The target article recommends that future research on subconscious processing “should focus on tasks in which participants' attention is diverted away from the experimenter's hypothesis, rather than the highly reflective tasks that are currently often employed” (Abstract). The authors also suggest that: “subtle priming effects offer considerable promise for future exploration of insight, awareness, and decision making” (sect. 6.3) and outline four criteria for a measure of awareness: reliability, relevance, immediacy, and sensitivity. The binary exclusion task meets both of these recommendations and fulfills the four criteria for a measure of awareness, but it is not mentioned in the target article.
In each trial of the binary exclusion task one of two known stimuli appears. Participants are required to respond with the stimulus that was not shown (Debner & Jacoby Reference Debner and Jacoby1994). If the stimulus is presented for long enough, participants are aware of which one was shown and respond correctly with the other one. But at brief stimulus durations, participants are more likely than chance to respond incorrectly, with the stimulus that was shown (Persaud & McLeod Reference Persaud and McLeod2007). The briefly presented stimulus must have been processed because it affected the decision about which response to make. But if it had been available to conscious processes, the participant would have responded correctly with the other stimulus. Thus the binary exclusion task with briefly presented stimuli demonstrates unconscious processing influencing decision making.
The assessment of awareness in the binary exclusion task meets all four of the criteria outlined in the target article. Since the response used to assess awareness is the same as the behavioral response, the assessment of awareness is reliable, relevant, and immediate. Using the definition of sensitivity in the target article (“same cues are provided for measuring awareness as for eliciting behavior” in Table 1), the binary exclusion task is also sensitive because only one cue is presented.
Persaud and Cowey (Reference Persaud and Cowey2008) used a binary exclusion task to compare the processing in the blind and sighted fields of the blindsight patient, GY. A square wave grating was presented to either the upper or lower quadrant of his blind or sighted field. He had to reply with an exclusion response, saying “upper” when it was in the lower field and “lower” when it was in the upper field. He claimed to see the stimuli presented to his sighted field and followed the exclusion instructions correctly. But when the stimulus was presented to his blind field, he reported that he was guessing, and his responses were significantly more often than chance incorrect. That is, he responded that the stimulus was in the quadrant in which it had been presented, not in the opposite one. When the stimuli were made clearer (the contrast between light and dark bars of the grating increased) the discrepancy between blind and sighted fields became more marked. He continued (unsurprisingly) to respond correctly to stimuli presented to his sighted field. But the probability of making an error in the blind field (replying with the quadrant in which the stimulus had been presented) increased. This is a clear demonstration of a difference between conscious and subconscious processing. Increasing the stimulus contrast decreased the error rate for consciously processed stimuli, but increasing the contrast increased the error rate for subconsciously processed stimuli.
Just as with the normal participants tested with brief stimuli by Persaud and McLeod, the experiment with GY demonstrates a clear difference between conscious and unconscious processing. Consciously processed stimuli lead to what James (Reference James1890) described as “the pursuance of future ends,” correctly following the experimenter's instructions to respond with the stimulus that was not shown. But subconsciously processed information can lead to responses that are contrary to a person's goals (Chalmers Reference Chalmers1996; Searle Reference Searle1992), erroneously responding with the stimulus that was shown.
The target article recommends that future research on subconscious processing “should focus on tasks in which participants' attention is diverted away from the experimenter's hypothesis, rather than the highly reflective tasks that are currently often employed” (Abstract). The authors also suggest that: “subtle priming effects offer considerable promise for future exploration of insight, awareness, and decision making” (sect. 6.3) and outline four criteria for a measure of awareness: reliability, relevance, immediacy, and sensitivity. The binary exclusion task meets both of these recommendations and fulfills the four criteria for a measure of awareness, but it is not mentioned in the target article.
In each trial of the binary exclusion task one of two known stimuli appears. Participants are required to respond with the stimulus that was not shown (Debner & Jacoby Reference Debner and Jacoby1994). If the stimulus is presented for long enough, participants are aware of which one was shown and respond correctly with the other one. But at brief stimulus durations, participants are more likely than chance to respond incorrectly, with the stimulus that was shown (Persaud & McLeod Reference Persaud and McLeod2007). The briefly presented stimulus must have been processed because it affected the decision about which response to make. But if it had been available to conscious processes, the participant would have responded correctly with the other stimulus. Thus the binary exclusion task with briefly presented stimuli demonstrates unconscious processing influencing decision making.
The assessment of awareness in the binary exclusion task meets all four of the criteria outlined in the target article. Since the response used to assess awareness is the same as the behavioral response, the assessment of awareness is reliable, relevant, and immediate. Using the definition of sensitivity in the target article (“same cues are provided for measuring awareness as for eliciting behavior” in Table 1), the binary exclusion task is also sensitive because only one cue is presented.
Persaud and Cowey (Reference Persaud and Cowey2008) used a binary exclusion task to compare the processing in the blind and sighted fields of the blindsight patient, GY. A square wave grating was presented to either the upper or lower quadrant of his blind or sighted field. He had to reply with an exclusion response, saying “upper” when it was in the lower field and “lower” when it was in the upper field. He claimed to see the stimuli presented to his sighted field and followed the exclusion instructions correctly. But when the stimulus was presented to his blind field, he reported that he was guessing, and his responses were significantly more often than chance incorrect. That is, he responded that the stimulus was in the quadrant in which it had been presented, not in the opposite one. When the stimuli were made clearer (the contrast between light and dark bars of the grating increased) the discrepancy between blind and sighted fields became more marked. He continued (unsurprisingly) to respond correctly to stimuli presented to his sighted field. But the probability of making an error in the blind field (replying with the quadrant in which the stimulus had been presented) increased. This is a clear demonstration of a difference between conscious and subconscious processing. Increasing the stimulus contrast decreased the error rate for consciously processed stimuli, but increasing the contrast increased the error rate for subconsciously processed stimuli.
Just as with the normal participants tested with brief stimuli by Persaud and McLeod, the experiment with GY demonstrates a clear difference between conscious and unconscious processing. Consciously processed stimuli lead to what James (Reference James1890) described as “the pursuance of future ends,” correctly following the experimenter's instructions to respond with the stimulus that was not shown. But subconsciously processed information can lead to responses that are contrary to a person's goals (Chalmers Reference Chalmers1996; Searle Reference Searle1992), erroneously responding with the stimulus that was shown.