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Electrophysiological activation by masked primes: Independence of prime-related and target-related activities.

Klotz W, Heumann M, Ansorge U, Neumann O - Adv Cogn Psychol (2008)

Bottom Line: Visual stimuli that are made invisible by metacontrast masking (primes) have a marked influence on behavioral and psychophysiological measures such as reaction time (RT) and the lateralized readiness potential (LRP). 4 experiments are reported that shed light on the effects that masked primes have on the LRP.Participants had a go-nogo task in which the prime was associated with 1 of 2 responses even if the target required participants to refrain from responding.The results demonstrated that (a) masked primes activate responses even in a nogo situation, (b) this prime-related activation is independent of masking, (c) and is also independent of whether prime and target require the same responses (congruent condition) or different responses (incongruent condition).

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Bielefeld, Bielefeld, Germany.

ABSTRACT
Visual stimuli that are made invisible by metacontrast masking (primes) have a marked influence on behavioral and psychophysiological measures such as reaction time (RT) and the lateralized readiness potential (LRP). 4 experiments are reported that shed light on the effects that masked primes have on the LRP. Participants had a go-nogo task in which the prime was associated with 1 of 2 responses even if the target required participants to refrain from responding. To analyze the electrophysiological responses, we computed the LRP and applied an averaging method separating the activation due to the prime and the target. The results demonstrated that (a) masked primes activate responses even in a nogo situation, (b) this prime-related activation is independent of masking, (c) and is also independent of whether prime and target require the same responses (congruent condition) or different responses (incongruent condition).

No MeSH data available.


Sequence of stimulus events. The left half depicts an incongruent trial: The								arrangement of the figures in the target pair is reversed with respect to								the prime. The right half shows a masked nogo trial. In both cases, the								diamond is assumed to be the target. Numbers designate stimulus								duration.
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Figure 1: Sequence of stimulus events. The left half depicts an incongruent trial: The arrangement of the figures in the target pair is reversed with respect to the prime. The right half shows a masked nogo trial. In both cases, the diamond is assumed to be the target. Numbers designate stimulus duration.

Mentions: One basic paradigm in the study of unconscious information processing is the metacontrast dissociation (see Figure 1; see also Klotz & Neumann, 1999; Klotz & Wolff, 1995; Neumann & Klotz, 1994). In this paradigm, participants have a two-choice reaction time (RT) task. In each trial they see a square and a diamond (a square rotated by 45°). One of these shapes is defined as the target, and participants are told to press the right button when the target appears on the right side of a monitor and the left button when it appears on the left side. The other shape serves as a distractor. Unknown to the participants, invisible primes are presented prior to the visible target-distractor pair. The shapes of the primes and the targets are designed so that the targets mask the primes by metacontrast masking (for examples and an explanation of metacontrast masking, see Breitmeyer, 1984; Breitmeyer & Ogmen, 2000, 2006).


Electrophysiological activation by masked primes: Independence of prime-related and target-related activities.

Klotz W, Heumann M, Ansorge U, Neumann O - Adv Cogn Psychol (2008)

Sequence of stimulus events. The left half depicts an incongruent trial: The								arrangement of the figures in the target pair is reversed with respect to								the prime. The right half shows a masked nogo trial. In both cases, the								diamond is assumed to be the target. Numbers designate stimulus								duration.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864997&req=5

Figure 1: Sequence of stimulus events. The left half depicts an incongruent trial: The arrangement of the figures in the target pair is reversed with respect to the prime. The right half shows a masked nogo trial. In both cases, the diamond is assumed to be the target. Numbers designate stimulus duration.
Mentions: One basic paradigm in the study of unconscious information processing is the metacontrast dissociation (see Figure 1; see also Klotz & Neumann, 1999; Klotz & Wolff, 1995; Neumann & Klotz, 1994). In this paradigm, participants have a two-choice reaction time (RT) task. In each trial they see a square and a diamond (a square rotated by 45°). One of these shapes is defined as the target, and participants are told to press the right button when the target appears on the right side of a monitor and the left button when it appears on the left side. The other shape serves as a distractor. Unknown to the participants, invisible primes are presented prior to the visible target-distractor pair. The shapes of the primes and the targets are designed so that the targets mask the primes by metacontrast masking (for examples and an explanation of metacontrast masking, see Breitmeyer, 1984; Breitmeyer & Ogmen, 2000, 2006).

Bottom Line: Visual stimuli that are made invisible by metacontrast masking (primes) have a marked influence on behavioral and psychophysiological measures such as reaction time (RT) and the lateralized readiness potential (LRP). 4 experiments are reported that shed light on the effects that masked primes have on the LRP.Participants had a go-nogo task in which the prime was associated with 1 of 2 responses even if the target required participants to refrain from responding.The results demonstrated that (a) masked primes activate responses even in a nogo situation, (b) this prime-related activation is independent of masking, (c) and is also independent of whether prime and target require the same responses (congruent condition) or different responses (incongruent condition).

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Bielefeld, Bielefeld, Germany.

ABSTRACT
Visual stimuli that are made invisible by metacontrast masking (primes) have a marked influence on behavioral and psychophysiological measures such as reaction time (RT) and the lateralized readiness potential (LRP). 4 experiments are reported that shed light on the effects that masked primes have on the LRP. Participants had a go-nogo task in which the prime was associated with 1 of 2 responses even if the target required participants to refrain from responding. To analyze the electrophysiological responses, we computed the LRP and applied an averaging method separating the activation due to the prime and the target. The results demonstrated that (a) masked primes activate responses even in a nogo situation, (b) this prime-related activation is independent of masking, (c) and is also independent of whether prime and target require the same responses (congruent condition) or different responses (incongruent condition).

No MeSH data available.