Figure 1

Experimental Design, Memory Performance and Pupillary Changes. (a) Participants encoded 3 words from the same semantic category, engaged in a distracter task and were in a retrieval phase to orally recall the 3 words. This procedure was repeated over 4 cycles. Retrieval commenced with an initiation phase and a response phase. The initiation phase was indicated by a “?” in the center of the screen and the response phase was indicated with a speaker symbol in the center of the screen. Participants were not allowed to respond until the response phase was initiated. The distracter task was to orally count backwards in steps of 7 from a randomly generated three-digit number. In the fourth and final word list, proactive interference from previous word lists continued to build up in the PI condition (middle panel), whereas a release from proactive interference was created by changing the semantic category in the RPI condition (right panel). The semantic categories “furniture” and “metals” are here used to illustrate a possible cycle for both PI and RPI conditions, whereas in the actual experiment all categories were used equally often in all conditions across participants. (b) Average retrieval score for word lists 1–3 and for the fourth and final word list when separated into PI and RPI conditions. (c) Average pupil change in mm (compared to baseline) for word lists 1–3 and for the fourth and final word list when separated into PI and RPI conditions. Error bars denote SEM, **p < 0.01, ***p < 0.001.