Seamless Cognition: Visual Processing at the Intersection of Different Cognitive Faculties

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The seamless integration of different cognitive faculties (i.e., perception, attention, visual short-term memory - VSTM, long-term memory - LTM), is one of the hallmarks of the human mind's sophistication. Much progress has been made in understanding these processes in isolation but knowledge about how they intersect is limited.For example, visual LTM and VSTM have the same limit on representational precision but it is unclear if the same factors contribute to the precision of representations across LTM and VSTM. My lab has tested issues around memory precision and accessibility by studying the process of memory interference: the disruption of task-relevant processing by competing information. In LTM research, the similarity assumption holds that one's degree of memory impairment increases with the similarity between interfering information and memory contents. Memory impairments come in different flavors; following interference, studied information may be retained with degraded precision or erased completely.Prior studies lacked the resolution to disentangle these two alternatives, as they used discrete, forced-choice responses. Using a continuous free-recall task with mixture modeling to estimate the separate contributions of erasing and degrading, we found that interference from highly dissimilar items resulted in memory erasure and that interference from items of intermediate similarity degraded memory's precision. Participants typically resisted interference from highly similar items. Thus we demonstrated that the similarity assumption does not hold universally: the nature of visual similarity may tip the balance towards sacrificing memory precision in favor of memory accessibility, or vice versa. I am now proposing a novel program of study that will uncover how different aspects of cognition inform each other. I am proposing that attending to a specific value in colour space enhances the processing of that value and attenuates the processing of highly-similar but nonidentical colour values, akin to surround suppression. In a related line of work, we will show that the detection of task-irrelevant novelty will modulate VSTM precision. Finally, we will use an ensemble statistics approach to show that early visual cortex can represent unseen objects. My trainees and I will test our hypotheses behaviourally and with different neuroimaging approaches (e.g., EEG and fMRI).The overarching goal of this program of research is to identify the foundational cognitive and neural processes that enable seamless cognition. Rarely does our subjective experience highlight a switch from one cognitive faculty to another; instead, we effortlessly access various cognitive operations across different timescales. These different cognitive faculties may have opposing or complementary processing biases. We will show how these processes mutually accentuate or attenuate each other.