Febe Demeyer

PhD student
Tiensestraat 102 - box 3711
3000 Leuven
Belgium

contact

I first obtained a Master’s Degree in Clinical Psychology at KU Leuven. Because I wanted to develop myself further as a researcher, I decided to obtain an additional Master’s Degree in Psychology, option Theory and Research. This program also involves a research internship, which I completed under the supervision of Prof. Eva Van den Bussche in the CogTex lab. After graduating in 2021, I stayed in the CogTex lab to pursue a PhD. In January 2022, I started as a PhD student to study cognitive control in aging. In October 2023, I was awarded a PhD Fellowship fundamental research by the Research Foundation Flanders. In my research, I explore whether insight problem solving remains stable or even improves with age. Insight can be defined as the sudden appearance of the solution into consciousness after being stuck solving a vexing problem. This phenomenon is accompanied by an affective response known as the “Aha!” experience. This research takes a unique perspective in a world that often emphasizes cognitive decline with age.

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journal-article
Demeyer, Febe;De Pue, Sarah;Aben, Bart;Verhaegen, Kirsten A;Meijer, Anne-Merel;Gillebert, Celine R;Van Den Bussche, Eva; 2026. Miyake Revisited: Validating the Factor Structure of an Open-Source Cognitive Control Test Battery. Journal of Cognition; 2026; Vol. 9; iss. 1

LIRIAS4394789
description
Cognitive control is a prerequisite for achieving goals in daily life. Miyake et al. (2000) distinguished three separable but correlated cognitive control functions in young adults: inhibition, shifting, and updating. This three-factor model was later adapted to a bi-factor model with a common factor and separate updating and shifting factors. Over the years, these models have been replicated in various young adult samples. However, other studies have failed to confirm these models. Furthermore, the variety of tasks used in these studies hampers replication of the underlying factor structure of cognitive control. The primary goal of this study was to address this issue of replicability by validating the factor structure of cognitive control functions using a new test battery based on often-used tasks, while offering full transparency about each step in the analysis process. This test battery comprises nine behavioral tasks measuring inhibition, shifting and updating. The factor structure was assessed in 247 young adults (84.21% female). Confirmatory Factor Analysis was used to test the one-factor model with a common cognitive control function, the three-factor model with separate but correlated cognitive control functions, and the bi-factor model. Our findings supported the three-factor model with correlated cognitive control functions as the best-fitting model, despite some fit indices yielding mixed evidence. Additionally, the test battery in this study is offered as an open-source and easily accessible resource. Finally, we offer a critical look on the field and provide recommendations for future use and adaptations of this test battery to increase its broad applicability.
Publisher: Ubiquity Press
Published
presentation
Demeyer, Febe;Stuyck, Hans;Gillebert, Céline;Van den Bussche, Eva; 2025. Insight Problem Solving in Older Adults: From Lab Tasks to Daily Life Challenges.

LIRIAS4395459
description

Published
presentation
Demeyer, Febe;Stuyck, Hans;Gillebert, Céline;Van den Bussche, Eva; 2025. The Impact of Cognitive Load on Insight and Analytical Problem Solving in Older Adults.

LIRIAS4395457
description

Published
preprint
Demeyer, Febe;De Pue, Sarah;Aben, Bart;Verhaegen, Kirsten;Meijer, Anne-Merel;Gillebert, Celine;Van den Bussche, Eva; 2025. Miyake revisited: The development of an open-source cognitive control test battery. PsyArXiv; 2025

