consciousness without attention
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Curator: Dr. Naotsugu Tsuchiya, California Institute of Technology, Pasadena, CA, USA
Curator: Dr. Christof Koch, Division of Biology, Caltech, Pasadena, CA
Contents |
Consciousness in the Absence of Attention
Perception in the near absence of attention in a dual-task paradigm
In a dual-task paradigm, the subject’s attention is drawn to a demanding central task, while at the same time a secondary stimulus is flashed somewhere in the periphery (see Attention and Consciousness/How to Manipulate Attention). Using the identical retinal layout, the subject either performs the central task, or the peripheral task, or both simultaneously (Sperling and Dosher, 1986; Braun and Sagi, 1990; Braun and Julesz, 1998).
Natural scenes, gender and identity of faces can be perceived in the near absence of attention
With focal attention busy at the center, the subject can still distinguish a natural scene containing an animal (or a vehicle) from one that does not include an animal (or a vehicle) while being unable to distinguish a red-green bisected disk from a green-red one (Li et al., 2002).
Likewise, subjects can tell male from female faces or even distinguish a famous from a non-famous face (Reddy et al., 2004; Reddy et al., 2006), but are frustrated by tasks that are computationally much simpler (e.g. discriminating a rotated letter ‘L’ from a rotated ‘ T’). This is quite remarkable. Thus, although we cannot be sure that observers do not deploy some limited amount of top-down attention in these dual-task experiments that require training and concentration (that is, high arousal), it remains true that subjects can perform certain discriminations but not others in the near-absence of top-down attention. And they are not guessing. They can be quite confident of their choices and “see”, albeit often indistinctly, what they can discriminate.
Can we study perception in the complete absence of attention?
Can perception be studied in the complete absence of attention? This seems possible if, in the above-mentioned dual-task paradigm, subjects must perform a very demanding central task without needing to monitor the periphery. Such an experiment has been conducted to investigate the effects of attention on bistable perception (Pastukhov and Braun, 2007). A fundamental question in the perception of ambiguous figures is why they switch spontaneously despite constant retinal input. One influential theory posits that top-down attention triggers perceptual transitions (James, 1890). To test this, Pastukhov and Braun (Pastukhov and Braun, 2007) examined whether unattended and unreported bistable motion stimuli continued to switch. Consistent with other studies (Paffen et al., 2006), they found that drawing attention away from the peripheral ambiguous percept slowed down the dominance periods but their statistical variability remained; even a complete withdrawal of attention failed to abolish transitions. In other words, top-down attention is not necessary for switches in the content of visual consciousness. Similar dual-task experiments can likewise be applied as a strict test for the necessity of top-down attention in learning, memory, adaptation, and other cognitive functions.
References
- Braun J, Sagi D (1990) Vision outside the focus of attention. Percept Psychophys 48:45-58.
- Braun J, Julesz B (1998) Withdrawing attention at little or no cost: detection and discrimination tasks. Percept Psychophys 60:1-23.
- James W (1890) Princples of psychology. London: Mac Millan.
- Li FF, VanRullen R, Koch C, Perona P (2002) Rapid natural scene categorization in the near absence of attention. Proc Natl Acad Sci U S A 99:9596-9601.
- Paffen CL, Alais D, Verstraten FA (2006) Attention speeds binocular rivalry. Psychol Sci 17:752-756.
- Pastukhov A, Braun J (2007) Perceptual reversals need no prompting by attention. Journal of Vision.
- Reddy L, Wilken P, Koch C (2004) Face-gender discrimination is possible in the near-absence of attention. J Vis 4:106-117.
- Reddy L, Reddy L, Koch C (2006) Face identification in the near-absence of focal attention. Vision Res 46:2336-2343.
- Sperling G, Dosher B (1986) Strategy and optimization in human information processing. In: Handbook of Perception and Human Performance (Boff KR, Kaufman L, Thomas JP, eds), pp 1-65. New York: Wiley.
See also
Attention and Consciousness/How to Manipulate Attention
