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Steven J. Haase - One of the best experts on this subject based on the ideXlab platform.
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Binary vs. continuous experimental designs for the study of Unconscious perceptual processing.
Consciousness and cognition, 2020Co-Authors: Gary D. Fisk, Steven J. HaaseAbstract:Abstract Binary vs. continuous conceptualizations of consciousness may have an unstated influence on experimental designs in Unconscious Perception research. The binary approach aims to compare a conscious condition (e.g., supraliminal, no or weak stimulus masking) to an Unconscious condition (e.g., subliminal, heavy stimulus masking). In contrast, continuous designs tend to vary stimulus energy along a near-threshold continuum to determine changes in Perception as a function of stimulus energy (or duration). The present study compared two experimental designs, binary vs. continuous, for the influence of target-masked prime stimuli on a Stroop task. The display parameters were inspired by emotional Stroop studies reporting Unconscious Perception. Neither experiment produced strong evidence of Unconscious Perception, but the experiment with a continuous design was more informative. We thus recommend sampling a range of near-threshold display parameters to yield straight-forward, unambiguous interpretations.
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Extending a focused attention paradigm to critically test for Unconscious congruency effects
Visual Cognition, 2020Co-Authors: Steven J. Haase, Gary D. FiskAbstract:In a novel integration of research designs, we tested for Unconscious Perception effects at an unattended stimulus location using a focused attention paradigm (Lachter, J., Forster, K. I., & Ruthru...
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Commentary on: “Evidence of weak conscious experiences in the exclusion task”
Frontiers in psychology, 2015Co-Authors: Gary D. Fisk, Steven J. HaaseAbstract:Most studies of Unconscious Perception aim to demonstrate that the participants are unaware of the prime stimuli (e.g., a measurement of zero sensitivity on prime detection, discrimination, or identification) yet show evidence of Perception on another variable (e.g., semantic priming). Dissociation studies of this kind are popular, but the approach has an inherently weak logic. The problem is the need to establish that the awareness measure is exhaustively sensitive to conscious Perception (Reingold and Merikle, 1988). The exhaustiveness issue is critical. If exhaustiveness cannot be demonstrated, any findings suggesting Unconscious Perception can be plausibly attributed to a Type II statistical error (a failure to measure a real effect on the awareness measure) and are open to alternative interpretations. Sandberg et al. (2014) investigated this exhaustiveness issue by comparing two different methods of measuring awareness in an Unconscious Perception paradigm. The Perceptual Awareness Scale (PAS) is a direct report of stimulus awareness that is expressed on a four point scale (1: no experience, 2: weak glimpse, 3: an almost clear experience, and 4: A clear experience; Ramsoy and Overgaard, 2004). The PAS was compared to an exclusion task that required the participants to intentionally respond in ways that did not match the presented prime stimuli (Debner and Jacoby, 1994; Merikle et al., 1995). Exclusion task results are interpreted as evidence for Unconscious Perception if the participants match the prime and response at elevated rates (i.e., exclusion failure; an inability to follow instructions presumably due to Unconscious Perception). Sandberg et al. found significantly elevated prime—response exclusion matches on trials that were rated 1 (“no experience”) or 2 (“weak glimpse”) on the PAS. Exclusion failure at the 2 rating suggested that exclusion failure should not always be interpreted as evidence of Unconscious Perception because exclusion failure can occur when there is a weak degree of stimulus awareness. The investigators concluded that the PAS is more sensitive (exhaustive) to the presence of conscious Perception than the exclusion task. If this is true, then the conclusions of previous studies (e.g., Debner and Jacoby, 1994; Merikle et al., 1995; Smith and Bulman-Fleming, 2004; Matsumoto et al., 2005; Lamy et al., 2008) that interpreted exclusion failure as evidence of Unconscious Perception may be in doubt because the findings may be partly attributable to conscious Perception. Another