Working memory errors from distraction are not influenced by sensory noise at encoding

Prior research suggests that ongoing sensory input during the delay period of a visual working memory task interferes with the storage of remembered information. However, it is unclear whether sensory uncertainty during encoding increases susceptibility to interference or whether memories are relatively stable once information is encoded (even if encoding is highly inaccurate). Here, we tested whether distracting stimuli influenced memory accuracy while simultaneously manipulating sensory noise by changing the width of a bandpass filter applied to white noise stimuli to titrate the amount of orientation information in each remembered stimulus. In a behavioral experiment (N=24), participants viewed a phase-reversing orientation grating rendered at one of two levels of sensory noise (high and low) for 500 ms, followed by a 3,000 ms delay with one of three distractor conditions (no distractor, ignore oriented white noise distractor, or attend oriented white noise distractor). At the end of each trial subjects responded by rotating a white line to match the remembered orientation. We found strong evidence that increasing noise in the remembered oriented grating decreased working memory performance (BF10=3.49e12). Notably, the presence of oriented distractors interfered with working memory performance (BF10=72.2), with evidence of memory attraction toward the orientation of the noise distractor. However, there was no interaction between stimulus noise and distractor presence (BF10=0.13). These data provide evidence that while working memory representations are prone to adaptive distortions during delay periods, these distortions are not modulated by sensory noise during encoding.