The effect of a masked stimulus on the response to the masking stimulus

Abstract

Four experiments are reported in which the subjects had to respond to a target that masked a preceding prime via metacontrast masking. In one part of Experiment 1, the subjects discriminated the target's shape (square or diamond) by a motor-choice reaction, and in another part they had to respond with a simple reaction. The prime was neutral (circular) with respect to the target's shape. The data showed a facilitation effect. In both tasks the reaction time was reduced by the masked prime. However, the reduction was more pronounced with simple reaction than with choice reaction. In the other experiments, additional primes were used with the same angular shapes as the targets. In Experiments 2 and 3, after discriminating the target's shape by a choice reaction, the subjects had to judge the prime's shape in a signal-detection task. While neither the d' value for discriminating the angular primes from the circular ones (Exp. 2) nor the d' value for distinguishing between the angular primes (Exp. 3) was different from zero, the choice-reaction data showed a congruency effect. With a congruent prime (i.e., a prime that had the same shape as the target), the reaction times were reduced. With an incongruent prime, the reaction times grew. In Experiment 4 the errors were investigated. The facilitation effect was present in the RT, but not in the number of errors, whereas the congruency effect was present in the number, but not in the RT of errors. While the facilitation effect can be attributed either to an unspecific activation by the masked prime or to an influence of the prime on attentional processes, the congruency effect can be explained by the assumption that the masked prime directly activates the specific response, which corresponds to the prime's shape.

Motor activation with and without inhibition: Evidence for a threshold mechanism in motor control

“…In line with this hypothesis, evidence has been found that even stimuli presented near or below the threshold of conscious awareness can trigger response activation processes (Dehaene et al, 1999;Klotz & Wolff, 1995;Neumann & Klotz, 1994;Schwarz & Mecklinger, 1995). These phenomena have been attributed to the existence of direct perceptuomotor links (Neumann, 1990), which allow perceptual information to affect the motor system directly without necessarily being consciously perceived.…”

Mask-triggered thrust reversal in the negative compatibility effect

“…The time course of stimulus-triggered motor activation can be studied in response-priming tasks (Klotz & Neumann, 1999;Klotz & Wolff, 1995;Vorberg, Mattler, Heinecke, Schmidt, & Schwarzbach, 2003). In a typical response-priming task, participants perform a speeded response to a target stimulus that is preceded by a prime stimulus triggering either the same response as the target (consistent prime) or the opposite response (inconsistent prime).…”

Upper and lower visual field differences in perceptual asymmetries

“…If the target (the greyscales images) was presented briefly, and then a similarly shaped mask was presented following a short delay (see Klotz & Wolff, 1995 for example), it would strengthen the evidence in support of the task being purely attentional and not based on the participant"s memory of the image. It is recommended that a mask of similar shape be used as reaction times are typically faster and the number of errors is smaller when the target and the mask are congruent (Klotz & Wolff, 1995). This paradigm would eliminate concerns related to scanning and, more importantly, regarding mental representations that might have been formed.…”