About

Dr. Khena Marie Iyer Swallow is an associate professor of psychology at Cornell University. She earned her Ph.D. from Washington University in St. Louis. Her research employs behavioral, neuroimaging, and eye-tracking methods to investigate how changes in events structure memory and influence ongoing cognitive and perceptual processes. Through these approaches, she examines the dynamic interactions between event perception and memory formation, contributing to a deeper understanding of how the brain organizes and processes information over time.

Research topics

• Psychology
• Artificial Intelligence
• Computer Science
• Neuroscience
• Cognitive psychology
• Social psychology
• Developmental psychology
• Medicine

Selected publications

• Attention modulates EEG spectral activity across serial positions

  bioRxiv (Cold Spring Harbor Laboratory) · 2026-01-02

  articleOpen accessSenior author

  Abstract Electroencephalographic (EEG) activity has been associated with attentional processes such as task-irrelevant stimulus suppression and orienting. The aim of this study was to understand how spectral activity evolves as words are presented in a word list learning task and as multiple components of attention are engaged under multitasking demands. We recorded scalp EEG in a delayed free-recall task in which participants encoded common noun word lists either under full attention (encoding only) or divided attention (simultaneous target detection task). In the target detection task, participants pressed a response button when a word was paired with a target-colored square but not for words paired with a distractor-colored square (cue condition). Activity in the high gamma frequencies (50-100 Hz) decreased while alpha activity (8-12 Hz) increased throughout word list presentation (i.e., across serial positions), consistent with prior work demonstrating effects of cognitive load on EEG spectral power. Divided attention attenuated this change in gamma power across the list. Cue condition modulated alpha activity evenly across serial positions, with consistently lower power during target trials than distractor trials. Our findings suggest that frequency-specific characteristics of processing during list encoding may reflect multiple components of attention that vary over different time scales. Gamma frequencies capture the interactive effects of cognitive load and dual-task demands, while alpha power separately reflects gradual increases in cognitive load and momentary orienting.

  PublisherOA PDFDOI

• Age-related differences in locus coeruleus intensity across a demographically diverse sample

  Neurobiology of Aging · 2025-03-13 · 9 citations

  article
  PublisherDOI

• Target Detection Modulates Electroencephalographic Spectral Correlates of Memory Encoding

  Journal of Cognitive Neuroscience · 2025-01-01 · 2 citations

  articleSenior author

  The current study investigates whether changes in scalp electroencephalographic activity over time reflect the effects of target detection and divided attention on memory encoding. We recorded electroencephalographic activity in 61 young adults as they memorized lists of words either under full attention (single-task) or while performing a secondary task (dual task). In both cases, colored squares appeared with each word. However, in the dual-task condition, participants also pressed a button when the colored squares were in a predefined color (target) but made no response when the squares were in a different color (distractor). Subsequent memory effects in the alpha (8-12 Hz) and high gamma (50-100 Hz) frequency bands changed throughout the trial, and these effects differed across conditions. Before word presentation, high gamma activity was associated with encoding success in the target and single-task conditions, but not in the distractor conditions. In contrast, alpha band activity decreased following word presentation, and these decreases were greater for successfully encoded words in the target condition than in the distractor or single-task conditions. The results are consistent with the view that alpha and gamma activity reflect distinct neural processes, which both contribute to memory formation, but are differentially sensitive to task demands and momentary shifts in attention.

  PublisherDOI

• The role of emotional content in segmenting naturalistic videos into events.

  Journal of Experimental Psychology General · 2025-05-27 · 1 citations

  articleSenior author

  (moments that separate two events) of different grains (Experiment 1: neutral grain; Experiment 2: fine grain or coarse grain). We found that participants agreed with each other about when emotion changes occurred in the videos, demonstrating that viewers are able to track changes in the emotional content of dynamic naturalistic videos as they are experienced. Moreover, the emotion changes participants identified were temporally aligned with the event boundaries identified by other groups. In addition, valence and arousal changes rated by a separate group of participants uniquely predicted the likelihood of identifying emotion changes and event boundaries, even after accounting for other types of change. However, emotion changes were more strongly tied to valence changes than arousal changes while coarse boundaries were more strongly associated with affective changes than were fine boundaries. These novel findings suggest that emotional information plays a substantial role in structuring ongoing experiences into meaningful events, providing a stronger basis for understanding how emotion shapes the perception and memory of everyday experiences. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

  PublisherDOI

• Blood oxygenation level-dependent responses in neuromodulatory nuclei and their associations with attention and memory across age groups

  Neurobiology of Aging · 2025-07-16 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• Attention-dependent coupling with forebrain and brainstem neuromodulatory nuclei differs across the lifespan

  GeroScience · 2025-03-04 · 3 citations

  articleOpen access

  Attentional states reflect the changing behavioral relevance of stimuli in one's environment, having important consequences for learning and memory. Supporting well-established cortical contributions, attentional states are hypothesized to originate from subcortical neuromodulatory nuclei, such as the basal forebrain (BF) and locus coeruleus (LC), which are among the first to change with aging. Here, we characterized the interplay between BF and LC neuromodulatory nuclei and their relation to two common afferent cortical targets important for attention and memory, the posterior cingulate cortex and hippocampus, across the adult lifespan. Using an auditory target discrimination task during functional MRI, we examined the influence of attentional and behavioral salience on task-dependent functional connectivity in younger (19-45 years) and older adults (66-86 years). In younger adults, BF functional connectivity was largely driven by target processing, while LC connectivity was associated with distractor processing. These patterns are reversed in older adults. This age-dependent connectivity pattern generalized to the nucleus basalis of Meynert and medial septal subnuclei. Preliminary data from middle-aged adults indicates a transitional stage in BF and LC functional connectivity. Overall, these results reveal distinct roles of subcortical neuromodulatory systems in attentional salience related to behavioral relevance and their potential reversed roles with aging, consistent with managing increased salience of behaviorally irrelevant distraction in older adults. Such prominent differences in functional coupling across the lifespan from these subcortical neuromodulatory nuclei suggests they may be drivers of widespread cortical changes in neurocognitive aging, and middle age as an opportune time for intervention.

