Research

What is the link between conscious awareness of a stimulus and its meaning? Several previous studies have reported that participants can extract the meaning from words and pictures that are below the “threshold of awareness” due to backward masking or diverted attention. For example, in the attentional blink paradigm (AB), people monitor a rapidly presented sequence of stimuli for the appearance of two targets. The first target is reported accurately but the second one is often missed, particularly if it occurs shortly after the first. This failure of awareness for the second target is thought to reflect the inability to pay attention to it when attention is still occupied with the first target. Several previous studies have reported that a “blinked” second target that is not present in awareness is still processed to the semantic level. The Hoffman lab has examined this issue in a series of studies using full color scenes as stimuli. Semantic priming was assessed using the N400 component of the event-related brain potential. Surprisingly, the results showed that blinked pictures do not show semantic priming effects suggesting that awareness may play a critical role in extracting meaning from scenes. We are continuing to examine whether these findings generalize to other visual stimuli such as objects and faces.

Researcher(s): Alyssa Lompado, Courtney Aul, Olivia Stibolt, Minwoo Kim, James E. Hoffman

EIB refers to impaired awareness of visual information appearing soon after presentation of a task-irrelevant, emotional picture (e.g., a threatening animal, a bloody face, etc.). Together with colleagues at the University of New South Wales in Australia, the Hoffman lab showed that this impaired awareness is related to brain activity in visual areas of the brain that occurs approximately a quarter of a second after presentation of the emotional picture. We are continuing to explore the mechanisms responsible for this fascinating phenomenon using ERP and behavioral methods.

Researcher(s): Alyssa Lompado, Minwoo Kim, Gus Baker, James E. Hoffman