Memory encoding of stimulus features in human perceptual learning

Abstract

Two experiments analysed memory encoding in human perceptual learning. Both experiments started with preexposure without feedback to four checkerboards composed by a unique feature each and sharing a common feature (AX, BX, CX, and DX). Elements of one pair were presented intermixed and elements of the other pair were presented in separate blocks. Immediately after preexposure participants completed a memory recognition task in which the characteristics of the distractors were manipulated. Experiment 1 showed that only intermixed presentation results in good encoding of the unique features of the stimuli. Experiment 2 demonstrated that intermixed preexposure results in different encoding of unique versus common features of the stimuli: Participants are able to remember A and B better than they remember X, whereas for the blocked condition memory for C, D, and X does not differ. Overall, the results presented here support the proposal that intermixing stimuli results in differential memory traces for unique versus common features and that this contributes to the intermixed/blocked effect.

Keywords:

• Discrimination
• Memory encoding
• Perceptual learning

Acknowledgements

PFC is now at the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN. The work reported here was included in a Masters’ dissertation submitted by the first author to the University of Minho, Portugal. Research supported in part by a Multi-Year Funding Program from the Portuguese Foundation for Science and Technology (FCT). Manuscript preparation was supported in part by a Fulbright Research Fellowship to PFC. The authors would like to thank Rob Goldstone, Sarah Manlove, and three anonymous reviewers for their helpful comments to initial versions of this paper.