Opposing effects of attention and consciousness on afterimages

Abstract

The brain's ability to handle sensory information is influenced by both selective attention and consciousness. There is no consensus on the exact relationship between these two processes and whether they are distinct. So far, no experiment has simultaneously manipulated both. We carried out a full factorial 2 × 2 study of the simultaneous influences of attention and consciousness (as assayed by visibility) on perception, correcting for possible concurrent changes in attention and consciousness. We investigated the duration of afterimages for all four combinations of high versus low attention and visible versus invisible. We show that selective attention and visual consciousness have opposite effects: paying attention to the grating decreases the duration of its afterimage, whereas consciously seeing the grating increases the afterimage duration. These findings provide clear evidence for distinctive influences of selective attention and consciousness on visual perception.ince the latter part of the past century, interest in the influences of selective attention and consciousness on perception has steadily increased. This discussion has raised the question of the relationship between attention and consciousness. By attention, we refer to selective perceptual attention and not vigilance or arousal; by consciousness, we refer to the content of consciousness (sometimes also referred to as awareness), and not to states of consciousness (e.g., wakefulness, dreamless sleep, or coma). Though some claim that both processes are inextricably connected (1-4), others suggest a certain level of independence (5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Psychophysical studies show that observers can pay attention to an invisible stimulus (15,16), and that a stimulus can be clearly seen in the (near) absence of attention (4,17). Though these data could be explained by arguing that these two processes covary and therefore any increase (respectively decrease) in one is associated with a similar but smaller increase (respectively decrease) in the other, this argument fails if attention and consciousness were to have opposing perceptual effects on the same stimulus. Finding such opponency would considerably strengthen the hypothesis that these processes are distinct (5).Afterimage duration is a well-suited measure for the study of attention and consciousness. Changes in afterimage durations reflect the attentional and visibility manipulations during the afterimage induction phase. This permits the temporal separation of the attentional/visibility manipulations on the afterimage inducer and their subjective monitoring, and the measurement of the resultant effects (e.g., on afterimage appearance). This procedure effectively obviates the need for a simultaneous dual-task procedure.Many afterimage and aftereffect studies are devoted to the influences of attention or consciousness in isolation. For example, removing stimuli from conscious content via various masking techniques that manipulate visibility decreases the motion aftereffect durations ...

Higher-order awareness, misrepresentation and function

“…This is unlikely. For one thing, there is now ample evidence of a double dissociation between attention and mental states' being conscious [69][70][71][72][73]; attention occurs in connection with states that are not conscious, and is absent with many states that are conscious. And it is in any case subjectively implausible that attention is needed for states to be conscious; many peripheral visual states are conscious but seemingly unattended.…”

Can binocular rivalry reveal neural correlates of consciousness?

“…Using a design very similar to that of van Boxtel et al [23], Watanabe et al [53] also independently manipulated attention and stimulus awareness, now using fMRI to measure cortical activity in human V1. In this case, the design led to the conclusion that modulations of V1 activity that co-occur with absence of awareness are entirely due to inattention, not unawareness.…”

“…The approach, in other words, entails a two-by-two design where attention and suppression are both varied, with the intention of separately assessing the effects of each factor. The approach was first developed by van Boxtel et al [23] in a study that measured negative afterimages, a psychophysical marker of neuronal adaptation. This study demonstrated that afterimages were less persistent after viewing an adapter suppressed in binocular rivalry than after viewing a visible adapter (confirming [19,20]), yet more persistent after attending away from the adapter than after attending toward it (consistent with [54,55]).…”

Bodily self-consciousness, and the primacy of self related signals such as the 1stperson perspective and self-location

“…Indeed, I have vehemently argued for such a two-way distinction (Koch & Tsuchiya, 2007). It would be interesting to see whether their theory can explain the remarkable experimental finding that attention and consciousness can sometimes have opposing effects (van Boxtel, Tsuchiya, & Koch, 2010).…”