important implication is that direct measures of awareness (PAS) may be more sensitive than indirect measures (exclusion), which is contrary to the views of some investigators. We would like to support Sandberg et al.'s conclusions by adding that we have obtained similar findings in an experiment that compared an exclusion task to word discrimination performance (Fisk and Haase, 2007; Experiment 3). The participants observed masked word or nonword stimuli that were presented for 75 ms. Half of the trials contained words; the other half, nonwords. Prime sensitivity was determined after each presentation by asking the participants to indicate the presence of a word on a word-nonword discrimination scale that ranged from 1 (“No word was presented”) to 6 (“Yes, a word was presented”). The second response on each trial was an exclusion task. The results from the word trials showed that exclusion failure did not occur at the low discrimination ratings. In contrast, the exclusion failure rate was above baseline and consistent for trials with ratings three through six. This latter result is similar to Sandberg et al. in that exclusion failure was accompanied by evidence that the prime stimuli were consciously perceived. The word/nonword discrimination sensitivity this experiment was da = 0.74, which is well above the zero sensitivity expected for null awareness. When exclusion failure and word-nonword discrimination sensitivity were compared in separate blocks of trials exclusion failure also occurred at display settings with significant prime discrimination sensitivity (58 ms; da = 0.35; 75 ms; da = 0.82; Experiment 2). Overall, these results are consistent with Sandberg et al. in showing that a direct measure of stimulus Perception is more sensitive to the influence of conscious Perception than the exclusion task. Although these studies reached similar conclusions, there were some noteworthy differences in the results. In particular, Sandberg et al. found exclusion failure effects at the lowest level of the PAS (1—“no experience”), but our study (2007, Experiment 3) found no evidence of exclusion failure at the lower levels of the discrimination rating scale (“1” and “2” ratings; “See Figure 3B of Fisk and Haase, 2007”). Methodology differences may partly explain the discrepancies. The key difference is in the task requirements: the PAS emphasizes reporting stimulus awareness or experience, whereas our word discrimination task emphasized confidence that a word was displayed (i.e., distinguishing words from nonwords). There were other methodology differences too, such as the stimulus displays (0–200 ms vs. 75 ms), stimuli presented on the trials (all words vs. 50% words and 50% nonwords) and setting baseline responses (0 ms vs. nonword trials). Aside from the above differences it is not entirely clear why Sandberg et al. found exclusion success (nonmatching, proper performance) at higher ratings of the PAS whereas our results were essentially the opposite (i.e., exclusion failure—matching—at the higher ratings of word discrimination confidence). We, too, have found exclusion success at high ratings in a 2AFC exclusion task (Haase and Fisk, 2001; Fisk and Haase, 2006). Although there are clear differences between these studies, we would like to emphasize again that the general approach and the main conclusions of both studies—that exclusion failure is sometimes accompanied by significant conscious Perception of the target stimuli—are essentially the same. Sandberg et al.'s research provides converging evidence that is an important contribution to our understanding of the influence of conscious awareness in the exclusion task paradigm. Early advocates of using the exclusion task and the Process Dissociation Procedure for studying Unconscious Perception argued that this approach was advantageous because it circumvented the need to establish null awareness and exhaustive sensitivity (Jacoby and Kelley, 1992; Merikle and Joordens, 1997). In contrast, accumulating evidence from Sandberg et al. and others (Snodgrass, 2002; Fisk and Haase, 2006, 2007, 2013; Bengson and Hutchison, 2007) increasingly suggests that exclusion tasks lack validity for studying Unconscious Perception. Exclusion failure effects may represent weak conscious Perception rather than Unconscious Perception. Therefore, we feel that investigations of Unconscious Perception would be better served by using direct ratings of stimulus awareness such as the PAS or other traditional measures, such as detection, identification, and discrimination.
