Unconscious encoding and retrieval of events
PhD student: Sergej Wüthrich
Supervisors: Katrin Henke & Fred Mast (Psychology)
Episodic memory is the memory for personally experienced events and their temporal‐spatial context and it is traditionally conceived as an exclusively conscious form of long‐term memory. According to this view we need to consciously encode episodic information to retrieve it later and to consciously recollect this information to express it. However based on recent studies we doubt that consciousness is the critical factor to divide between memory systems. Instead memory systems divide on the basis of computation requirements imposed by the encoding and the retrieval situation. We believe that whenever the rapid and flexible encoding of new associations is required the episodic memory network will be called on – irrespective of the level of consciousness of encoding or retrieval. To test this hypothesis we conducted two experiments which involved subliminal (i.e. consciously not detectable) learning material and later retrieval tests of this material. In the first experiment participants were tested on unconscious object-location memory which emphasized the spatial component of episodic memory. In the second experiment participants were tested on unconscious temporal-spatial integration of information. Both experiments showed evidence of unconscious knowledge during retrieval testing, either through eye movements or forced-choice decisions (experiment 1) or through decision times (experiment 2). This further supports theoretical claims that memory systems divide on the computational demands imposed by a learning/retrieval situation rather than consciousness.
The development of the experimental designs, pilot testing, data collection and data analysis started in August 2013 and ended in June 2016.