LIRIAS4273534
description
<p>Cognitive control is a prerequisite for achieving goals in daily life. Miyake et al. (2000) distinguished three separable but correlated cognitive control functions in young adults: inhibition, shifting, and updating. This three-factor model was later adapted to a bi-factor model with a common cognitive control factor and separate updating and shifting factors. Over the years, these models have been replicated in various young adult samples. However, other studies have failed to confirm these models. Additionally, the variety of different tasks used in these studies hampers replication of the underlying factor structure of cognitive control. It becomes clear that this field would benefit from a uniform, easily accessible, open-source cognitive control test battery with a validated underlying factor structure and designed for the widest possible audience. For this reason, we developed a freely available cognitive control test battery comprising nine behavioral tasks measuring inhibition, shifting and updating. The underlying factor structure of this test battery was assessed in a group of 165 young adults. CFA was used to test the one-factor model with a common cognitive control function, the three-factor model with separate but correlated cognitive control functions, and the bi-factor model. Our findings supported the three-factor model with correlated cognitive control functions as the best fitting model. This test battery can lead to more uniformity in the field. In addition, we offer a critical look on the field and recommendations for future use and adaptations of the test battery.</p>
presentation
Demeyer, Febe;Gillebert, Céline;Stuyck, hans;Van den Bussche, eva; 2024. Cognitive Overload: Age-Dependent Shifts in Insight Problem-Solving.

LIRIAS4212164
description
As we age, analytical step-by-step problem-solving strategies that rely on executive functions decline. Alternatively, problems can also be solved using insight, which is characterized by a sudden realization of the solution (i.e., “Aha!” experience). Because insight is thought to be less dependent on executive functions, it may remain intact or even improve with age. We compared insight and analytical problem-solving between older adults and intelligence-matched young adults using the Compound Remote Associates test. In this task, participants receive word puzzles that can be solved analytically or with insight. Preliminary results show that older adults solved more problems with insight but fewer analytically compared to young adults. Next, we introduced an additional working memory load to study its impact on participants’ problem-solving performance. Both age groups solved fewer problems with insight in this dual-task condition compared to the single-task condition, but the decrease was larger for older adults. These results suggest that the advantage older adults have over young adults in insight problem-solving disappears when executive functions are additionally taxed.

Published
journal-article
Stuyck, Hans;Demeyer, Febe;Bratanov, Christo;Cleeremans, Axel;van den Bussche, Eva; 2024. Insight and non-insight problem solving: A heart rate variability study. Quarterly Journal Of Experimental Psychology; 2024; Vol. 77; iss. 7; pp. 1462 - 1484

LIRIAS4110130
description
Occasionally, problems are solved with a sudden Aha! moment (insight), while the mundane approach to solving problems is analytical (non-insight). At first glance, non-insight appears to depend on the availability and taxation of cognitive resources to execute the step-by-step approach, whereas insight does not, or to a lesser extent. However, this remains debated. To investigate the reliance of both solution types on cognitive resources, we assessed the involvement of the prefrontal cortex using vagally mediated heart rate variability (vmHRV) as an index. Participants (N = 68) solved 70 compound remote associates word puzzles solvable with insight and non-insight. Before, during, and after solving the word puzzles, we measured the vmHRV. Our results showed that resting-state vmHRV (trait) showed a negative association with behavioural performance for both solution types. This might reflect inter-individual differences in inhibitory control. As the solution search requires one to think of remote associations, inhibitory control might hamper rather than aid this process. Furthermore, we observed, for both solution types, a vmHRV increase from resting-state to solution search (state), lingering on in the post-task recovery period. This could mark the increase of prefrontal resources to promote an open-minded stance, essential for divergent thinking, which arguably is crucial for this task. Our findings suggest that, at a general level, both solution types share common aspects. However, a closer analysis of early and late solutions and puzzle difficulty suggested that metacognitive differentiation between insight and non-insight improved with higher trait vmHRV, and that a unique association between trait vmHRV and puzzle difficulty was present for each solution type.
Publisher: SAGE Publications
Published
preprint
Demeyer, Febe;De Pue, Sarah;Aben, Bart;Verhaegen, Kirsten;Meijer, Anne-Merel;Gillebert, Céline;Van den Bussche, Eva; 2024. Miyake revisited: The development of an open-source cognitive control test battery. PsyArXiv Preprints; 2024