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Highly correlated stimuli do not necessarily facilitate the measurement of Unconscious Perception: Exclusion failure is hard to find in forced-choice tasks
Consciousness and cognition, 2013Co-Authors: Gary D. Fisk, Steven J. HaaseAbstract:Abstract Persaud and McLeod (2008) report that Unconscious Perception is easier to measure with forced-choice exclusion tasks when the stimuli are highly similar, such as choosing between the letters ‘h’ and ‘b’. The high degree of stimulus similarity may decrease conscious awareness of the target stimuli while leaving Unconscious cognition intact. The present experiments used forced-choice exclusion tasks (i.e., choosing the opposite of a masked target stimulus) with the aim of replicating these findings. No evidence of relevant Perception – either conscious or Unconscious – was obtained with short duration targets. The forced-choice exclusion task was correctly performed at longer target durations (25 ms and higher), which suggests conscious Perception of the target stimuli. We conclude that increasing stimulus similarity does not reliably produce exclusion failure effects and does not appear to facilitate the measurement of Unconscious cognition.
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the relationship between the objective identification threshold and priming effects does not provide a definitive boundary between conscious and Unconscious perceptual processes
Consciousness and Cognition, 2011Co-Authors: Gary D. Fisk, Steven J. HaaseAbstract:Abstract The Objective Threshold/Strategic Model (OT/S) proposes that strong, qualitative inferences of Unconscious Perception can be made if the relationship between perceptual sensitivity (typically priming effects) and stimulus visibility is nonlinear and nonmonotonic. The model proposes a nadir in priming effects at the objective identification threshold (identification d′ = 0). These predictions were tested with masked semantic priming and repetition priming of a lexical decision task. The visibility of the prime stimuli was systematically varied above and below the objective identification threshold. The obtained relationship between prime visibility and priming facilitation was nonlinear, but the results failed to confirm a nadir in priming effects at the objective identification threshold. We conclude that the objective identification threshold does not necessarily indicate the point where presumably Unconscious priming effects might be inhibited by conscious cognitive processes.
Gary D. Fisk - One of the best experts on this subject based on the ideXlab platform.
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Binary vs. continuous experimental designs for the study of Unconscious perceptual processing.
Consciousness and cognition, 2020Co-Authors: Gary D. Fisk, Steven J. HaaseAbstract:Abstract Binary vs. continuous conceptualizations of consciousness may have an unstated influence on experimental designs in Unconscious Perception research. The binary approach aims to compare a conscious condition (e.g., supraliminal, no or weak stimulus masking) to an Unconscious condition (e.g., subliminal, heavy stimulus masking). In contrast, continuous designs tend to vary stimulus energy along a near-threshold continuum to determine changes in Perception as a function of stimulus energy (or duration). The present study compared two experimental designs, binary vs. continuous, for the influence of target-masked prime stimuli on a Stroop task. The display parameters were inspired by emotional Stroop studies reporting Unconscious Perception. Neither experiment produced strong evidence of Unconscious Perception, but the experiment with a continuous design was more informative. We thus recommend sampling a range of near-threshold display parameters to yield straight-forward, unambiguous interpretations.
-
Extending a focused attention paradigm to critically test for Unconscious congruency effects
Visual Cognition, 2020Co-Authors: Steven J. Haase, Gary D. FiskAbstract:In a novel integration of research designs, we tested for Unconscious Perception effects at an unattended stimulus location using a focused attention paradigm (Lachter, J., Forster, K. I., & Ruthru...
