Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (4 results)

  • Article
  • Peer Reviewed
Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 38 (2016)
How much do individuals, compared to the population, knowabout the distribution of values in the world? Participantsreported the prices of consumer goods such as watches andbelts and we compared how accurately individuals vs. theoverall population knew the mean and dispersion of prices.Although individuals and the population both knew objects’average prices and relative standard deviations, the populationwas more sensitive to the absolute standard deviation ofprices. In a second experiment, we examined whetherindividuals’ impoverished distribution knowledge impairstheir ability to interpret advertisements. Consistent withpeople using Bayesian inference, the higher an object’s actualprice dispersion, the more participants relied onadvertisements; however, this effect is considerably smallerthan a simple proportional offset, suggesting again thatindividuals underestimate dispersion. Thus, despite having asense of the distribution of real world quantities, individualstend to know only a fraction of the world distribution.
    Cover page: Knowledge and use of price distributions by populations and individuals
    • Article
    • Peer Reviewed
    Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 37 (2015)
    What hierarchical structures do people use to encode visual displays? We examined visual working memory’s priors for locations by asking participants to recall the locations of objects in an iterated learning task. We designed a nonparametric clustering algorithm that infers the clustering structure of objects and encodes individual items within this structure. Over many iterations, participants recalled objects with more similar displacement errors, especially for objects our clustering algorithm grouped together, suggesting that subjects grouped objects in memory. Additionally, participants increasingly remembered objects as lines with similar orientations and lengths, consistent with the Gestalt grouping principles of continuity and similarity. Furthermore, the increasing tendency of participants to remember objects as components of hierarchically organized lines rather than individual objects or clusters suggests that these priors aid the perception of higher-level structures from ensemble statistics
      Cover page: Structured priors in visual working memory revealed through iterated learning
      • Thesis
      • Peer Reviewed
      UC San Diego Electronic Theses and Dissertations (2017)

      Visual working memory possesses a limited capacity for information but people can use objects’ statistical structure to help remember their features. If you know that your papers are scattered around your desk, for example, this constrains their possible locations (e.g. it is unlikely they are in the bathroom) and can help you remember specifically where each paper is on your desk. However, it is often uncertain what information visual working memory should summarize to aid recall later on. Is it sufficient to remember that the papers were near the desk? Or will you need to know where they were relative to each other? My dissertation investigates what statistical structure visual working memory seeks to encode by (Chapter 1) revealing what visuospatial groupings people expect and tend to use, (Chapter 2) examining how people use those expectations to form structured memories of objects’ groupings and (Chapter 3) evaluating the cost of using this grouping structure—what information is lost by encoding objects as components of groups. Overall, my dissertation reveals reveals that while exploiting the statistics of scenes introduces structured biases into memories, doing so enables visual memory to build accurate, multi-level representations of scenes.

        Cover page: Representations of Hierarchical Structure in Visual Memory
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2016)
        What happens to memories as we forget? They might gradually lose fidelity, lose their associations (and thus be retrieved in response to the incorrect cues), or be completely lost. Typical long-term memory studies assess memory as a binary outcome (correct/incorrect), and cannot distinguish these different kinds of forgetting. Here we assess long-term memory for scalar information, thus allowing us to quantify how different sources of error diminish as we learn, and accumulate as we forget. We trained subjects on visual and verbal continuous quantities (the locations of objects and the distances between major cities, respectively), tested subjects after extended delays, and estimated whether recall errors arose due to imprecise estimates, misassociations, or complete forgetting. Although subjects quickly formed precise memories and retained them for a long time, they were slow to learn correct associations and quick to forget them. These results suggest that long-term recall is especially limited in its ability to form and retain associations.
          Cover page: Fragile Associations Coexist With Robust Memories for Precise Details in Long-Term Memory
          Top