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Measuring unconscious cognition: Beyond the zero-awareness criterion.

Schmidt T - Adv Cogn Psychol (2008)

Bottom Line: This paper discusses two different lines of attack for establishing unconscious cognition in such experiments.In particular, it is argued here that priming effects in speeded pointing movements (Schmidt, Niehaus, & Nagel, 2006) occur in the absence of the recurrent processing that is often assumed to be a necessary condition for awareness (for instance, DiLollo, Enns, & Rensink, 2000; Lamme & Roelfsema, 2000).Feedforward tasks such as this might thus be used to measure the time-course of unconscious processing directly, before intracortical feedback and awareness come into play.

View Article: PubMed Central - PubMed

Affiliation: Department of Cognitive Psychology, University of Giessen, Germany.

ABSTRACT
Visual masking can be employed to manipulate observers' awareness of critical stimuli in studies of masked priming. This paper discusses two different lines of attack for establishing unconscious cognition in such experiments. Firstly, simple dissociations between direct measures (D) of visual awareness and indirect measures (I) of processing per se occur when I has some nonzero value while D is at chance level; the traditional requirement of zero awareness is necessary for this criterion only. In contrast, double dissociations occur when some experimental manipulation has opposite effects on I and D, for instance, increasing priming effects despite decreasing prime identification performance (Schmidt & Vorberg, 2006). Double dissociations require much weaker measurement assumptions than other criteria. An attractive alternative to this dissociation approach would be to use tasks that are known to violate necessary conditions of visual awareness altogether. In particular, it is argued here that priming effects in speeded pointing movements (Schmidt, Niehaus, & Nagel, 2006) occur in the absence of the recurrent processing that is often assumed to be a necessary condition for awareness (for instance, DiLollo, Enns, & Rensink, 2000; Lamme & Roelfsema, 2000). Feedforward tasks such as this might thus be used to measure the time-course of unconscious processing directly, before intracortical feedback and awareness come into play.

No MeSH data available.


Related in: MedlinePlus

Priming effects in pointing movements in the mask identification task of						Schmidt et al. (2006).						a) Low-contrast color conditions. b) High-contrast						color conditions. Note that the time axis is locked to prime onset while the						possible times of mask onsets are indicated by the stippled vertical lines.						Priming effects were calculated by subtracting finger positions in						consistent and inconsistent trials. Vertical bars correspond to						within-subject standard errors at several points in time, pooled across						subjects. Note that in both color contrast conditions, the initial						time-course of priming is identical for all SOAs and both mask types,						strongly suggesting that early priming effects exclusively depend on						properties of the prime but are independent of all mask characteristics.						Adapted from Schmidt et al. (2006).
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Figure 4: Priming effects in pointing movements in the mask identification task of Schmidt et al. (2006). a) Low-contrast color conditions. b) High-contrast color conditions. Note that the time axis is locked to prime onset while the possible times of mask onsets are indicated by the stippled vertical lines. Priming effects were calculated by subtracting finger positions in consistent and inconsistent trials. Vertical bars correspond to within-subject standard errors at several points in time, pooled across subjects. Note that in both color contrast conditions, the initial time-course of priming is identical for all SOAs and both mask types, strongly suggesting that early priming effects exclusively depend on properties of the prime but are independent of all mask characteristics. Adapted from Schmidt et al. (2006).

Mentions: To assess the validity of the crucial third criterion (the response’s initial independence of the mask stimulus), we derived a spatial measure of the priming effect by subtracting the finger positions in consistent and inconsistent trials. (This measure tells us how far the finger position in inconsistent trials lags behind the finger position in consistent trials at corresponding points in time.) For both high-contrast and low-contrast color stimuli, spatial priming effects started to develop at a time locked to prime onset, and priming effects became larger for longer SOAs and weaker masks (Figure 4). Strikingly, however, all these priming functions were initially the same, neatly conforming to our third rapid-chase criterion: The early time-courses of priming were virtually identical for all combinations of mask type and SOA, exclusively depending on characteristics of the prime but being completely independent of all mask characteristics.7


Measuring unconscious cognition: Beyond the zero-awareness criterion.

