Abstract
In daily life, individuals encounter visual stimuli that they desire to remember and others that they desire to not remember. However, voluntary regulation of memory encoding is asymmetrical across these opposite goals. While observers can directly up-regulate their memory encoding of desired stimuli, prior studies suggest that observers can only indirectly down-regulate their encoding of undesired stimuli by biasing their attentional resources towards other visual inputs. Here, we tested whether the ostensible inability to directly down-regulate memory encoding in the absence of stimulus competition could be resolved by increasing the predictability of upcoming regulatory demands. On every trial, participants were presented with a cue immediately before the onset of a real-world object that instructed them to remember (neutral), try “extra hard” to remember (up-regulate), or try to not remember (down-regulate) the object. However, in contrast to prior studies that varied the cue randomly from trial to trial, the cue was fixed across five consecutive trials before changing to a different instruction. Consistent with prior studies, we found that up-regulated objects were remembered better than neutrally-cued objects during subsequent memory testing. However, we also found that down-regulated objects were remembered worse than neutrally-cued objects and that down-regulation success did not vary across the trial run, suggesting that direct down-regulation was implemented rapidly in response to the first cue. Electrophysiological activity recorded during encoding revealed reduced P1 visually-evoked potentials elicited by the onset of down-regulated objects, implying that down-regulation was initiated by suppressing perceptual processing of the undesired stimuli. We also observed cascading effects of down-regulation on downstream processing as indicated by reductions in occipital alpha suppression and posterior positivity for down-regulated objects compared to neutrally-cued objects. Taken together, the present findings reveal an ability for observers to directly down-regulate their memory encoding of visual stimuli when demands to down-regulate are highly-predictable.