LIRIAS4137116
description
Cognitive control is a prerequisite for achieving goals in daily life. Miyake et al. (2000) distinguished three separable but correlated cognitive control functions in young adults: inhibition, shifting, and updating. This three-factor model was later adapted to a bi-factor model with a common cognitive control factor and separate updating and shifting factors. Over the years, these models have been replicated in various young adult samples. However, other studies have failed to confirm these models. Additionally, the variety of different tasks used in these studies hampers replication of the underlying factor structure of cognitive control. It becomes clear that this field would benefit from a uniform, easily accessible, open-source cognitive control test battery with a validated underlying factor structure and designed for the widest possible audience. For this reason, we developed a freely available cognitive control test battery comprising nine behavioral tasks measuring inhibition, shifting and updating. The underlying factor structure of this test battery was assessed in a group of 165 young adults. CFA was used to test the one-factor model with a common cognitive control function, the three-factor model with separate but correlated cognitive control functions, and the bi-factor model. Our findings supported the three-factor model with correlated cognitive control functions as the best fitting model. This test battery can lead to more uniformity in the field. In addition, we offer a critical look on the field and recommendations for future use and adaptations of the test battery.
presentation
Demeyer, Febe;Stuyck, Hans;Gillebert, Céline;Van den Bussche, Eva; 2023. Is the Aha! Experience Ageless? Exploring Insight versus Analytical Problem Solving in Older Adults.

LIRIAS4134968
description
Challenges in the 21st century include keeping a growing population of older adults active on the work floor, where problem solving is vital. Typically, analytical step-by-step problem solving strategies, which rely on executive functions, decline with age (Thornton et al., 2013). However, we can also solve problems using insight, often accompanied by the Aha! experience. Insight is the sudden appearance of the solution after being stuck solving a problem (Bowden et al., 2005). As insight is expected to be less reliant on executive functions due to its more implicit nature, it might remain intact or even enhance in aging. To study this, we compared insight and analytical problem solving between young and older adults using the Compound Remote Associates test (Bowden & Jung-Beeman, 2003). Participants received word puzzles that can be solved both with insight and analytical problem solving. First results indeed indicate that whereas older adults perform worse when solving problems analytically, they solve more problems with insight compared to young adults. If insight problem solving proves to be enhanced in older adults, then stimulating insight, for example at the workplace, could benefit older adults’ problem solving skills.

Published
presentation
Demeyer, Febe;Stuyck, Hans;Gillebert, Céline;Van den Bussche, Eva; 2023. Better Insight When Growing Older? Adult Age Differences in Insight and Analytical Problem Solving.

LIRIAS4089166
description
One of the challenges of the 21st century is keeping a growing population of older adults professionally active. This is not trivial, as it is known that several cognitive functions decline with age. For example, the ability to suppress irrelevant information and flexibly update outdated information in service of a task. These executive functions (i.e., EF) are essential to solving problems explicitly step-by-step (i.e., analytical problem solving)—a vital skill in the 21st century workplace. As analytical problem solving declines with age, finding other skills that remain preserved is crucial. One such problem solving type that is less reliant on EFs due to its more implicit nature is insight. Insight solutions happen suddenly after being stuck solving a problem and are often accompanied by an affective Aha! experience. As insight is expected to be less reliant on EFs, it might remain intact or even enhance with aging. To study this, we compared insight and analytical problem solving between young and older adults using the Compound Remote Associates test. Participants receive word puzzles that can be solved both with insight and analytical problem solving. Three conditions were created by imposing a no, a low, or a high working memory load during problem solving. Data collection is ongoing and preliminary results indicate that older adults solve problems with insight faster than young adults. If insight problem solving proves to be enhanced in older adults, this could imply that triggering insight, for example, at the workplace, could benefit older adults’ problem solving skills.

Published
presentation
Demeyer, Febe;Stuyck, Hans;Gillebert, Céline;Van den Bussche, Eva; 2023. Behavioral Signatures of Insight Problem Solving in Older Adults.

