Unconscious Cueing via the Superior Colliculi: Evidence from Searching for Onset and Color Targets.

Isabella Fuchs,Ulrich Ansorge

doi:10.3390/brainsci2010033

Abstract

According to the bottom-up theory of attention, unconscious abrupt onsets are highly salient and capture attention via the Superior Colliculi (SC). Crucially, abrupt onsets increase the perceived contrast. In line with the SC hypothesis, unconscious abrupt-onset cues capture attention regardless of the cue color when participants search for abrupt-onset targets (Experiment 1). Also, stronger cueing effects occur for higher than lower contrast cues (Experiment 2) and for temporally, rather than nasally, presented stimuli (Experiment 3). However, in line with the known color-insensitivity of the SC, the SC pathway is shunted and unconscious abrupt-onset cues no longer capture attention when the participants have to search for color-defined targets (Experiment 4) or color-singleton targets (Experiment 5). When using color change cues instead of abrupt-onset cues, the cueing effect also vanishes (Experiment 6). Together the results support the assumption that unconscious cues can capture attention in different ways, depending on the exact task of the participants, but that one way is attentional capture via the SC. The present findings also offer a reconciliation of conflicting results in the domain of unconscious attention.

Highlights

At any instance in time, our visual world provides a vast amount of visual input
Having established subliminal attention with contrast cues and color cues under conditions in which targets can be located by their contrasts in the present Experiments 1 to 3, we turned to our test of the Superior Colliculi (SC) hypothesis
The current results were compared to a subgroup of Experiment 1 in which participants responded to a color-defined target that was cued by a black abrupt-onset cue (N = 12)

Summary

Introduction

At any instance in time, our visual world provides a vast amount of visual input. Since human mental capacity is limited, only a fraction of the available information is selected for purposes such as perception, memory and action control, while the rest of the information is ignored. This selectivity is called selective visual attention [1]. One important issue concerns the role of selective visual attention in the division of labor between unconscious (or subliminal) visual processing on the one hand and conscious vision on the other. A related important question is how this division of labor is implemented in the human brain’s visual system. One hypothesis about the relationship between conscious and unconscious vision is that selective visuo-spatial attention (i.e., the selection of positions or areas in the visual field) is a necessary (though not sufficient [2]) prerequisite for at least some forms of conscious visual perception [3,4], but see [5]

Methods

Results

Discussion

Conclusion