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Commentary on: “Evidence of weak conscious experiences in the exclusion task”
Frontiers in psychology, 2015Co-Authors: Gary D. Fisk, Steven J. HaaseAbstract:Most studies of Unconscious Perception aim to demonstrate that the participants are unaware of the prime stimuli (e.g., a measurement of zero sensitivity on prime detection, discrimination, or identification) yet show evidence of Perception on another variable (e.g., semantic priming). Dissociation studies of this kind are popular, but the approach has an inherently weak logic. The problem is the need to establish that the awareness measure is exhaustively sensitive to conscious Perception (Reingold and Merikle, 1988). The exhaustiveness issue is critical. If exhaustiveness cannot be demonstrated, any findings suggesting Unconscious Perception can be plausibly attributed to a Type II statistical error (a failure to measure a real effect on the awareness measure) and are open to alternative interpretations. Sandberg et al. (2014) investigated this exhaustiveness issue by comparing two different methods of measuring awareness in an Unconscious Perception paradigm. The Perceptual Awareness Scale (PAS) is a direct report of stimulus awareness that is expressed on a four point scale (1: no experience, 2: weak glimpse, 3: an almost clear experience, and 4: A clear experience; Ramsoy and Overgaard, 2004). The PAS was compared to an exclusion task that required the participants to intentionally respond in ways that did not match the presented prime stimuli (Debner and Jacoby, 1994; Merikle et al., 1995). Exclusion task results are interpreted as evidence for Unconscious Perception if the participants match the prime and response at elevated rates (i.e., exclusion failure; an inability to follow instructions presumably due to Unconscious Perception). Sandberg et al. found significantly elevated prime—response exclusion matches on trials that were rated 1 (“no experience”) or 2 (“weak glimpse”) on the PAS. Exclusion failure at the 2 rating suggested that exclusion failure should not always be interpreted as evidence of Unconscious Perception because exclusion failure can occur when there is a weak degree of stimulus awareness. The investigators concluded that the PAS is more sensitive (exhaustive) to the presence of conscious Perception than the exclusion task. If this is true, then the conclusions of previous studies (e.g., Debner and Jacoby, 1994; Merikle et al., 1995; Smith and Bulman-Fleming, 2004; Matsumoto et al., 2005; Lamy et al., 2008) that interpreted exclusion failure as evidence of Unconscious Perception may be in doubt because the findings may be partly attributable to conscious Perception. Another important implication is that direct measures of awareness (PAS) may be more sensitive than indirect measures (exclusion), which is contrary to the views of some investigators. We would like to support Sandberg et al.'s conclusions by adding that we have obtained similar findings in an experiment that compared an exclusion task to word discrimination performance (Fisk and Haase, 2007; Experiment 3). The participants observed masked word or nonword stimuli that were presented for 75 ms. Half of the trials contained words; the other half, nonwords. Prime sensitivity was determined after each presentation by asking the participants to indicate the presence of a word on a word-nonword discrimination scale that ranged from 1 (“No word was presented”) to 6 (“Yes, a word was presented”). The second response on each trial was an exclusion task. The results from the word trials showed that exclusion failure did not occur at the low discrimination ratings. In contrast, the exclusion failure rate was above baseline and consistent for trials with ratings three through six. This latter result is similar to Sandberg et al. in that exclusion failure was accompanied by evidence that the prime stimuli were consciously perceived. The word/nonword discrimination sensitivity this experiment was da = 0.74, which is well above the zero sensitivity expected for null awareness. When exclusion failure and word-nonword discrimination sensitivity were compared in separate blocks of trials exclusion failure also occurred at display settings with significant prime discrimination sensitivity (58 ms; da = 0.35; 75 ms; da = 0.82; Experiment 2). Overall, these results are consistent with Sandberg et al. in showing that a direct measure of stimulus Perception is more sensitive to the influence of conscious Perception than the exclusion task. Although these studies reached similar conclusions, there were some noteworthy differences in the results. In particular, Sandberg et al. found exclusion failure effects at the lowest level of the PAS (1—“no experience”), but our study (2007, Experiment 3) found no evidence of exclusion failure at the lower levels of the discrimination rating scale (“1” and “2” ratings; “See Figure 3B of Fisk and Haase, 2007”). Methodology differences may partly explain the discrepancies. The key difference is in the task requirements: the PAS emphasizes reporting stimulus awareness or experience, whereas our word discrimination task emphasized confidence that a word was displayed (i.e., distinguishing words from nonwords). There were other methodology differences too, such as the stimulus displays (0–200 ms vs. 75 ms), stimuli presented on the trials (all words vs. 50% words and 50% nonwords) and setting baseline responses (0 ms vs. nonword trials). Aside from the above differences it is not entirely clear why Sandberg et al. found exclusion success (nonmatching, proper performance) at higher ratings of the PAS whereas our results were essentially the opposite (i.e., exclusion failure—matching—at the higher ratings of word discrimination confidence). We, too, have found exclusion success at high ratings in a 2AFC exclusion task (Haase and Fisk, 2001; Fisk and Haase, 2006). Although there are clear differences between these studies, we would like to emphasize again that the general approach and the main conclusions of both studies—that exclusion failure is sometimes accompanied by significant conscious Perception of the target stimuli—are essentially the same. Sandberg et al.'s research provides converging evidence that is an important contribution to our understanding of the influence of conscious awareness in the exclusion task paradigm. Early advocates of using the exclusion task and the Process Dissociation Procedure for studying Unconscious Perception argued that this approach was advantageous because it circumvented the need to establish null awareness and exhaustive sensitivity (Jacoby and Kelley, 1992; Merikle and Joordens, 1997). In contrast, accumulating evidence from Sandberg et al. and others (Snodgrass, 2002; Fisk and Haase, 2006, 2007, 2013; Bengson and Hutchison, 2007) increasingly suggests that exclusion tasks lack validity for studying Unconscious Perception. Exclusion failure effects may represent weak conscious Perception rather than Unconscious Perception. Therefore, we feel that investigations of Unconscious Perception would be better served by using direct ratings of stimulus awareness such as the PAS or other traditional measures, such as detection, identification, and discrimination.