LIRIAS4089165
description
One fundamental aspect of our working lives is solving problems. The most common way to solve problems is by using an explicit step-by-step strategy that relies on executive functioning (i.e., non-insight). When we age, this strategy declines (Artistico et al., 2003). It is therefore important to identify cognitive processes that remain intact or even enhance with aging to compensate for this decline (Brownell & Kelly, 2012). Insight problem solving might be such a cognitive skill. Insight is the sudden appearance of the solution after being stuck solving a problem (Bowden et al., 2005). As insight is expected not to rely heavily on executive functioning, insight might also be less age dependent. To study this, we will compare behavioral signatures of insight and non-insight between young and older adults at work using the Compound Remote Associates test (CRA; Bowden & Jung-Beeman, 2003). Here, participants receive word puzzles that can be solved both with insight and non-insight and they indicate whether each solution was obtained with insight or non-insight. Next to a no-load condition, two dual-task conditions are also created by imposing an additional low or a high working memory load during problem solving. Performance on the CRA is indexed by solution time, solution accuracy and the number of correctly solved puzzles. To predict performance, we will use (generalized) linear mixed models. We expect that older adults show decreased performance on puzzles solved with non-insight, as indexed by slower solution times, lower solution accuracy and fewer trials solved correctly with non-insight, as compared to young adults. Contrarily, we predict that their performance on puzzles solved with insight should be intact or even enhanced. We also expect a detrimental influence of working memory load on non-insight performance, but not on insight performance (Stuyck et al., 2022). Importantly, we expect this detrimental influence to be even larger for older adults.

Published
presentation
Demeyer, Febe;Stuyck, Hans;Gillebert, Céline;Van den Bussche, Eva; 2023. The Behavioral Signatures of Insight Problem Solving in Older Adults.

LIRIAS4089158
description
Insight is the sudden, effortless retrieval of the solution after being stuck solving a problem. In contrast, non-insight problem solving entails a conscious, effortful, step-by-step approach to obtain a solution. We aim to compare the behavioral signatures of insight and non-insight between young and older adults at work.

Published
preprint
Stuyck, Hans;Demeyer, Febe;Bratanov, Christo;Cleeremans, Axel;Van den Bussche, Eva; 2023. Insight and non-insight problem solving: A heart rate variability study. PsyArXiv; 2023

LIRIAS4079968
description
<p>Occasionally, problems are solved with a sudden Aha! Moment (insight), while the mundane approach to solve problems is analytical (non-insight). At first glance, non-insight appears to depend on the availability and taxation of cognitive resources to execute the step-by-step approach, whereas insight does not or to a lesser extent. However, this remains debated. To investigate the reliance of both solution types on cognitive resources, we assessed the involvement of the prefrontal cortex using vagally mediated heart rate variability (vmHRV) as an index. Participants (N = 68) solved 70 compound remote associates word puzzles solvable with insight and non-insight. Before, during, and after solving the word puzzles, we measured vmHRV. Our results showed that resting-state vmHRV (trait) showed a negative association with behavioural performance for both solution types. This might reflect inter-individual differences in inhibitory control. As the solution search requires one to think of remote associations, inhibitory control might hamper rather than aid this process. Furthermore, we observed, for both solution types, a vmHRV increase from resting-state to solution search (state), lingering on in the post-task recovery period. This could mark the increase of prefrontal resources to promote an open-minded stance, essential for divergent thinking, which arguably is crucial for this task. Our findings suggest that, at a general level, both solution types share common aspects. However, a closer analysis of early and late solutions and puzzle difficulty suggested that metacognitive differentiation between insight and non-insight improved with higher trait vmHRV, and that a unique association between trait vmHRV and puzzle difficulty was present for each solution type.</p>
journal-article
Dejonckheere, Egon;Demeyer, Febe;Geusens, Birte;Piot, Maarten;Tuerlinckx, Francis;Verdonck, Stijn;Mestdagh, Merijn; 2022. Assessing the reliability of single-item momentary affective measurements in experience sampling. Psychological Assessment; 2022; Vol. 34; iss. 12; pp. 1138 - 1154

