Research Projects

Decision-Making Strategy Changes in Dynamic Environments

How do people adjust their decision strategies in changing environments?
Real-world decisions rarely unfold in stable environments: goals shift, routes become blocked, and rewards change. Classic accounts distinguish between model-free strategies, which rely on cached values of past actions, and model-based strategies, which plan using an internal model of the environment. In the last decade, younger adults have also been shown to engage intermediate strategies such as Successor Representation learning. However, it remains unclear how we adapt our decision strategies as the environment changes. The current project addresses this question by examining decision-making behavior in a virtual maze. Using computational modeling, we identify which strategies underlie behavior and how their use changes over time and across environmental conditions. We examine these changes in conjunction with navigation strategy use.

This project is in collaboration with Sukran Karaosmanoglu, a post-doctoral researcher in the Informatics Department at the University of Hamburg.

Credit Assignment abilities in Aging Adults

Decision-making often involves changes in stimulus & reward contingencies (e.g. a previously unrewarded choice is now rewarded). In these cases, we have to be able to link specific choices or actions to their outcomes. This is analogous to thinking: “What choice did I make in order to get this reward?” and subsequently increasing the value of choosing that same choice option in the future. This process is referred to as credit assignment.
Accurate credit assignment depends on the representation of the task (i.e, cognitive map of the environment). Without such a representation individuals are unable to causally attribute reward feedback.
In the current project, we aim to understand if older adults, once taught the representation of the task, successfully engage in credit assignment.

This project is in collaboration with Dr. Xiangjuan Ren (University of Hamburg) and Dr. Rani Moran (Queen Mary University of London).

Older Adults Learning from Surprising Events

When we learn about a novel decision-making environment, we are sometimes presented with surprising outcomes which can be (1) outlier events and therefore uninformative or (2) indicative of a change we must adapt to. The ability to distinguish between these two types of surprising outcomes and act (or make decisions) is critical during decision-making. While younger adults seem to be quite skilled at detecting when a surprising outcome requires them to update their representation of the environment, older adults may have deficits in doing so.

The two current projects aim to investigate this how older adults learn from surprising outcomes by applying behavioral analyses, computational modeling and electroencephalography (EEG) analyses.

The first project is in collaboration with Dr. Ben Eppinger (Universität Greifswald).

The second project is in collaboration with Zoe Hilker (Max Planck School of Cognition).

Publications

Eppinger, B., Ruel, A., & Bolenz, F. (2023). Diminished state space theory of human aging. Perspectives on Psychological Science, 17456916231204811. PDF

Ruel, A. , Bolenz, F., Li, S-C., Fischer, A., Eppinger, B. (2022). Neural evidence for age-related deficits in the representation of state spaces. Cerebral Cortex, 1-14. PDF

Ruel, A., Devine, S., Eppinger, B. (2021). Resource-rational approach to meta-control problems across the lifespan. Wiley Interdisciplinary Reviews Cognitive Science. PDF

Ruel, A., Chiarella, S.S., Crivello, C., Poulin-Dubois, D. (2020) Concurrent Validity of the Modified Checklist for Autism in Toddlers (M-CHAT): Socio-cognitive and Verbal Skills in 18-Month-Old Infants. Journal of Autism and Developmental Disorders, 1-17. PDF

Poulin-Dubois, D., Hastings, P.D., Chiarella, S.S., Geangu, E., Hauf, P. Ruel, A., Johnson, A. (2018).The eyes know it: Toddlers’ visual scanning of sad faces is predicted by their theory of mind skills. PLOS ONE, 13(12), e0208524. PDF

Burnside, K., Ruel, A. , Azar, N., Poulin-Dubois, D. (2017). Implicit False Belief Accross the Lifespan: Non-replication of an Anticipatory Looking Paradigm. Cognitive Development, 46, 4-11. PDF