A full list of publications, and PDFs for each paper, can be found at michellemramey.com/publications.
The main topics we investigate in the lab, and some of our findings under each, are outlined below.
Characterizing familiarity-based memory
Why is it that we can recognize someone, but not remember where we know them from? This phenomenon is driven by familiarity, a recognition process that supports vague, gist-like memory. Vivid, detailed recollection is quite well understood, but familiarity is much more mysterious; it is typically measured as any recognition occurring without recollection. There are many competing theories for what familiarity is, how it functions, and the extent to which it differs from unconscious memory.
We aim to develop new paradigms and methods for probing familiarity-based memory to further our understanding of the mechanisms giving rise to it. So far, we have found that:
- Recollection and unconscious memory guide attention during visual search, but familiarity does not.
- Ramey et al., 2019; Cognition
- Ramey et al., under review
- Familiarity reduces the effects of schemas on memory decisions, and exhibits a trade-off with semantic meaning in predicting gaze reinstatement (retracing your visual steps) between study and test.
- Older adults’ familiarity-based memory is slightly more precise than younger adults’.
- The spatial distribution of eye movements during encoding and retrieval predict familiarity strength, whereas unconscious memory does not exhibit analogous effects.
Interactions between memory and visual attention
The eye movement patterns we make when viewing visual information, during both encoding and retrieval, appear to be critical for our ability to remember it. Our memory also exerts a strong influence on our eye movements.
We investigate these bidirectional interactions in a variety of domains, with the primary goal of understanding memory functioning itself. We focus on three functionally distinct memory processes: recollection, familiarity, and unconscious memory.
So far, we have found:
- Recollection and unconscious memory guide visual search through distinct eye movement patterns.
- Ramey et al., 2019; Cognition
- Ramey et al., under review
- More dispersed eye movements at encoding, and more clustered eye movements at retrieval, predict familiarity strength.
- Refixating the same regions at study and test (gaze reinstatement) relates to stronger familiarity.
- Gaze reinstatement is more strongly related to semantic meaning than memory, despite longstanding theories that refixations reflect memory.
- Distinct processes underpinning change detection (conscious versus unconscious) are related to distinct patterns of eye movements.
Interactions between memory and schema knowledge
Our general knowledge of the world, in the form of schemas, has a strong influence on our memories. For example, if something violates our schemas (e.g., if we last put our keys in an unusual place, and are trying to remember where they are), we are more likely to struggle to remember it than if something is in line with our schemas (e.g., keys in typical place).
We aim to understand the mechanisms underlying these effects, particularly in terms of the extent to which effects occur during encoding or retrieval, and which memory processes are involved.
Currently, our projects mainly focus on how schemas bias our memory decisions, working from a Bayesian reconstruction framework. So far, we have found:
- Schemas bias our memories primarily when our underlying memory is weak. Unconscious memory, familiarity, and recollection each reduce the effects of schemas on spatial recall accuracy, with recollection often abolishing schema effects entirely.
- Schemas differentially interact with different memory processes to guide eye movements.
- Ramey et al., under review
Changes with aging
Given that memory, visual attention, and the use of schema knowledge change as we get older, we have recently begun investigating the topics above with respect to cognitive aging as well. Our goal is to understand not only what aspects of memory are impaired in older age, but also what aspects may be improved with age; for example, how the aging brain might strategically leverage the fact that knowledge increases with age.
So far, we have found:
- Older adults rely more on schema knowledge when making memory decisions, such that schema knowledge compensates for losses in memory precision.
- Eating a diet more consistent with a plant-based diet predicts better memory and executive functioning in older adults.
Developing new eye movement measures
In addition to advancing theory, we aim to develop new ways to probe cognitive processes using eyetracking within memory and beyond. One guiding goal is to try to create alternatives to standard measures that have been based on experimenter-selected cutoffs or parameters (e.g., counting all fixations within 2 degrees as a refixation; dividing scenes into arbitrary numbers of regions) by developing novel continuous measures that don’t include researcher degrees of freedom, in order to improve replicability of results.
So far, we have developed new measures of:
- Spatial dispersion
- Viewing of global changes
- Reinstatement and refixation
- First saccade accuracy during search
- Ramey et al., 2019; Cognition
- Ramey et al., under review
- Fixation-level drift towards the target during search