Imagine you are walking from a coffee shop to your college classroom when you experience a shocking event: witnessing an individual fall off their bike and onto the sidewalk. When you remember how much time had passed between the coffee shop and the college campus, would you think that these events occurred closer in time? Or farther? Would the shock from the bike crash scare you into remembering that the coffee shop study session occurred before or after the college class?
Research from various pioneers in the cognitive neuroscience field has tried to study how our temporal memory (the memory for time-related components of an event) is influenced by these salient or emotional events (Aston-Jones & Cohen, 2005; Clewett et al., 2020, 2025; DuBrow et al., 2017; DuBrow & Davachi, 2013, 2014; Ezzyat & Davachi, 2011, 2014; Faber & Gennari, 2015, 2017; Rouhani et al., 2024). While including previous works in my research, I hypothesize that we can actually impair our memory of events through altering our perception of time between them.
Memory research often uses the same terminology to refer to the “clips” or “episodes” that make up our memories, events. In the prior example of walking from the coffee shop to the college campus, we have three events: the coffee shop study session, the walk between the two locations, and the college class. Each event has its own context, which comprises the place, sights, sounds, and mental state that you are in. Studies have shown that subjective time duration (“how much time do I think this event took?”) increases as there are differences perceptually within the same context (Faber & Gennari, 2015, 2017). The experience of walking on campus between the coffee shop and the classroom will be remembered as having occurred longer than what objectively took place because of the different sights you saw. On the other hand, sitting in the classroom for hours at a time will feel subjectively shorter afterwards because you are not experiencing as many perceptual differences.
Given this early finding, it is intuitive that memory for events are often remembered better temporally when items are within the same context, or having little perceptual changes within-context. These aspects of temporal memory have been seen to be associated with the hippocampus and, in a broader sense, the medial temporal lobe (Dubrow & Davachi, 2013, 2014; Ezzyat & Davachi, 2011, 2014), which are locations of the brain best understood to contribute to embedding our experiences into cohesive and understandable memories.
But how does this change in perception affect our temporal memory? This finding of subjective time being altered has also been seen with pupillometry measures (pupil dilation; Clewett et al., 2020, 2025), showcasing that locus coeruleus activity and norepinephrine release modulate this experience (for more information, refer to my other article here). However, the findings are counterintuitive: more norepinephrine release (“fight or flight” chemical of the brain) leads to longer perceptions of time as well as reversed order of events occurring. But I thought from prior research that having rewarding or salient events also creates more variable contexts, such as diversifying one’s mental or emotional state, therefore thought to maximize memory for events (DuBrow et al., 2017; Rouhani et al., 2024)?
A common misconception about neuroscience and psychology research is that we need to look at nonlinear relationships between our measures. A common framework in the field of research studying norepinephrine is one by Aston-Jones & Cohen (2005), which claims that norepinephrine release and cognitive performance is actually an “inverted-U” shape. In other words, we need to find the sweet spot where we do not have too little norepinephrine (inattentive) and not too much (distractible) to be task-engaged and perfectly attentive to our experiences.
The overall arching question is: how is our perception of time influencing our memory of events? Depending on how exciting or surprising your daily life is, you might feel as though more time has occurred and therefore have trouble remembering the order or accuracy of events. However, you do not want to stay stuck in the same location for too long, as you become inattentive to what is going on around you and this leads to confusion. Future research needs to be conducted on how we get to this optimal stimulating experience in our daily lives without overwhelming our brains with too much information. Through my future research and onward, I aim to answer this gap in the literature.
References.
Aston-Jones, G., & Cohen, J. D. (2005). AN INTEGRATIVE THEORY OF LOCUS COERULEUS-NOREPINEPHRINE FUNCTION: Adaptive Gain and Optimal Performance. Annual Review of Neuroscience, 28(1), 403–450. https://doi.org/10.1146/annurev.neuro.28.061604.135709
Clewett, D., Gasser, C., & Davachi, L. (2020). Pupil-linked arousal signals track the temporal organization of events in memory. Nature Communications, 11(1), 4007. https://doi.org/10.1038/s41467-020-17851-9
Clewett, D., Huang, R., & Davachi, L. (2025). Locus coeruleus activation “resets” hippocampal event representations and separates adjacent memories. Neuron, 113(15), 2521-2535.e8. https://doi.org/10.1016/j.neuron.2025.05.013
DuBrow, S., & Davachi, L. (2013). The influence of context boundaries on memory for the sequential order of events. Journal of Experimental Psychology: General, 142(4), 1277–1286. https://doi.org/10.1037/a0034024
DuBrow, S., & Davachi, L. (2014). Temporal memory is shaped by encoding stability and intervening item reactivation. The Journal of Neuroscience: The Official Journal of the Society for Neuroscience, 34(42), 13998–14005. https://doi.org/10.1523/JNEUROSCI.2535-14.2014
DuBrow, S., Rouhani, N., Niv, Y., & Norman, K. A. (2017). Does mental context drift or shift? Current Opinion in Behavioral Sciences, 17, 141–146. https://doi.org/10.1016/j.cobeha.2017.08.003
Ezzyat, Y., & Davachi, L. (2011). What constitutes an episode in episodic memory? Psychological Science, 22(2), 243–252. https://doi.org/10.1177/0956797610393742
Ezzyat, Y., & Davachi, L. (2014). Similarity breeds proximity: Pattern similarity within and across contexts is related to later mnemonic judgments of temporal proximity. Neuron, 81(5), 1179–1189. https://doi.org/10.1016/j.neuron.2014.01.042
Faber, M., & Gennari, S. P. (2015). In search of lost time: Reconstructing the unfolding of events from memory. Cognition, 143, 193–202. https://doi.org/10.1016/j.cognition.2015.06.014
Faber, M., & Gennari, S. P. (2017). Effects of learned episodic event structure on prospective duration judgments. Journal of Experimental Psychology: Learning, Memory, and Cognition, 43(8), 1203–1214. https://doi.org/10.1037/xlm0000378
Rouhani, N., Clewett, D., & Antony, J. W. (2024). Building and Breaking the Chain: A Model of Reward Prediction Error Integration and Segmentation of Memory. Journal of Cognitive Neuroscience, 36(11), 2401–2414. https://doi.org/10.1162/jocn_a_02215