Motor activation without conscious discrimination in metacontrast masking.

Abstract

Nine experiments investigated motor responses to geometric stimuli (a target and a distractor) preceded by masked primes. In congruent trials, the target was preceded by a smaller target-like shape and the distractor by a smaller distractor-like shape. In incongruent trials this arrangement was reversed. In neutral trials both primes were distractor-like shapes. Highly significant effects of these priming conditions on reaction time and error rate were found, although there was no conscious discrimination of primes, as assessed by a discrimination index (d' or d s ) not different from 0. This result subsisted under conditions of time pressure, feedback, practice, and financial incentive in the discrimination task. It remained unchanged under conditions in which the reaction time and discrimination tasks were blocked, alternated, randomly mixed, or combined on each trial. It is concluded that motor activation without conscious discrimination was demonstrated.A Note on Terminology Among the terms that have been used to denote this research area are subliminal perception, unconscious perception, and perception without awareness. There are two reasons why we believe that these terms are better avoided.

Incidental learning of S-R contingencies in the masked prime task.

“…Of note, this was true even for free-choice blocks that immediately followed mixed blocks: No carryover effects from the previously relevant arrows were observed when participants were not explicitly instructed to respond to arrows . Corresponding results have been obtained in a number of different motor priming tasks employing the metacontrast paradigm (e.g., Ansorge et al, 2002;Klotz & Neumann, 1999;Kunde et al, 2003), suggesting that the instruction dependency of subliminal motor priming effects is not paradigm specific but reflects a fundamental feature of the underlying perceptuo-motor control processes.…”

Different time courses for visual perception and action priming

“…To prevent indirect priming effects on recognition, subjects were to respond at least 600 ms after the mask. Given that speed stress invariably reduces response accuracy (16), delayed responding should also provide optimal conditions for recognition performance (13). Other details are as in c.…”

“…First, simple reactions to the mask are speeded up by undetected primes (12). Second, unrecognized primes facilitate or inhibit choice reactions to the mask if prime and mask share stimulus attributes critical for the correct or the alternative response (6,13).…”

Consequences of display changes during interrupted visual search: Rapid resumption is target specific

“…In typical masked priming studies, participants are asked to view a rapid sequence of three items: a brief prime item, followed by an overlapping mask item, which is in turn followed by the target item. By manipulating the prime-mask relationship along geometric, temporal and spatial similarity factors, experimenters can find conditions in which participants never become aware of the prime identity (as indicated by chance performance in a prime identification task), yet the prime identity significantly impacts target identification processes (e.g., Eimer & Schlaghecken, 2002;Klapp & Hinkley, 2002;Klotz & Neumann, 1999;Lleras & Enns, 2004Vorberg et al, 2003). Therefore, it is entirely likely that having represented (to some extent) response-relevant information in the yet unconfirmed perceptual hypothesis, this information may find a way of unconsciously activating associated motor responses, just as unconfirmed perceptual hypotheses seem to do in masked priming.…”