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Highly correlated stimuli do not necessarily facilitate the measurement of Unconscious Perception: Exclusion failure is hard to find in forced-choice tasks
Consciousness and cognition, 2013Co-Authors: Gary D. Fisk, Steven J. HaaseAbstract:Abstract Persaud and McLeod (2008) report that Unconscious Perception is easier to measure with forced-choice exclusion tasks when the stimuli are highly similar, such as choosing between the letters ‘h’ and ‘b’. The high degree of stimulus similarity may decrease conscious awareness of the target stimuli while leaving Unconscious cognition intact. The present experiments used forced-choice exclusion tasks (i.e., choosing the opposite of a masked target stimulus) with the aim of replicating these findings. No evidence of relevant Perception – either conscious or Unconscious – was obtained with short duration targets. The forced-choice exclusion task was correctly performed at longer target durations (25 ms and higher), which suggests conscious Perception of the target stimuli. We conclude that increasing stimulus similarity does not reliably produce exclusion failure effects and does not appear to facilitate the measurement of Unconscious cognition.
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the relationship between the objective identification threshold and priming effects does not provide a definitive boundary between conscious and Unconscious perceptual processes
Consciousness and Cognition, 2011Co-Authors: Gary D. Fisk, Steven J. HaaseAbstract:Abstract The Objective Threshold/Strategic Model (OT/S) proposes that strong, qualitative inferences of Unconscious Perception can be made if the relationship between perceptual sensitivity (typically priming effects) and stimulus visibility is nonlinear and nonmonotonic. The model proposes a nadir in priming effects at the objective identification threshold (identification d′ = 0). These predictions were tested with masked semantic priming and repetition priming of a lexical decision task. The visibility of the prime stimuli was systematically varied above and below the objective identification threshold. The obtained relationship between prime visibility and priming facilitation was nonlinear, but the results failed to confirm a nadir in priming effects at the objective identification threshold. We conclude that the objective identification threshold does not necessarily indicate the point where presumably Unconscious priming effects might be inhibited by conscious cognitive processes.
Jason F. Anderson - One of the best experts on this subject based on the ideXlab platform.
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A dissociation between detection and identification of phobic stimuli: Unconscious Perception?
Cognition & Emotion, 2013Co-Authors: Paul Siegel, Edward Han, Don Cohen, Jason F. AndersonAbstract:A psychophysical paradigm for investigating Unconscious Perception was used to test the hypothesis of dissociation between detection and identification of phobic stimuli. Spider-phobic and non-phobic participants were presented with masked images of spiders and flowers and an equal number of control stimuli in a random sequence. After each masked stimulus was flashed, participants first reported whether or not an object was presented. Then they identified each stimulus as either a spider or a flower, regardless of their prior detection response. Phobic participants identified both detected and undetected spiders better than chance, as assessed by two measures of response bias. They did not exhibit dissociation between detection and identification for flowers. Non-phobic participants did not exhibit detection–identification dissociation for either spiders or flowers. These results are consistent with the interpretation that phobic individuals Unconsciously perceive their feared stimulus, and constitute the...
