In two experiments subjects attempted to identify words presented below the objective threshold using two task strategies emphasizing either allowing a word to pop into their heads or looking carefully at the stimulus field . Words were selected to represent both meaningful and structural dimensions. We also asked subjects to indicate their strategy preference and to rate their motivation to perform well. In the absence of conscious perception, both strategy preference and word meaning interacted with strategy condition, mediating the accuracy (...) of subjects′ direct word identification judgments. Motivation also mediated performance. Word structure had no effect. Unconscious perception manifested only in the pop condition, underscoring the importance of task strategy in determining whether subliminal effects are observed. A follow-up control experiment using sham flashes demonstrated that strategy preference and motivation effects were not artifacts resulting from performance feedback cues. (shrink)

Voluntary acts are preceded by electrophysiological (RPs). With spontaneous acts involving no preplanning, the main negative RP shift begins at about200 ms. Control experiments, in which a skin stimulus was timed (S), helped evaluate each subject's error in reporting the clock times for awareness of any perceived event.

The present study applies a new method for investigating dynamic unconscious processes. The method consists of selection of words from patient interview and test protocols that in the clinicians' judgments capture the patients' conscious symptom experience and the hypothetical unconscious conflict related to the symptom, subliminal and supraliminal presentation of these words, signal analysis of event-related potentials obtained to the word presentations. Eight phobics and three patients suffering from pathological grief reactions served as subjects. A time-frequency ERP analysis revealed that (...) subjects' ERPs classified the unconscious conflict words better subliminally than supraliminally, while the reverse was true for the conscious symptom words = 2.82, p = .011). The relationship between frequency and latency revealed a similar mirror image pattern for the unconscious conflict and conscious symptom words . This method demonstrated that objective, brain-based evidence for unconscious conflict can be obtained. (shrink)

Sensation elicited by a skin stimulus was subjectively reported to feel stronger when followed by a stimulus to somatosensory cerebral cortex , even when C was delayed by up to 400 ms or more. This expands the potentiality for retroactive effects beyond that previously known as backward masking. It also demonstrates that the content of a sensory experience can be altered by another cerebral input introduced after the sensory signal arrives at the cortex. The long effective S-C intervals support the (...) thesis that a duration of cortical activity of up to 0.5 s is required before awareness of a sensory stimulus is developed. (shrink)