Schmidt T - Adv Cogn Psychol (2008)

Priming effects in pointing movements in the mask identification task of						Schmidt et al. (2006).						a) Low-contrast color conditions. b) High-contrast						color conditions. Note that the time axis is locked to prime onset while the						possible times of mask onsets are indicated by the stippled vertical lines.						Priming effects were calculated by subtracting finger positions in						consistent and inconsistent trials. Vertical bars correspond to						within-subject standard errors at several points in time, pooled across						subjects. Note that in both color contrast conditions, the initial						time-course of priming is identical for all SOAs and both mask types,						strongly suggesting that early priming effects exclusively depend on						properties of the prime but are independent of all mask characteristics.						Adapted from Schmidt et al. (2006).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864967&req=5

Figure 4: Priming effects in pointing movements in the mask identification task of Schmidt et al. (2006). a) Low-contrast color conditions. b) High-contrast color conditions. Note that the time axis is locked to prime onset while the possible times of mask onsets are indicated by the stippled vertical lines. Priming effects were calculated by subtracting finger positions in consistent and inconsistent trials. Vertical bars correspond to within-subject standard errors at several points in time, pooled across subjects. Note that in both color contrast conditions, the initial time-course of priming is identical for all SOAs and both mask types, strongly suggesting that early priming effects exclusively depend on properties of the prime but are independent of all mask characteristics. Adapted from Schmidt et al. (2006).
Mentions: To assess the validity of the crucial third criterion (the response’s initial independence of the mask stimulus), we derived a spatial measure of the priming effect by subtracting the finger positions in consistent and inconsistent trials. (This measure tells us how far the finger position in inconsistent trials lags behind the finger position in consistent trials at corresponding points in time.) For both high-contrast and low-contrast color stimuli, spatial priming effects started to develop at a time locked to prime onset, and priming effects became larger for longer SOAs and weaker masks (Figure 4). Strikingly, however, all these priming functions were initially the same, neatly conforming to our third rapid-chase criterion: The early time-courses of priming were virtually identical for all combinations of mask type and SOA, exclusively depending on characteristics of the prime but being completely independent of all mask characteristics.7

Bottom Line: This paper discusses two different lines of attack for establishing unconscious cognition in such experiments.In particular, it is argued here that priming effects in speeded pointing movements (Schmidt, Niehaus, & Nagel, 2006) occur in the absence of the recurrent processing that is often assumed to be a necessary condition for awareness (for instance, DiLollo, Enns, & Rensink, 2000; Lamme & Roelfsema, 2000).Feedforward tasks such as this might thus be used to measure the time-course of unconscious processing directly, before intracortical feedback and awareness come into play.

View Article: PubMed Central - PubMed

Affiliation: Department of Cognitive Psychology, University of Giessen, Germany.

ABSTRACT
Visual masking can be employed to manipulate observers' awareness of critical stimuli in studies of masked priming. This paper discusses two different lines of attack for establishing unconscious cognition in such experiments. Firstly, simple dissociations between direct measures (D) of visual awareness and indirect measures (I) of processing per se occur when I has some nonzero value while D is at chance level; the traditional requirement of zero awareness is necessary for this criterion only. In contrast, double dissociations occur when some experimental manipulation has opposite effects on I and D, for instance, increasing priming effects despite decreasing prime identification performance (Schmidt & Vorberg, 2006). Double dissociations require much weaker measurement assumptions than other criteria. An attractive alternative to this dissociation approach would be to use tasks that are known to violate necessary conditions of visual awareness altogether. In particular, it is argued here that priming effects in speeded pointing movements (Schmidt, Niehaus, & Nagel, 2006) occur in the absence of the recurrent processing that is often assumed to be a necessary condition for awareness (for instance, DiLollo, Enns, & Rensink, 2000; Lamme & Roelfsema, 2000). Feedforward tasks such as this might thus be used to measure the time-course of unconscious processing directly, before intracortical feedback and awareness come into play.

No MeSH data available.


Related in: MedlinePlus