Conceptual and visual features contribute to visual memory for natural images.

Gesche M Huebner,Karl R Gegenfurtner,Mark W Greenlee

doi:10.1371/journal.pone.0037575

Abstract

We examined the role of conceptual and visual similarity in a memory task for natural images. The important novelty of our approach was that visual similarity was determined using an algorithm [1] instead of being judged subjectively. This similarity index takes colours and spatial frequencies into account. For each target, four distractors were selected that were (1) conceptually and visually similar, (2) only conceptually similar, (3) only visually similar, or (4) neither conceptually nor visually similar to the target image. Participants viewed 219 images with the instruction to memorize them. Memory for a subset of these images was tested subsequently. In Experiment 1, participants performed a two-alternative forced choice recognition task and in Experiment 2, a yes/no-recognition task. In Experiment 3, testing occurred after a delay of one week. We analyzed the distribution of errors depending on distractor type. Performance was lowest when the distractor image was conceptually and visually similar to the target image, indicating that both factors matter in such a memory task. After delayed testing, these differences disappeared. Overall performance was high, indicating a large-capacity, detailed visual long-term memory.

Highlights

It is a well-established finding that long-term memory for images is extensive and that thousands of items can be stored [2,3,4,5]
We examined the role of the conceptual and visual similarity between a target and distractor image on performance in a memory task
We showed that participants extracted and remembered both conceptual and visual information when looking at natural scenes in preparation for a memory task

Summary

Introduction

It is a well-established finding that long-term memory for images is extensive and that thousands of items can be stored [2,3,4,5]. Even when 10,000 images were shown [4], participants were able to decide with an accuracy of 83% which of two images they had seen. This remarkable ability to successfully discriminate between targets and distractors did not necessarily mean that a detailed representation of each image was created and stored. Distractor and target images were rather dissimilar in those studies, possibly allowing participants to rely upon merely storing the basic meaning of an image, in terms of a short verbal description. To evaluate what such a seemingly remarkable memory performance means, a measure of the level of stored detail would be needed

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Discussion

Conclusion