LIRIAS3806089
description
Emotion researchers that use experience sampling methods (ESM) study how emotions fluctuate in everyday life. To reach valid conclusions, confirming the reliability of momentary emotion measurements is essential. However, to minimize participant burden, ESM researchers often use single-item measures, preventing a reliability assessment of people's emotion ratings. Furthermore, because emotions constantly change, checking reliability via conventional test-retest procedures is impractical, for it is impossible to separate measurement error from meaningful emotional variability. Here, drawing from classical test theory (CTT), we propose two time-varying test-retest adaptations to evaluate the reliability of single-item (emotion) measures in ESM. Following Method 1, we randomly repeat one emotion item within the same momentary survey and evaluate the discrepancy between test and retest ratings to determine reliability. Following Method 2, we introduce a subsequent, shortly delayed retest survey and extrapolate the size of test-retest discrepancies to the hypothetical instance where no time between assessments would exist. First, in an analytical study, we establish the mathematical relation between observed test-retest discrepancies and measurement error variance for both methods, based on common assumptions in the CTT literature. Second, in two empirical studies, we apply both methods to real-life emotion time series and find that the size of error in people's emotion ratings corresponds with almost a 10th of the scale, comprising around 27% of the total variability in participants' affective responses. Consequently, disregarding measurement error in ESM is problematic, and we encourage researchers to include a test-retest procedure in their future studies when relying on single-item measures. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
Publisher: American Psychological Association
Published
presentation
Demeyer, Febe;De Pue, Sarah;Gillebert, Céline;Van den Bussche, Eva; 2022. Miyake revisited 2.0: Further adaptations to a cognitive control test battery. Publisher: Ubiquity Press

LIRIAS4009743
description
Cognitive control allows us to continuously hold multiple contents in working memory, inhibit inappropriate or automatic responses and switch attention from one source of information to another. Miyake et al. (2000) found three separable functions of cognitive control that share some underlying commonality: updating, inhibition and shifting. Given the limited construct validity of single tasks tapping into these functions, we assessed a wider set of cognitive control subcomponents, using confirmatory factor analysis (CFA). As the CFA did not converge and some tasks failed to load on their assumed underlying subcomponent, we have now adapted the test battery. Preliminary CFA results support the 3-factor structure compared to a 1-factor structure, as indexed by several fit indices. The tasks also load better on their assumed underlying subcomponent. Ultimately, we aim to develop a valid and open-access test battery that can also be used in future developmental and clinical studies.

Published
presentation
Demeyer, Febe;De Pue, Sarah;Gillebert, Céline;Van den Bussche, Eva; 2022. Miyake revisited 2.0: Further adaptations to a cognitive control test battery.

LIRIAS4009742
description
To achieve our goals, our cognitive system needs to hold multiple contents in working memory, inhibit inappropriate or automatic responses and switch attention from one source of information to another. These cognitive functions are also referred to as “cognitive control”. Miyake et al. (2000) found three separable functions of cognitive control in young adults that share some underlying commonality: updating, inhibition and shifting. In experimental studies on cognitive control, often only one of these cognitive control functions is measured using only one experimental task. However, given the limited construct validity of these tasks, multiple aspects of cognitive control are usually needed to perform these tasks successfully. For this reason, we assessed a wider set of cognitive control subcomponents using a test battery existing of nine experimental tasks in a group of 138 students, in line with Miyake et al. Using confirmatory factor analysis (CFA), we assessed the underlying factor structure of these tasks. However, the CFA did not converge and some tasks failed to load on their assumed underlying subcomponent. Therefore, we have now adapted the test battery and re-ran the study in a new sample of 201 students. Preliminary CFA results support the 3-factor structure compared to a 1-factor structure, as indexed by several fit indices, and the tasks load better on their assumed underlying subcomponents. Ultimately, we aim to develop a valid, uniform and open-access test battery. Additionally, this test battery will be used in future developmental and clinical studies.

Published