A new study has found that conscious experience can be altered retrospectively, so that experience of visual information can be changed almost half a second later by manipulating where our attention is drawn.
The research, led by cognitive scientist Claire Sergent, involved asking people to stare at a centre point of a screen with two empty circles either side.
At some point, one of the two circles would fill with randomly oriented stripes for just 50ms (one twentieth of a second) and afterwards the participants were asked to say which direction the stripes were pointing in.
Crucially however, each time this happened, one of the two circles would dim either before or after the stripes appeared.
This would happen at different times – from 400ms before the stripes appeared, up to 400ms after the stripes appeared, and the dimmed circle might appear on the matching side to the stripes or on the opposite side.
Dimming one of the circles grabs your attention. It makes you instantly focus more on whichever side of space it happens.
For example, if the left-hand circle dims, it grabs your attention, and if the stripes then appear on the left, you’re more likely to make a correct judgement about which direction they’re pointing because you’re already focused on this area. But if the stripes subsequently appear on the other side, you’re distracted and you do worse.
The key discovery from this experiment was that this also happens if the dimmed circle appears after the stripes. Up to 400ms seconds after.
In other words, you perceive the original visual details that would otherwise have escaped consciousness if your attention is drawn to the area after the picture disappears. It’s like a retrospective editing of consciousness by post-event attention.
This suggests that consciousness isn’t ‘filtered’ sensory information, but an active ‘conclusion’ drawn from information distributed across senses, space and time.