Here you will find brief descriptions of some of my published work, as well as descriptions of some ongoing projects with which I am involved.

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Figure from Papesh et al. (in pess). 4 pairs of faces and mock IDs are shown.
From Papesh et al. (in press). Results showing that when matches or mismatches are rare, they are often undetected.
From Papesh et al. (in press). Results showing that when misatches are rare, observes quicky develop a bias to call identitis "matches."

Papesh, M. H., Heisick, L. L., & Warner, K. A. (2018). The persistent low-prevalence effect in unfamiliar face-matching: The roles of feedback and criterion shifting. Journal of Experimental Psychology. Applied.

A major theme in my recent research has been the difficulties of unfamiliar face perception. Although we like to think of ourselves as face experts, matching an unfamiliar face to a photograph is a difficult and error-prone task, even under the best of circumstances. This poses a potentially huge problem, as many applied scenarios rely on observers' ability to accurately verify government-issue ID documents. For example, any time you visit the airport, try to pass border control, or simply try to buy age-restricted goods, you are often handing over your license or passport for someone to scrutinize... hopefully accurately. Unfortunately, matching identities is tough and errors are common.


Further complicating matters is the fact that observers rarely encounter fake or stolen IDs. Rarely occurring mismatching identities often go undetected (Papesh & Goldinger, 2014), so we sought to investigate whether observers could be "retrained" to avoid what would represent costly or dangerous errors in the real world. Across five experiments, we found that observers were strongly biased to call pairs of identities "matches" in the face of rarely occurring mismatches, and that neither feedback nor perceptual experience with a greater number of mismatching identities was sufficient to improve performance. While this doesn't bode well for our ability to catch someone using a fake ID, we are still working on figuring out how to improve our odds!

Middle: Results showing that when matches or mismatches are rare, they are often undetected.

Bottom: Results showing that when mismatches are rare, observers quickly develop a bias to call identities "matches."


Sample mock missing person post from Heisick & Hicks (under review).
Figure from Heisck & Hicks (under review) showing that attentinal cost is only incurred for faces when they are associated with an intention.

Heisick, L.L., & Hicks, J.L. (Revisions in progress). Missing sightings of missing persons: Prospective person memory and other-race effects.


You would be hard-pressed to find someone who didn't agree that locating missing individuals is an important task. The process of viewing a missing person poster, recognizing and identifying a missing person, and subsequently remembering to alert the authorities, is considered a variant of prospective memory, remembering to carry out an action in the future. Person prospective memory (PPM) tasks are, unfortunately, much more error-prone than traditional prospective memory work. Because there are numerous pitfalls to unfamiliar face recognition (e.g., other-race effects), I was interested in how these contribute to (or further impair) PPM performance. Participants studied mock missing person photos (shown top left) and were instructed to "alert the authorities" during their task if encountered. Importantly, the race of the missing person was the same as or different from observers. 

Results showed robust other-race effects: Caucasian participants trying to locate missing people of another race were significantly less accurate in both prospective accuracy and retrospective face identification. In addition, maintaining faces as prospective memory targets was associated with an attentional cost (shown middle left), relative to maintaining faces for subsequent identification only (shown bottom left). These data suggest PPM may be difficult, attentionally-demanding, and possibly inefficient... which doesn't bode well for locating missing people.


Mock passports and data from Heisick et al. showing that social categorization improves unfamiliar face-matching accurcy, but may be associated with a bias to call pairs of faces "match."

Heisick, L.L., Guevara-Pinto, J.D., Papesh, M.H. (in preparation). Implicit versus Explicit Social Categorization in Unfamiliar Face Perception.

It is possible to belong to many different socially-constructed categories. For example, you may consider yourself a sports fan, pet owner, or cheese plate enthusiast, and research shows the act of categorizing someone as a member of your social "in-group" influences unfamiliar face recognition. Specifically, learning faces classified as in-group members improves subsequent recognition (Bernsetin et al., 2007). To extend this research, I have conducted two experiments in which United States-based participants made recognition or face-matching decisions about faces embedded into mock passports. Mock passports were chosen to represent "in-group" and "out-group" membership by selecting countries that U.S. participants would consider generally friendly, or generally unfriendly, in foreign relations.

