The extent and specificity of visual exploration determines the formation of recollected memories in complex scenes.

Our visual memories of complex scenes often appear as robust, detailed records of the past. Several studies have demonstrated that active exploration with eye movements improves recognition memory for scenes, but it is unclear whether this improvement is due to stronger feelings of familiarity or more detailed recollection. We related the extent and specificity of fixation patterns at encoding and retrieval to different recognition decisions in an incidental memory paradigm. After incidental encoding of 240 real-world scene photographs, participants (N = 44) answered a surprise memory test by reporting whether an image was new, remembered (indicating recollection), or just known to be old (indicating familiarity). To assess the specificity of their visual memories, we devised a novel report procedure in which participants selected the scene region that they specifically recollected, that appeared most familiar, or that was particularly new to them. At encoding, when considering the entire scene,subsequently recollected compared to familiar or forgotten scenes showed a larger number of fixations that were more broadly distributed, suggesting that more extensive visual exploration determines stronger and more detailed memories. However, when considering only the memory-relevant image areas, fixations were more dense and more clustered for subsequently recollected compared to subsequently familiar scenes. At retrieval, the extent of visual exploration was more restricted for recollected compared to new or forgotten scenes, with a smaller number of fixations. Importantly, fixation density and clustering was greater in memory-relevant areas for recollected versus familiar or falsely recognized images. Our findings suggest that more extensive visual exploration across the entire scene, with a subset of more focal and dense fixations in specific image areas, leads to increased potential for recollecting specific image aspects.

Exploitation of local and global information in predictive processing.

While prediction errors have been established to instigate learning through model adaptation, recent studies have stressed the role of model-compliant events in predictive processing. Specifically, probabilistic information at critical points in time (so-called checkpoints) has been suggested to be sampled in order to evaluate the internal model, particularly in uncertain contexts. This way, initial model-based expectations are iteratively reaffirmed under uncertainty, even in the absence of prediction errors. Using electroencephalography (EEG), the present study aimed to investigate the interplay of such global uncertainty information and local adjustment cues prompting on-line adjustments of expectations. Within a stream of single digits, participants were to detect ordered sequences (i.e., 3-4-5-6-7) that had a regular length of five digits and were occasionally extended to seven digits. Over time, these extensions were either rare (low irreducible uncertainty) or frequent (high uncertainty) and could be unexpected or indicated by incidental colour cues. Accounting for cue information, an N400 component was revealed as the correlate of locally unexpected (vs expected) outcomes, reflecting effortful integration of incongruous information. As for model-compliant information, multivariate pattern decoding within the P3b time frame demonstrated effective exploitation of local (adjustment cues vs non-informative analogues) and global information (high vs low uncertainty regular endings) sampled from probabilistic events. Finally, superior fit of a global model (disregarding local adjustments) compared to a local model (including local adjustments) in a representational similarity analysis underscored the precedence of global reference frames in hierarchical predictive processing. Overall, results suggest that just like error-induced model adaptation, model evaluation is not limited to either local or global information. Following the hierarchical organisation of predictive processing, model evaluation too can occur at several levels of the processing hierarchy.

Enhanced recognition of memorable pictures in ultra-fast RSVP.

Long-term recognition memory for some pictures is consistently better than for others (Isola, Xiao, Parikh, Torralba, & Oliva, IEEE Transaction on Pattern Analysis and Machine Intelligence (PAMI), 36(7), 1469-1482, 2014). Here, we investigated whether pictures found to be memorable in a long-term memory test are also perceived more easily when presented in ultra-rapid RSVP. Participants viewed 6 pictures they had never seen before that were presented for 13 to 360 ms per picture in a rapid serial visual presentation (RSVP) sequence. In half the trials, one of the pictures was a memorable or a nonmemorable picture and perception of this picture was probed by a visual recognition test at the end of the sequence. Recognition for pictures from the memorable set was higher than for those from the nonmemorable set, and this difference increased with increasing duration. Nonmemorable picture recognition was low initially, did not increase until 120 ms, and never caught up with memorable picture recognition performance. Thus, the long-term memorability of an image is associated with initial perceptibility: A picture that is hard to grasp quickly is hard to remember later.

Self-Reported Stickiness of Mind-Wandering Affects Task Performance.

When asked to perform a certain task, we typically spend a decent amount of time thinking thoughts unrelated to that task-a phenomenon referred to as "mind-wandering." It is thought that this mind-wandering is driven at least in part by our unfinished goals and concerns. Previous studies have shown that just after presenting a participant with their own concerns, their reports of task-unrelated thinking increased somewhat. However, effects of these concerns on task performance were somewhat inconsistent. In this study we take the opposite approach, and examine whether task performance depends on the self-reported thought content. Specifically, a particularly intriguing aspect of mind-wandering that has hitherto received little attention is the difficulty of disengaging from it, in other words, the "stickiness" of the thoughts. While presenting participants with their own concerns was not associated with clear effects on task performance, we showed that the reports of off-task thinking and variability of response times increased with the amount of self-reported stickiness of thoughts. This suggests that the stickiness of mind-wandering is a relevant variable, and participants are able to meaningfully report on it.