Conscious access in the near absence of attention: critical extensions on the dual-task paradigm

Abstract

Whether conscious perception requires attention remains a topic of intense debate. While certain complex stimuli such as faces and animals can be discriminated outside the focus of spatial attention, many simpler stimuli cannot. Because such evidence was obtained in involving no measure of subjective insight, it remains unclear whether accurate discrimination of unattended complex stimuli is the product of automatic, unconscious processing, as in blindsight, or is accessible to consciousness. Furthermore, these paradigms typically require extensive training over many hours, bringing into question whether this phenomenon can be achieved in naive subjects. We developed a novel dual-task paradigm incorporating confidence ratings to calculate metacognition and adaptive staircase procedures to reduce training. With minimal training, subjects were able to discriminate face-gender in the near absence of top-down attentional amplification, while also displaying above-chance metacognitive accuracy. By contrast, the discrimination of simple coloured discs was significantly impaired and metacognitive accuracy dropped to chance-level, even in a partial-report condition. In a final experiment, we used blended face/disc stimuli and confirmed that face-gender but not colour orientation can be discriminated in the dual task. Our results show direct evidence for metacognitive conscious access in the near absence of attention for complex, but not simple, stimuli.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

Raised visual contrast thresholds with intact attention and metacognition in functional motor disorder

“…Perceptual decisions and confidence ratings were registered using an eight-alternative response screen (Matthews, Schröder, et al, 2018;Matthews, Wu, et al, 2018). In the Full Attention condition (Gabor Task only), subjects viewed just one response screen.…”

“…Likewise, metacognition is a critical consideration because if introspective evaluation of sensory information is impaired, differences in participants' decision criteria (i.e., their confidence in reporting a perceptual experience (Barrett, Dienes, & Seth, 2013;Fleming & Lau, 2014)) might be mistakenly interpreted as an impairment in perception itself. To overcome these experimental challenges, we employed an extended version of a psychophysical dual-task paradigm (Matthews, Schröder, Kaunitz, van Boxtel, & Tsuchiya, 2018;Sherman, Seth, Barrett, & Kanai, 2015) to study all four domains at once in FMDs. In addition to healthy controls, we selected a comparison group with matched organic motor disorders to control for the effects of motor disability alone.…”

Recent evidence that attention is necessary, but not sufficient, for conscious perception

“…Matthews et al . presented results from a modified dual‐task paradigm that suggests conscious awareness of stimuli in the near absence of attention . In the conventional dual‐task paradigm, a demanding central task is designed to fully engage attention, while a secondary peripheral task is designed to simultaneously probe cognitive access to information outside the focus of attention.…”

“…Matthews et al presented results from a modified dual-task paradigm that suggests conscious awareness of stimuli in the near absence of attention. 64 In the conventional dual-task paradigm, a demanding central task is designed to fully engage attention, while a secondary peripheral task is designed to simultaneously probe cognitive access to information outside the focus of attention. If performance on the peripheral task is found to be identical between the dual-task condition and a single-task condition in which attention is not constrained to the central task, then attention is thought to be unnecessary for the performance of the peripheral task, and according to some arguments, unnecessary for the conscious perception of certain classes of stimuli.…”

Sustained conscious access to incidental memories in RSVP

“…These memories extend to at least seven intervening faces, are robust to the masking qualities of saccadic eye-movements, and, critically, are associated with above-chance metacognitive accuracy. Metacognitive accuracy is a marker of conscious access that highlights the functional quality of incidental memory (Matthews, Schröder, Kaunitz, van Boxtel, & Tsuchiya, 2018;Nelson, 1996). In contrast, when the same procedure was applied to inverted scenes, incidental memory for inverted, distractor faces was limited to between three and five items, within the traditional limits associated with visual short-term memory (Luck & Vogel, 1997).…”