Experiment 1 demonstrated a unidirectional, decelerative response in rats 17 and 21 days of age to the onset and offset of a 1-kHz tone, at both low (80 dB) and high (100 dB) intensity levels and at 14 days to the onset of the high-intensity tone. Experiment 2 demonstrated that infant guinea pigs, which unlike infant rats are precocial and not nocturnal, responded to the offset but not to the onset of light, and that this response was decelerative. These results indicated a lack of generality of the bidirectional HR effect, and were discussed in terms of the orienting/defensive reflex distinction.     

Color discrimination on Mangaia

Bornstein’s hypothesis that there is a loss of color discrimination in tropical areas was not supported in earlier research in the Cook Islands. Using a more sensitive color vision test (the Farnsworth-Munsell 100-Hue Test), a loss of color discrimination in the red-purple and blue-green regions of the spectrum was found. The lack of sex differences in this color discrimination loss supports a physiological rather than a genetic explanation of the observed decrement.     

A functional analysis of social reinforcement in vicarious verbal conditioning

This article reports the results of 629 subjects in three experiments designed to replicate and extend the phenomenon of vicarious verbal conditioning. Experiment I replicated the finding that subjects who responded most to vicarious verbal conditioning were aware of the contingency involved. Experiment II attempted to examine the effects of prior history with the verbal reinforcer on vicarious verbal conditioning by providing seven groups of subjects with varying classic conditioning histories prior to vicarious verbal conditioning. The null results associated with this experiment were hypothesized to be due to the fact that the vicarious verbal conditioning took place in a language laboratory where the subjects could hear but not see the model. Experiment III replicated Experiment II in a live group context as was done in Experiment I. The results showed a) that vicarious verbal conditioning was again found to take place, b) that associating the verbal reinforcer with a tone or tone plus money via forward classic conditioning potentiated the effects of the verbal reinforcer, c) that backward classic conditioning did not potentiate the reinforcer, d) nor did either of two sensitization procedures potentiate the effects of the verbal reinforcer. Both aware and unaware subjects evidenced vicarious verbal conditioning.     

Achromatic color categories

Sternheim and Boynton’s (1966) continuous judgmental color-naming technique was used to assess the elemental nature of achromatic colors. Results from three subjects indicate that the names “black” and “white” are necessary and sufficient to describe achromatic test lights associated with the name “gray.” On the basis of the criteria that establishes a color as elemental, black and white were confirmed as elemental, whereas gray was not. These findings support the assumption of various opponent processing models that there are only two elemental achromatic sensations. In addition, the results support Hering’s (1920) view that black and white differ from the paired-chromatic opponent colors in that they are not mutually exclusive.