  PublisherOA PDFDOI

• The role of emotional content in segmenting naturalistic videos into events

  2025-03-26

  preprintOpen accessSenior author

  The human mind automatically divides continuous experience into meaningful events (event segmentation). Despite abundant evidence that some kinds of situation changes (e.g., action, goal, or location changes) contribute to event segmentation, a component of experience that is critical for understanding and predicting others’ behavior, emotion, is rarely investigated. In two experiments, we sought to establish that viewers can track emotion changes while viewing naturalistic videos, and that these changes contribute to event segmentation. Participants watched commercial film excerpts while identifying either emotion changes or event boundaries (moments that separate two events) of different grains (Experiment 1: neutral-grain; Experiment 2: fine-grain or coarse-grain). We found that participants agreed with each other about when emotion changes occurred in the videos, demonstrating that viewers are able to track changes in the emotional content of dynamic naturalistic videos as they are experienced. Moreover, the emotion changes participants identified were temporally aligned with the event boundaries identified by other groups. In addition, valence and arousal ratings from separate groups of participants uniquely predicted the likelihood of identifying emotion changes and event boundaries, even after accounting for other types of change. However, emotion changes were more strongly tied to valence changes than arousal changes while coarse boundaries were more strongly associated with affective changes than were fine boundaries. These novel findings suggest that emotional information plays a substantial role in structuring ongoing experiences into meaningful events, providing a stronger basis for understanding how emotion shapes the perception and memory of everyday experiences.

  PublisherOA PDFDOI

• People can reliably detect action changes and goal changes during naturalistic perception

  Memory & Cognition · 2024-02-05 · 9 citations

  articleOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

• Event segmentation and encoding rely on information accumulated over different temporal scales

  2024-03-29 · 2 citations

  preprintOpen accessSenior author

  People spontaneously divide experience into discrete units (event segmentation) that shape episodic memory. Prominent accounts of segmentation suggest that it reflects mechanisms that update mental representations of the ongoing situation (event models) by integrating prior knowledge (e.g., schemata) with information about the current state of the world. How much external information needs to be accumulated to build a stable event model and guide segmentation is still unclear. We examined this question by asking participants to segment and afterwards recall video excerpts from commercial films that were manipulated to limit the continuous and coherent accumulation of information from the videos: Videos were presented either uninterrupted, interrupted by a white-noise display, or interrupted with additional jumbling of the interrupted video clips. Interrupting or jumbling videos every 1-minute (Experiment 1) did not significantly change overall segmentation rates, patterns, or the tendency to hierarchically organize events. However, a finer-grained temporal analysis indicated that the segmentation rate briefly increased following a jumbled clip, stabilizing after 5s. When the videos were interrupted or jumbled more frequently (every 5s; Experiment 2), however, segmentation patterns changed to reflect the transient signals created by clip onsets rather than video content. These findings suggest that information accumulated over windows longer than 5 s, but shorter than 10 s, is sufficient for building event models that can support content-based segmentation. In contrast, although jumbling the videos every minute (Experiment 1) minimally impacted segmentation patterns, it significantly reduced the number of events recalled and their organization with respect to time and semantics. Thus, event segmentation and memory encoding rely on information accumulated over different timescales.

  PublisherOA PDFDOI

• The role of emotional content in segmenting naturalistic videos into events

  2024-05-28 · 2 citations

  preprintOpen accessSenior author

  The human mind automatically divides continuous experience into meaningful events (event segmentation). Despite abundant evidence that some kinds of situation changes (e.g., action, goal, or location changes) contribute to event segmentation, a component of experience that is critical for understanding and predicting others’ behavior, emotion, is rarely investigated. In two experiments, we sought to establish that viewers can track emotion changes while viewing naturalistic videos, and that these changes contribute to event segmentation. Participants watched commercial film excerpts while identifying either emotion changes or event boundaries (moments that separate two events) of different grains (Experiment 1: neutral-grain; Experiment 2: fine-grain or coarse-grain). We found that participants agreed with each other about when emotion changes occurred in the videos, demonstrating that viewers are able to track changes in the emotional content of dynamic naturalistic videos as they are experienced. Moreover, the emotion changes participants identified were temporally aligned with the event boundaries identified by other groups. In addition, valence and arousal ratings from separate groups of participants uniquely predicted the likelihood of identifying emotion changes and event boundaries, even after accounting for other types of change. However, emotion changes were more strongly tied to valence changes than arousal changes while coarse boundaries were more strongly associated with affective changes than were fine boundaries. These novel findings suggest that emotional information plays a substantial role in structuring ongoing experiences into meaningful events, providing a stronger basis for understanding how emotion shapes the perception and memory of everyday experiences.

  PublisherDOI

Frequent coauthors

• Yuhong Jiang

  China University of Geosciences

  29 shared

• Jeffrey M. Zacks

  Washington University in St. Louis

  16 shared

• Adam K. Anderson

  Cornell University

  11 shared

• Hamid B. Turker

  Cornell University

  10 shared

• Eve De Rosa

  Cornell University

  10 shared

• Wen‐Ming Luh

  8 shared

• Adam W. Broitman

  University of Pennsylvania

  8 shared

• Tal Makovski

  7 shared

Labs

• AMP LabPI