Clinical Example of Subjective Memory

Introduction by the Blog Author
A test was conducted about the memory of visual information. A picture was shown of faint lines and a circular shape. The faint lines were made to vanish and, subsequently, the circle was dimmed. It was found that the dimming of the circle improved the chances that the lines would be noticed. This demonstrates subjective editing of what we have seen and its effect on what we remember.

Elsewhere, it has been suggested that the same editing takes place with what we hear, and that, by such editing, we are able to learn languages.

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Cueing Attention after the Stimulus Is Gone Can Retrospectively Trigger Conscious Perception

Current Biology, Volume 23, Issue 2, pages150-155, 13 December 2012

Authors -- Claire Sergent, Valentin Wyart, Mariana Babo-Rebelo, Larent Cohen, Lionel Naccache, Catherine Tallon-Baudry

 

• Highlights
• Orienting our attention after stimulus offset can make us perceive it consciously
• This retroperception effect can occur as late as 400 ms after stimulus presentation

　

Summary

Is our perceptual experience of a stimulus entirely determined during the early buildup of the sensory representation, within 100 to 150 ms following stimulation [1,2]? Or can later influences, such as sensory reactivation, still determine whether we become conscious of a stimulus [3,4]? Late visual reactivation can be experimentally induced by postcueing attention after visual stimulus offset [5]. In a contrary approach from previous work on postcued attention and visual short-term memory, which used multiple item displays [6,7], we tested the influence of postcued attention on perception, using a single visual stimulus (Gabor patch) at threshold contrast. We showed that attracting attention to the stimulus location 100 to 400 ms after presentation still drastically improved the viewers objective capacity to detect its presence and to discriminate its orientation, along with drastic increase in subjective visibility. This retroperception effect demonstrates that postcued attention can retrospectively trigger the conscious perception of a stimulus that would otherwise have escaped consciousness. It was known that poststimulus events could either suppress consciousness, as in masking, or alter conscious content, as in the flash-lag illusion. Our results show that conscious perception can also be triggered by an external event several hundred ms after stimulus offset, underlining unsuspected temporal flexibility in conscious perception.

Full text available at:

http://www.cell.com/current-biology/abstract/S0960-9822(12)01391-7