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Long-term memory for elementary visual percepts: memory psychophysics of context and acquisition effects
William M Petrusic1, Derek H Harrison, Joseph V Baranski
1Department of Psychology, Carleton University, Ottawa, Ontario, Canada. bill_petrusic@carleton.ca
Perception & Psychophysics
|July 31, 2004
Summary
Memory precision is lower for remembered standards than perceptual ones, with central items showing poorer discriminability. This suggests a noisy memory representation, not a direct functional equivalence between perception and memory.
Area of Science:
- Cognitive Psychology
- Psychophysics
- Human Memory Research
Background:
- Paired-associate learning is used to link abstract labels (consonant-vowel-consonant) with concrete stimuli (line lengths).
- The method of constant stimuli allows for the measurement of discriminative performance using psychometric functions.
Purpose of the Study:
- To investigate the precision of remembered magnitudes used as memorial standards.
- To compare discriminative performance between remembered and perceptual standards.
- To explore factors influencing memory precision, such as set size and acquisition trials.
Main Methods:
- Participants learned label-line length associations via paired-associate learning.
- Learned labels served as memorial standards in the method of constant stimuli to obtain Weber fractions (WFs).
- WFs were compared between remembered and perceptual standards, analyzing effects of serial position, set size, and acquisition trials.
Main Results:
- Weber fractions (WFs) were higher for remembered standards, indicating poorer discriminability compared to perceptual standards.
- Remembered standards showed serial position effects and varied with set size, unlike perceptual standards.
- Increased acquisition trials reduced WFs and diminished serial position effects for remembered standards.
- Ordinal spacing, not physical spacing, affected WFs for remembered standards.
- Time-order error effects were observed in perception but not in memory comparisons.
Conclusions:
- Results support a noisy analogue representation model for remembered magnitudes, with central items experiencing lateral inhibition.
- The findings challenge a strong functional equivalence view between perception and memory due to the absence of presentation order effects in memory comparisons.