To the middle left are results from our investigation of face-matching, where observers had to decide whether two faces, one large and the other embedded into a fake passport, showed the same person or two different people. This graph shows the signal detection index of d' (sensitivity) as a function of whether faces were in-group or out-group, and whether participants explicitly identified the country of origin or only made matching decisions (implicit). This pattern suggests that social categorization may be relatively automatic and also benefit face-matching performance, supporting social-cognitive models of face perception (Hugenberg et al., 2010). However, a brief caveat: In-group categorization was also associated with a bias to call identities "matches," shown bottom left, suggesting we may be more likely to tolerate variability within our in-group, sometimes in error. This project is currently being prepared for submission.


Sample trial of item-method directed forgetting, with observers told to remember or forget individal items. Below is a graph of the directed forgetting effect, with items associated with forget instructions remembered less often than items associated with remember instructions.

Although most memory research focuses on successful remembering, I am particularly interested in what happens when we forget. Forgetting is often described as a failure of memory, but intentionally forgetting irrelevant, distracting, or wrong information benefits memory (see MacLeod, 1998). For example, when changing your email password, it is critical to be able to intentionally forget your previous password to minimize confusion (and irritation) when trying to access the account again later. 


I am working on several experiments examining whether forgetting on purpose results in active inhibition or withdrawal of attention (Taylor, 2005; Taylor & Fawcett, 2011). I most often use item-method directed forgetting paradigms (shown top right) to investigate this question, wherein participants are told to remember or forget stimuli on an item-by-item basis. Across both behavioral and eye-tracked experiments, I am interested in determining how attention might be inhibited from to-be-forgotten information, potentially resulting in a memory trace that is weak or degraded and thus less likely to influence subsequent cognition. I am also examining how greater effort to remove or inhibit to-be-forgotten information might be reflected in pupil dilation, and if greater effort predicts more effective forgetting. To investigate whether contextual or identity information is inhibited during intentional forgetting, some of my current experiments use images of everyday objects (examples shown to the right) and a comparison of performance across both explicit and implicit memory tests to uncover what happens to a memory after it has been inhibited.

My dissertation also focuses on memory failure, combining my interests in forgetting and face perception. A large body of evidence suggests that forgetting can sometimes happen as a consequence of remembering, and we may be more likely to forget information if it is represented very strongly in memory. I am very excited to expand my research into retrieval-induced forgetting, and I look forward to having preliminary results to report soon!


Sample trial of faces surrouned by borders indicating high reward or low reward. Bottom panel shows sample pupil dilation data, with a larger pupil response for hits than correct rejections.

Part of my investigation into memory and reward stems from an empirical inconsistency in what pupil dilation indexes about cognitive processing. While it is well-known that the pupils dilate in response to changes in ambient lighting or in emotional arousal, pupil dilation is also a useful index of cognitive effort. Greater pupil dilation is often associated with greater effort; however, some research has shown that strong memories, which should be quickly and easily retrieved, are also associated with larger pupils.


To address this question, I have ongoing investigations examining pupil dilation when participants are engaged in reward processing. My goal is to examine the effects of higher reward on pupil dilation, to compare pupil dilation and memory performance when participants must exhibit greater effort at encoding, which should result in a stronger memory, with greater effort at retrieval, which should reflect a more effortful memory search. With funding I received from the LSU Department of Psychology, I was able to pay participants for their efforts to encourage reward processing. Participants studied faces associated with high or low reward values (examples shown top left), and some were informed of rewards at encoding, and others at retrieval. All data are collected for this project, and I am in the process of analyzing it.  

Bottom left: Data replicating the pupil old/new effect, whereby pupil dilation is larger for items that are correctly identified as old/previously studied, relative to correctly rejected new items.


Although the above represents many of my ongoing projects, I have other investigations that are not listed here that I am happy to discuss further. If you have any questions, would like more insight, or want to know about other projects I have ongoing or completed, please get in touch! 

In summary, my research interests and ongoing projects include:

  • Investigating the functional utility of eye movements across learning and retrieval.

  • Examining the interplay between memory retrieval and memory rejection, as well as failures of memory (e.g., forgetting).

  • Understanding the function of forgetting on purpose (e.g., forgetting your expired email password), as opposed to forgetting on accident (e.g., forgetting your new email password after changing it).

  • Exploring the relationship between pupil dilation and memory, including the impact of reward processing and cognitive effort.

  • Examining how we remember to carry out future tasks, particularly when those tasks involve faces (such as finding a missing person).

  • Investigations of face perception, in particular the difficulties of unfamiliar face recognition and matching, and how to improve these processes.

Books in front of a bookshelf.