Sunday, October 02nd, 2011 [17:00 - 18:00]
OS_42.1 - Gaining access to conscious perception
Chica, A. 1 , Botta, F. 2 , Lupiáñez, J. 2 & Bartolomeo, P. 1
1 INSERM-UPMC UMR-S 975
2 Universidad de Granada
The relationship between spatial attention and conscious perception (CP) remains highly controversial. While theoretical models and experimental data support their interdependence (Chica et al., 2010; 2011; Dehaene et al., 2006; Mack & Rock, 1998), recent studies claim that at least some forms of attention -endogenous or top down spatial attention- are neither sufficient nor necessary for CP (Koch & Tsuchiya, 2007). We will present an electrophysiological study in which endogenous and exogenous orienting mechanisms are orthogonally manipulated from CP. By analyzing two different cue-related components, our results demonstrated that while endogenous attention was electrophysiologically dissociated from CP, exogenous attention was not. Additionally, targets elicited a larger N100 component when they were presented at unattended vs. attended locations, independently of conscious reports. Our results therefore support previous claims of dissociations between some forms of spatial attention and CP, but also highlight the importance of exogenous orienting on the selection of information for conscious access.
OS_42.2 - Comparing measures of consciousness in an artificial grammar learning task
Wierzchon, M. 1, 2 , Asanowicz, D. 1 & Cleeremans, A. 2
1 Institute of Psychology, Jagiellonian University, Krakow, Poland
2 Consciousness, Cognition & Computation Group, Université Libre de Bruxelles, Belgium
Consciousness can be measured in different ways, and different measures unfortunately often yield different conclusions about the extent to which awareness relates to performance. The challenge of correctly identifying which measure is best is thus substantial. Here, we compare five different subjective measures of rule awareness in the context of an artificial grammar learning task. Participants (N=217) had to express their rule awareness by means of one of five different scales: confidence rating (CR), post-decision wagering (PDW), rule awareness (RAS, a modified PAS scale), the Sergent-Dehaene continuous scale (SDS), and feeling of warmth (FOW, a new measure). All scales were found equally sensitive to conscious knowledge, but PDW and SDS are affected by risk aversion (suggesting that CR, RAS, and our new scale FOW should be preferred). We observed that CR captures the largest range of states of consciousness (yielding the largest difference in accuracy between the highest and lowest scale points), but also that only CR fails to indicate unconscious knowledge by means of the guessing criterion (chance performance when guessing). CR’s unique features suggest that it may be used in conjunction with RAS or FOW to enable finer assessment of subjective states of awareness.
OS_42.3 - How to measure unconscious perception? A trial-based assessment approach
Van den Bussche, E. 1 & Reynvoet, B. 2
1 Department of Psychology. Vrije Universiteit Brussel. Brussels, Belgium
2 Department of Psychology. Katholieke Universiteit Leuven. Leuven, Belgium
Unconscious processing can reach a sophisticated cognitive level. Therefore, researchers have recently been investigating what distinguishes conscious and unconscious processing. However, many of these studies suffer from critical problems. First, objective tests were used to assess prime visibility, which are heavily debated. Second, the visual strength of the stimuli critically differed in the conscious and unconscious conditions. Third, different experimental paradigms were used, making studies difficult to compare. We therefore developed a paradigm to measure unconscious perception avoiding these problems. A Stroop priming design is used, but additionally participants have to indicate on each trial how certain they are about the identity of the prime using a five-point PAS scale. Critically, this design avoids previous methodological problems: a subjective assessment of prime awareness on a single-trial basis is used; conscious and unconscious trials are separated based on the prime awareness measure, guaranteeing the same stimulus strength in both conditions; this design can be used to study a range of cognitive effects, making results more easily comparable. A series of pilot studies were conducted to optimize this paradigm. Importantly, we observed Stroop priming for both conscious and unconscious trials, making this design a fruitful approach to measuring unconscious perception.