Longer is not better: nonconscious overstimulation reverses priming influences under interocular suppression

Abstract

Previous research has shown that stimuli rendered invisible through masking can be sufficiently processed to induce nonconscious influences and facilitate subsequent recognition. However, masking paradigms are methodologically restricted such that stimuli cannot be presented for longer than a few tens of milliseconds, potentially restricting the strength of nonconscious influences. By adapting a masked face repetition priming paradigm to a recent interocular suppression method, we investigated whether longer periods of invisible prime stimulation lead to larger nonconscious influences on subsequent recognition. Surprisingly, we found that while brief periods of invisible prime stimulation result in classical facilitation priming, long periods of invisible stimulation lead to negative priming influences, reflecting impairment of subsequent recognition. In contrast, when the prime was visible, longer exposure resulted in classical facilitation effects, revealing qualitative differences between conscious and nonconscious processes. Altogether, the present findings reveal the existence of a nonconscious overstimulation cost, as well as an important dissociation between conscious and nonconscious processing.

Temporal structure coding with and without awareness

“…We validated this hypothesis by running a control experiment, in which a visible adaptor presented during 7 s at 0.08 Michelson contrast (i.e., with higher perceptual strength) exerted not an attractive, but a repulsive effect (effect = À0.74, t(5) = À2.81, p = 0.038). This result is similar to previous studies documenting the relationship between visual adaptation and perceptual strength of orientation features (Faivre & Kouider, 2011b), faces (Barbot & Kouider, 2012), or translational motion (Kanai & Verstraten, 2005).…”

“…We found that long-lasting apparent motion adaptors induced repulsive effects (i.e., perceiving the probe as moving horizontally after a vertical adaptor, and vice versa), while biological motion adaptors induced attractive effects (i.e., perceiving the probe as a female after a female adaptor, and vice versa). Along this line, it has been shown that increasing the duration of invisible stimuli could reverse attractive into repulsive effects (Barbot & Kouider, 2012;Faivre & Kouider, 2011b;Kanai & Verstraten, 2005). Beyond stimulus duration, the temporal dynamics that defined apparent and biological motion likewise differed: while the temporal structures carrying the direction of apparent motion ranged from 100 ms to 1200 ms (i.e., different ISIs between disks), those carrying the gender of point-light walkers ranged from 1 s (i.e., one walk cycle in the fast kinematic condition) to 3 s (i.e., one walk cycle in the slow kinematic condition).…”

What Visual Information Is Processed in the Human Dorsal Stream?

“…Recently, it has been shown that not only dorsal, but also ventral visual areas may exhibit preserved unconscious processing under CFS (Sterzer et al, 2008). Furthermore, behavioral evidence indicates that unconscious priming extends to images that are assumed to be processed along the ventral stream (Barbot and Kouider, 2012). For those reasons, the apparent dissociation between dorsal and ventral visual brain regions brought about by CFS does not seem to hold, and it can therefore be questioned whether the study by Sakuraba et al (2012) successfully isolated dorsal stream processes.…”

Exploring the boundary conditions of unconscious numerical priming effects with continuous flash suppression

“…Follow-up studies suggested that the priming effects were in fact based on elongated shape and not on tool category [ (Sakuraba, Sakai, Yamanaka, Yokosawa, & Hirayama, 2012), also see (Hebart & Hesselmann, 2012)], a finding which seems harder to reconcile with the notion of preserved action-relevant representations in parietal cortex under CFS. Note that prime durations were considerably longer (1000-3000 ms) in the numerical priming experiments by Bahrami et al (2010) than in most previously mentioned category priming experiments ($200 ms), which might have negatively influenced the numerical priming effects under interocular suppression (Barbot & Kouider, 2012).…”