title: Remember the magic? How curiosity elicitation and the availability of extrinsic incentives shape memory formation and its neural mechanisms during encoding and early consolidation
Creators: name: Meliss, Stefanie
Publisher: name: University of Reading
Year: 2022

description: While curiosity – the intrinsic desire to know – is a concept central to the human mind and knowledge 
acquisition, scientific research targeting the understanding of curiosity is still in its infancy and has only 
recently begun to unravel it. Studies on information-seeking, a popular way to manipulate and measure 
curiosity in the lab, found that information shows similar rewarding properties as other, extrinsic 
rewards/incentives like food or money. Indeed, both can motivate behaviour and elicit a response in the 
dopaminergic structures of the neural reward circuits. The dopaminergic response further enhances 
encoding of information that is presented around its release by influencing dopamine-dependent cellular 
mechanisms of learning in the hippocampus. As such, extrinsic rewards/incentives and curiosity motivate 
and facilitate learning, illustrating their importance in educational contexts and knowledge acquisition.
Taken together, their large overlap in neural response and behavioural effects suggests that both may be
supported by common neural processes. However, this implies that their combined use would be
associated with sub-additive effects. On the other hand, if both were supported by differential neural 
effects, they could be used in an additive manner. Importantly, the question of how extrinsic 
rewards/incentives and curiosity interact in their effects on behaviour and cognition overall and memory 
in particular can only be answered if both effects are studied in conjunction rather than individually as 
often done in previous research. Another limitation stems from the way how studies thus far have 
investigated the effects of curiosity on memory, and in some cases, its interaction with extrinsic 
rewards/incentives, not only because they nearly exclusively all use the same paradigm, but more so 
because the paradigm itself has some inherent limitations that might affect how curiosity is 
conceptualised. 
The present work tries to address these gaps in the literature. In doing so, a new paradigm – the 
magic trick paradigm – was developed, in which curiosity and the availability of extrinsic incentives were
manipulated to measure their effects on encoding. In the magic trick paradigm, curiosity was elicited 
using short videos of magic tricks. Participants engaged in an orientation task combined with ratings of 
the “subjective feelings of curiosity” and performance therein was incentivised using a between-subject 
design. Unbeknown to the participants, their memory for the magic tricks was tested a week later.
Crucially, after behavioural pilots, the paradigm was adopted for usage with functional magnetic 
resonance imaging (fMRI) to be able to investigate the neural underpinnings of incentive- and/or 
curiosity-motivated incidental learning during encoding as well as early consolidation.
To the best of our knowledge, the associated fMRI dataset – the Magic, Memory, and Curiosity 
(MMC) Dataset – is the first of its kind, making it highly valuable to the nascent field investigating the 
effects of curiosity on memory because (1) fMRI data was acquired during the magic trick paradigm, but also before and after, allowing to study neural mechanisms underlying encoding as well as early 
consolidation, and (2) videos of magic tricks as dynamic stimuli allow for a plethora of analysis 
approaches to answer myriads of research questions. Chapter 2 describes the methods and procedures 
used to generate the MMC Dataset (N = 50), presented in a way that allows independent researchers to re-use it according to their needs. Additionally, high data quality comparable to other openly available 
datasets in the field has been demonstrated by performing data quality assessments and basic validation 
analysis. This further lays the groundwork for Chapters 3 and 4 where the fMRI data acquired during 
encoding and consolidation, respectively, will be used.
In Chapter 3, a meta-analytical approach was used to analyse the behavioural data from three 
studies (two behavioural studies and one fMRI study) using the magic trick paradigm to investigate the 
effects of curiosity, the availability of extrinsic incentives, and their interaction on memory. The main 
memory outcome was high-confidence recognition, a recollection-based memory measurement, but other 
indices were also examined to derive a more detailed picture. This revealed positive effects of curiosity 
and monetary incentives on encoding, in the absence of interaction effects. Exploratory analyses further 
showed that curiosity and monetary incentives might impact encoding differently, overall suggesting that 
the effects might be at least partially non-overlapping. Analysing the fMRI data acquired during the 
presentation of magic tricks using the intersubject synchronisation framework to account for the dynamic 
nature of the stimuli, we found that while the effects of curiosity on memory were located in the
hippocampus and dopaminergic brain areas, neither the effects of curiosity nor incentives themselves 
were found in the often-implicated reward network, but instead were associated with regions involved in 
processing uncertainly and attention. Likewise, the effects of curiosity on memory spread further across 
broad cortical and subcortical networks. Overall, this suggests that the subjective feeling of curiosity and 
its effects on memory recruits broad brain networks when investigated with dynamic stimuli, caveating a 
too narrow focus on a small list of regions-of-interest while there is yet so much more to be learned about 
the effects of curiosity on memory.
In Chapter 4, resting-state data acquired before and after learning was used to investigate changes 
in brain activity at rest following learning. The pre-learning rest data can be used as a baseline, allowing 
any changes from pre- to post-learning to be attributed to the learning experience itself. Because previous 
research has repeatedly pointed to similarities between extrinsic rewards/incentives and curiosity, our 
analysis focused on the change in resting-state functional connectivity between the dopaminergic 
midbrain and the anterior hippocampus, a dopaminergic consolidation mechanism previously reported in 
the context of extrinsically motivated learning. Contrary to our hypothesis, we did not find an overall 
change nor that individual differences therein predicted behavioural measures of learning. However, 
brain-behaviour correlations differed significantly depending on the availability of extrinsic incentives. In sum, this suggests that curiosity-motivated learning might be supported by different consolidation 
mechanisms compared to extrinsically motivated learning and that extrinsic motivation could re-configure 
resting-state networks supporting early consolidation.
Overall, this work adds to the literature by replicating the effects of curiosity on encoding. More 
importantly, however, this work suggests that the systems supporting extrinsically and curiosity-motivated learning might differ more than previously assumed, especially when investigating activity 
across the whole brain rather than focusing on a priori candidate regions implicated in dopaminergic 
effects. Indeed, our results allow for the possibility that other neurotransmitter play a role as well in 
extrinsically and curiosity-motivated learning, further highlighting the need for more research in the area.