Memory Binding and Forgetting in Development

• In Event: 1-163 - Memory and the Developing Brain: Sampling Behavior and Defining Constructs

Integrative Statement

In this work, we used a model-based approach to investigate developmental changes in memory retention and forgetting. In many cases, veridical memory requires binding, or closely associating, multiple aspects of an experience (e.g., where and when an event occurred). Prior work has demonstrated improvement of this ability throughout childhood (Lee et al., 2016). Other work found evidence that the ability to form complex binding structures including 3 elements was slower to develop than simpler structures including 2 elements, using a recall paradigm (Yim, Dennis, & Sloutsky, 2015). However, it is unknown whether a similar developmental progression affects binding of elements in recognition memory, which is generally considered less demanding than recall. Developmental changes in binding are important in part because developmental improvements in complex binding may result in an improved ability to resist retroactive interference (i.e., forgetting of previously learned information due to new learning; Darby & Sloutsky, 2015), although evidence for this relationship has been largely indirect. The current work aims to investigate the development of complex binding in recognition memory, and to better understand the relationship between binding and retroactive interference.

To investigate these issues we tested binding as well as retroactive interference in 5-year-olds, 8-year-olds, and adults. Participants first learned to associate objects differing by shape and color with cartoon characters (see Fig. 1A). Importantly, participants learned 2 sets of these contingencies; each set included some objects consisting of the same shapes and colors that were recombined and associated with different characters across sets (i.e. overlapping contingencies, which were expected to produce interference), and some objects with different shapes and colors between sets (i.e., control contingencies; see Fig. 1B). We measured interference by taking the difference between accuracy for the initial overlapping and control contingencies after learning the second set. Following the interference task, participants completed a novel memory binding task designed to probe what binding structures had been learned using a forced-choice recognition paradigm.

The results replicated previous findings of a developmental decrease in susceptibility to retroactive interference (see Fig. 2A). We analyzed performance on the binding task with a multinomial processing tree (MPT) model that estimated different binding structures: [experiment - shape (or color)], [shape – color], and [shape - color - character]. Using Bayesian analytic techniques, we found strong evidence of developmental differences in all three types of binding structures (see Fig. 2B). Parameters estimating simple 2-way binding (e.g., [shape - color]) showed significant differences between 5- and 8-year-olds only, whereas the complex [shape - color - character] binding showed evidence of differences between all three age groups, suggesting later development of complex binding in recognition memory, similar to recall. In addition, an individual differences analysis revealed a significant relation between complex binding and reduced interference, supporting the hypothesis that complex binding strengthens resistance to interference. Importantly, our model-based approach allowed greater insights into binding processes than could be inferred by standard statistics. This work improves our understanding of the mechanisms contributing to relational memory and forgetting, as well as how these mechanisms develop.

Authors

• Kevin Darby, University of Virginia
  Presenting Author

• Vladimir M. Sloutsky, The Ohio State University
  Non-Presenting Author