Biology subjects

Huffman, D. J.

Publications and source records attributed to Huffman, D. J..

5 recordsLinked to original sources

bioRxiv2026

Snap Back to Reality: The Comparison of Spatial Memory in the Lab and the Real World

We thank the Department of Psychology at Colby College for supporting this work. Derek J. Huffman played a primary role in conceptualization, funding acquisition, project administration, methodology, resources, supervision, writing-initial draft, and writing-review and editing; and a supporting role in formal analysis, software, validation, and visualization. Paisley J. Annes played a lead role in validation and visualization; and a supporting role in conceptualization, data curation, formal analysis, methodology, software, writing-initial draft, and writing-review and editing. Chandrachud Gowda played a primary role in Investigation; and a supporting role in conceptualization, data curation, formal analysis, methodology, project administration, visualization, and software. Lior Colina played a supporting role in conceptualization, methodology, and software. Memory is most commonly studied using lab-based measures; however, spatial memory for large-scale environments, such as cities, typically takes extended time and motivation to learn, thus raising questions about the ecological validity of findings from traditional lab-based paradigms (e.g., information that is learned over a short timescale and with no real-world relevance). We leveraged technological breakthroughs to create a custom smartphone application to compare situated spatial memory with lab-based measures. Specifically, we compared performance in healthy young adults across two established lab-based tasks, judgments of relative direction (JRD) and map drawing, and our novel app-based, in situ pointing task for the same familiar, large-scale, real-world environment (the participants college campus). We observed a strong correlation between JRD performance and map-drawing performance. App-based pointing showed lower error and reduced inter-individual variability relative to JRD performance, but weak correlations with lab-based measures. We also developed a novel analytical technique in which we transformed the app-based pointing into a relational, JRD-like metric, and we observed strong correlations with the lab-based tasks. Moreover, we observed correlated patterns of errors across all tasks, thus suggesting that these tasks tap into partially overlapping cognitive representations. Our results provide a pivotal advancement to our understanding of both shared and unique variance across spatial memory paradigms and support the use and further development of mobile navigation tools as complements to lab-based assessments for studying spatial cognition and differences across populations, including patients with Alzheimers disease who often report getting disoriented even within familiar spatial environments.

animal behavior and cognition↗

bioRxiv2026

Living off the grid: Spatial representations show systematic non-Euclidean distortions regardless of their age and how measured

Spatial memory is invaluable for most mobile organisms, yet nature of the underlying representations that we employ for spatial memory has been fiercely contested. On the one hand, the presence of place cells in the hippocampus and grid cells in the medial entorhinal cortex appear to support the argument spatial representations may follow Euclidean axioms, termed "the cognitive map hypothesis." On the other hand, decades of behavioral research in humans reveals that spatial memory often shows characteristic distortions, leading to the alternative, cognitive graph hypothesis, to account for this aspect of spatial memory. Importantly, the majority of laboratory studies tend to occur within novel environments in which participants often have only limited exposure and no personal relevance. We were interested in studying large-scale memory across multiple time scales: from a virtual environment (e.g., learned over several minutes) to a college campus (e.g., months to a few years) to a hometown environment (e.g., many years). Across several tasks, we found that participants exhibited systematic distortions in their memory for all of these environments. Likewise, we found significant correlations between performance on several spatial memory tasks (both between participants and within-participant analyses of patterns of errors), thus suggesting that these tasks tap into partially overlapping cognitive representations and supporting their construct validity. Altogether, our findings provide clear evidence for cognitive graph hypothesis and support the construct validity of several spatial memory tasks within large-scale, real-world environments that are learned over the course of several months to years. Public Significance StatementSpatial memory is key for our ability to live independent lives (e.g., patients with Alzheimers disease lose independence, partially due to disorientation in familiar environments). Typical laboratory-based measures of spatial memory use novel environments that may differ in complexity vs. real-world environments (e.g., size, layout, number of landmarks, duration of exploration, personal relevance). We leveraged breakthroughs in technology to study spatial memory across several tasks and temporal scales, from a novel environment navigated over the course of several minutes to a university campus (e.g., months to years) to hometowns (e.g., years to decades). We observed consistent evidence for systematic distortions in spatial memory, which supports the hypothesis that spatial memory is supported by a cognitive graph, thus posing an important challenge to the extremely influential Euclidean, "cognitive map" hypothesis that was awarded a Nobel Prize in 2014.

animal behavior and cognition↗

bioRxiv2026

Repetition strengthens memory: Evidence from human behavioral data and global matching models

Computational models and neurobehavioral data suggest that encoding variability affects forced-choice mnemonic discrimination. Here, we experimentally manipulated encoding variability on the forced-choice Mnemonic Similarity Task by varying stimulus repetitions during encoding. We first generated predictions from a global matching model. Behavioral data supported all predictions. Across most conditions, repetitions consistently enhanced mnemonic discrimination; however, when encoding variability was induced by 3-repetitions of the original version of the non-corresponding lure and 1-repetition of the target during learning, individuals exhibited increased interference. These findings provide further insight into theories of human memory, especially the effect of stimulus repetition on mnemonic discrimination.

animal behavior and cognition↗

bioRxiv2023

Computational models suggest that human memory judgments exhibit interference due to the use of distributed representations

Episodic memory is a core function that allows us to remember the events of our lives. Given that many events in our life contain overlapping elements (e.g., similar people and places), it is critical to understand how well we can remember the specific events of our lives vs. how susceptible we are to interference between similar memories. Several prominent theories converged on the notion that pattern separation in the hippocampus causes it to play a greater role in processes such as recollection, associative memory, and memory for specific details, while distributed representations in the neocortex cause it to play a stronger role in domain-specific memory. We propose that studying memory performance on tasks with targets and similar lures provides a critical testbed for comparing the extent to which human memory is driven by hippocampal pattern separation vs. more distributed representations (e.g., neocortex) vs. a blend thereof. We generated predictions from several computational models and then tested these predictions in a large sample of human participants. We found a linear relationship between memory performance and target-lure pattern similarity within a neural network simulation of area IT, an object-processing region of the brain. We also observed strong effects of test format on performance and consistent relationships between test formats. Altogether, our results were better accounted for by distributed memory models than the pattern-separated representations of the hippocampus; therefore, our results provide important insight into prominent memory theories by suggesting that memory performance is primarily driven by distributed representations (e.g., neocortex).

neuroscience↗

bioRxiv2018

Which way is the bookstore? A closer look at the judgments of relative directions task.

We present a detailed analysis of a widely used assay in human spatial cognition, the judgments of relative direction (JRD) task. We conducted three experiments involving virtual navigation interspersed with the JRD task, and included confidence judgments and map drawing as additional metrics. We also present a technique for assessing the similarity of the cognitive representations underlying performance on the JRD and map drawing tasks. Our results support the construct validity of the JRD task and its connection to allocentric representation. Additionally, we found that chance performance on the JRD task depends on the distribution of the angles of participants responses, rather than being constant and 90 degrees. Accordingly, we present a method for better determining chance performance.

animal behavior and cognition↗