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H. Steven Scholte, Manon Mulckhuyse, Judith Tankink, Victor A. Lamme; Attention can operate independently of awareness. Journal of Vision 2006;6(6):300. doi: 10.1167/6.6.300.
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© ARVO (1962-2015); The Authors (2016-present)
Numerous experiments show that people are unable to report on unattended information, especially when subjects are not informed about the presence of these stimuli. Does this mean that attention determines what we are aware off?
We investigated this by presenting subjects with an RSVP of letters that were either hard or easy to discriminate (manipulated by varying the contrast between target and non-target letters). With the onset of the target letter we presented a texture composed of homogeneously oriented line elements or a texture in which a checkerboard could be perceived. Subjects participated in an inattention condition in which they were only informed about the RSVP and we either measured EEG or BOLD-MRI. Subjects that, after the experiment, failed to identify the checkerboard texture participated in two other conditions: a condition in which they again responded to the RSVP and a condition in which they also had to detect the presence of the checkerboard textures. ERPs indicate that a figure induced occipital negativity (∼160–200 ms) has lower amplitude when the letters of the RSVP are difficult to discriminate compared to easy to discriminate. This amplitude reduction is not influenced by condition. Later activity is influenced by condition. Results from BOLD-MRI are consistent with this pattern.
This indicates that attention determines the amount of processing of stimuli, even when subjects are not aware of stimuli. Results also indicate that the amount of processing in an inattention paradigm is determined by the difficulty of the task that subjects are informed about.
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