Detecting analogies unconsciously.
Analogies may arise from the conscious detection of similarities between a present and a past situation. In this functional magnetic resonance imaging study, we tested whether young volunteers would detect analogies unconsciously between a current supraliminal (visible) and a past subliminal (invisible) situation. The subliminal encoding of the past situation precludes awareness of analogy detection in the current situation. First, participants encoded subliminal pairs of unrelated words in either one or nine encoding trials. Later, they judged the semantic fit of supraliminally presented new words that either retained a previously encoded semantic relation ("analog") or not ("broken analog"). Words in analogs versus broken analogs were judged closer semantically, which indicates unconscious analogy detection. Hippocampal activity associated with subliminal encoding correlated with the behavioral measure of unconscious analogy detection. Analogs versus broken analogs were processed with reduced prefrontal but enhanced medial temporal activity. We conclude that analogous episodes can be detected even unconsciously drawing on the episodic memory network.
Department of Psychology, University of Bern , Bern , Switzerland ; Center for Cognition, Learning and Memory, University of Bern , Bern , Switzerland.
Thomas P
TP
Reber
Institute for Biomedical Engineering, ETH Zurich , Zurich , Switzerland.
Roger
R
Luechinger
Institute for Biomedical Engineering, ETH Zurich , Zurich , Switzerland.
Peter
P
Boesiger
Department of Psychology, University of Bern , Bern , Switzerland ; Center for Cognition, Learning and Memory, University of Bern , Bern , Switzerland.
Katharina
K
Henke
analogical mapping; consciousness; episodic memory; flexibility; hippocampus; medial temporal lobe; subliminal