Dominique Lamy - One of the best experts on this subject based on the ideXlab platform.
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Neural Correlates of Subjective Awareness and Unconscious Processing: An ERP Study
Journal of Cognitive Neuroscience, 2009Co-Authors: Dominique Lamy, Moti Salti, Yair Bar-haimAbstract:The aim of the present study was to dissociate the ERP (Event Related Potentials) correlates of subjective awareness from those of Unconscious Perception. In a backward masking paradigm, participants first produced a forced-choice response to the location of a liminal target presented for an individually calibrated duration, and then reported on their subjective awareness of the target's presence. We recorded (Event-Related Potentials) ERPs and compared the ERP waves when observers reported being aware vs. unaware of the target but localized it correctly, thereby isolating the neural correlates of subjective awareness while controlling for differences in objective performance. In addition, we compared the ERPs when participants were subjectively unaware of the target's presence and localized it correctly versus incorrectly, thereby isolating the neural correlates of Unconscious Perception. All conditions involved stimuli that were physically identical and were presented for the same duration. Both behavioral measures were associated with modulation of the amplitude of the P3 component of the ERP. Importantly, this modulation was widely spread across all scalp locations for subjective awareness, but was restricted to the parietal electrodes for Unconscious Perception. These results indicate that liminal stimuli that do not affect performance undergo considerable processing and that subjective awareness is associated with a late wave of activation with widely distributed topography.
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Unconscious auditory information can prime visual word processing a process dissociation procedure study
Consciousness and Cognition, 2008Co-Authors: Dominique Lamy, Liad Mudrik, Leon Y. DeouellAbstract:Whether information perceived without awareness can affect overt performance, and whether such effects can cross sensory modalities, remains a matter of debate. Whereas influence of Unconscious visual information on auditory Perception has been documented, the reverse influence has not been reported. In addition, previous reports of Unconscious cross-modal priming relied on procedures in which contamination of conscious processes could not be ruled out. We present the first report of Unconscious cross-modal priming when the unaware prime is auditory and the test stimulus is visual. We used the process-dissociation procedure [Debner, J. A., & Jacoby, L. L. (1994). Unconscious Perception: Attention, awareness and control. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20, 304-317] which allowed us to assess the separate contributions of conscious and Unconscious Perception of a degraded prime (either seen or heard) to performance on a visual fragment-completion task. Unconscious cross-modal priming (auditory prime, visual fragment) was significant and of a magnitude similar to that of Unconscious within-modality priming (visual prime, visual fragment). We conclude that cross-modal integration, at least between visual and auditory information, is more symmetrical than previously shown, and does not require conscious mediation.
Leon Y. Deouell - One of the best experts on this subject based on the ideXlab platform.
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Unconscious auditory information can prime visual word processing a process dissociation procedure study
Consciousness and Cognition, 2008Co-Authors: Dominique Lamy, Liad Mudrik, Leon Y. DeouellAbstract:Whether information perceived without awareness can affect overt performance, and whether such effects can cross sensory modalities, remains a matter of debate. Whereas influence of Unconscious visual information on auditory Perception has been documented, the reverse influence has not been reported. In addition, previous reports of Unconscious cross-modal priming relied on procedures in which contamination of conscious processes could not be ruled out. We present the first report of Unconscious cross-modal priming when the unaware prime is auditory and the test stimulus is visual. We used the process-dissociation procedure [Debner, J. A., & Jacoby, L. L. (1994). Unconscious Perception: Attention, awareness and control. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20, 304-317] which allowed us to assess the separate contributions of conscious and Unconscious Perception of a degraded prime (either seen or heard) to performance on a visual fragment-completion task. Unconscious cross-modal priming (auditory prime, visual fragment) was significant and of a magnitude similar to that of Unconscious within-modality priming (visual prime, visual fragment). We conclude that cross-modal integration, at least between visual and auditory information, is more symmetrical than previously shown, and does not require conscious mediation.
