Giovanna C. Del Sordo

Research Interests

My research involves the study of human cognitive processes, with the main objective of understanding how it relates to LC-NE (locus-coeruleus norepinephrine) system functioning. My current research focuses on three aspects of human attention: (1) neural gain fluctuations during attentional tasks; (2) differentiating between different forms of sustained attention; and (3) individual differences in cognitive abilities as a predictor of attentional performance. 

For my PhD dissertation, I investigated ways to distinguish between active and passive forms of sustained attention using the classic Multiple Object Tracking paradigm (see below for a poster presented at Psychonomics 2024). 

Another area of interest I have is on the exploration-exploitation tradeoff, the cognitive balance between exploring novel options and exploiting known strategies to optimize decision-making. The LC-NE system has been linked to this tradeoff, and its activity can be monitored through pupillometry (an non-invasive method of measuring pupil dilation). The LC-NE is tightly linked to attentional states and behavioral states and I hope that my research can advance our understanding of LC functioning. 

Similarly, I am also interested in attentional performance, and more specifically, on the interaction between attentional performance and effort mobilization  (a.k.a. cognitive effort).  I am looking at how aware people are about their own attentional processes (meta-attention) while performing a sustained attention task, and how their confidence judgements correlate with their perceived cognitive effort. 

Apart from my own research, I'm also actively involved in collaborative efforts with researchers across different areas, where I contribute to methodological plans and take the lead on statistical analyses.

Some of my research projects

Exploration vs. exploitation in a novel complex card sorting task: Insight from pupillometry.

The exploration-exploitation tradeoff is a key element of Adaptive Gain Theory, suggested to promote the optimization of behavior toward high performance. This tradeoff is closely related to the phasic and tonic modes of the locus coeruleus-norepinephrine (LC-NE)  system.

To measure exploration and exploitation using a paradigm with tonic (baseline pupil size) and phasic (task-evoked pupil response) recordings, the present study used a novel Complex Card Matching Task (CCMT).

In this task, participants classify cards according to different, unspecified rules, Participants learn complex classification rules through trial and error using correct-incorrect feedback. This task taps into cognitive flexibility, as participants switch between exploration trials (i.e., testing new rules) and exploitation trials (exploiting the rule that currently applies). Two versions of this task were created to manipulate task difficulty. The “easy” version of the task has rules made up of three possible characteristics: color, shape, and number of shapes. Participants must classify cards according to six possible rules defined by consistencies across one or two features. In the “difficult” version, we added another characteristic (size of the shapes). In addition to the six rules in the easy version, this adds four more classification possibilities.

Our findings showed that exploration was associated with larger pupil size than exploitation, suggesting heightened LC-NE activity during uncertain decision-making. This effect was observed in both pretrial and task-evoked pupil responses, although task difficulty moderated these relationships. Pretrial pupil size remained consistent across difficulty levels, whereas task-evoked responses varied with difficulty, with higher task difficulty leading to greater pupil dilation in both exploration and exploitation. The pupil dynamics observed in the exploration-exploitation tradeoff highlight the complexity of this process, indicating that it cannot be fully explained by a single theoretical framework. 

The CCMT is available for research use on GitHub (both a behavioral and pupillometry versions): https://github.com/giovannacdelsordo/Complex-Card-Matching-Task.git 

Preliminary results were presented at the Psychonomic Society's 64th Annual Meeting (November 16-19, 2023) in San Francisco, CA, USA. And a manuscript is under review! 

Differentiating between active and passive visual sustained attention

My dissertation work investigated the possible distinction between two subtypes of sustained attention: (1) active sustained attention, which demands continuous cognitive engagement, and (2) passive sustained attention, characterized by vigilance and readiness for rare events. 

My rationale was that even though the terms "sustained attention" and "vigilance" are interchangeably used in the literature to mean sustained attention, they do not have the same exact definitions. Therefore, I postulated that vigilant attention should be seen as a subtype of sustained attention. The experiments conducted aimed to differentiate these two forms of attention. Active sustained attention was assessed using a traditional Multiple Object Tracking task (renamed Active-MOT), while a modified version of this task was developed to measure passive sustained attention (Passive-MOT). 

My dissertation is available on ProQuest here. 

The results were presented at the Psychonomic Society's 65th Annual Meeting (November 21-24, 2024) in New York, NY, USA.

Individual differences in attentional resource allocation. 

One of my ongoing project is to look at the contribution of cognitive reserve (CR) and fluid intelligence (gF) separately and conjointly on individual differences observed in attentional performance. Strong individual differences in attentional resource allocation have been evidenced depending on individuals’ gF, working memory capacity, and executive functioning. In the present study, we proposed to examine CR as a more comprehensive factor possibly contributing to these individual differences. CR is a latent construct referring to the capacity of individuals to efficiently use cognitive resources and adapt to challenges. It is believed to build up throughout the lifespan through life experiences (education, occupation, leisure time activities...). 

Preliminary results were presented at the 2023 Rocky Mountain Psychological Association conference in Albuquerque, NM.  Data collection is still ongoing, stay tuned!