scholarly journals RNA induced enhancement of a simple discrimination task

1968 ◽  
Vol 12 (7) ◽  
pp. 295-296 ◽  
Author(s):  
Robert G. Gibby ◽  
David G. Crough ◽  
Samuel J. Twios
Keyword(s):  
Discrimination Task ◽  
Simple Discrimination ◽  
Simple Discrimination Task

The Perky Effect Revisited: Blocking of Visual Signals by Imagery

1969 ◽  
Vol 28 (3) ◽  
pp. 791-797 ◽  
Author(s):  
Sydney Joelson Segal ◽  
Pearl-Ellen Gordon
Keyword(s):  
Discrimination Task ◽  
Visual Signals ◽  
Simple Discrimination ◽  
Mental Images ◽  
Simple Discrimination Task ◽  
External Stimuli

Perky's 1910 observation that mental images were indistinguishable from external stimuli is considered as two issues: (1) description of images which apparently resemble the unidentified stimulus, has been given, but not satisfactorily measured; (2) poorer detection of ambiguous signals while experiencing images, has been consistently demonstrated. While distraction may play some role, the critical finding was with sensitivity ( d′), which was highest in a simple discrimination task, intermediate when Ss were told both to describe imagery and detect the signals, and poorest when they lacked information that signals might be present during imaging and relied on retrospective judgments (Perky replication). In the intermediate task, alerting Ss to the signals by having them project the slides themselves, did not alter sensitivity or bias (Lx).

scholarly journals Narrow Versus Wide Tuning Curves: What's Best for a Population Code?

1999 ◽  
Vol 11 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Alexandre Pouget ◽  
Sophie Deneve ◽  
Jean-Christophe Ducom ◽  
Peter E. Latham
Keyword(s):  
Discrimination Task ◽  
Tuning Curve ◽  
Technical Analysis ◽  
Common Belief ◽  
Simple Discrimination ◽  
Population Code ◽  
Tuning Curves ◽  
Simple Discrimination Task ◽  
Better Than

Neurophysiologists are often faced with the problem of evaluating the quality of a code for a sensory or motor variable, either to relate it to the performance of the animal in a simple discrimination task or to compare the codes at various stages along the neuronal pathway. One common belief that has emerged from such studies is that sharpening of tuning curves improves the quality of the code, although only to a certain point; sharpening beyond that is believed to be harmful. We show that this belief relies on either problematic technical analysis or improper assumptions about the noise. We conclude that one cannot tell, in the general case, whether narrow tuning curves are better than wide ones; the answer depends critically on the covariance of the noise. The same conclusion applies to other manipulations of the tuning curve profiles such as gain increase.

Stimulus Ratio Effects on Speech Discrimination by Children and Adults

1991 ◽  
Vol 34 (3) ◽  
pp. 671-678 ◽  
Author(s):  
Joan E. Sussman
Keyword(s):  
Discrimination Task ◽  
Response Pattern ◽  
Response Patterns ◽  
Speech Discrimination ◽  
Adult Group ◽  
Discrimination Accuracy ◽  
Formant Frequency ◽  
Response Strategies ◽  
Place Of Articulation ◽  
Adults And Children

This investigation examined the response strategies and discrimination accuracy of adults and children aged 5–10 as the ratio of same to different trials was varied across three conditions of a “change/no-change” discrimination task. The conditions varied as follows: (a) a ratio of one-third same to two-thirds different trials (33% same), (b) an equal ratio of same to different trials (50% same), and (c) a ratio of two-thirds same to one-third different trials (67% same). Stimuli were synthetic consonant-vowel syllables that changed along a place of articulation dimension by formant frequency transition. Results showed that all subjects changed their response strategies depending on the ratio of same-to-different trials. The most lax response pattern was observed for the 50% same condition, and the most conservative pattern was observed for the 67% same condition. Adult response patterns were most conservative across condition. Differences in discrimination accuracy as measured by P(C) were found, with the largest difference in the 5- to 6-year-old group and the smallest change in the adult group. These findings suggest that children’s response strategies, like those of adults, can be manipulated by changing the ratio of same-to-different trials. Furthermore, interpretation of sensitivity measures must be referenced to task variables such as the ratio of same-to-different trials.

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