) and thus crucial for development. In this study, we show substantial changes in exploration between childhood and adolescence. Our results thus clearly expand the previous studies that either only focused on exploration in children and infants (Bonawitz et al., 2011; Bonawitz et al., 2012; Cook et al., 2011; Gweon et al., 2014; Meder et al., 2021; Pelz et al., 2015), or compared adults to minors without tracing development throughout childhood and adolescence (Schulz et al., 2019; Somerville et al., 2017). Moreover, to our knowledge we are the first to compare between multiple computationally complex and simple exploration strategies and show a specific development of value-free random exploration in the transition from childhood to adolescence. Our findings thus demonstrate that youths deploy a multitude of exploration strategies and that the reliance on these strategies dynamically changes before reaching adulthood.
Value-free random exploration is used early in development because it does not rely on heavy computation skills, which only mature later on (Gopnik et al., 2015; Thompson-Schill et al., 2009). This is in line with the fact that it relies on noradrenaline functioning (Dubois et al., 2021), as noradrenaline is expressed during early stages of development (Saboory et al., 2020), making it available for use from a very young age. Additionally, the noradrenergic system is an old and well-preserved neurotransmitter system across evolution (Bauknecht & Jékely, 2017; Kass-Simon & Pierobon, 2007), suggesting that value-free random exploration may be a phylogenetically old strategy.
Interestingly, ADHD scores were weakly correlated with model fit, meaning that subjects with higher ADHD scores had a somewhat lower (absolute) model fit. A lower model fit, however, does not mean that the model is worse per se for these subjects (especially if the relative performance compared with other models remains similar). Rather, it can be the consequence of a somewhat more stochastic overall responding. A most recent study (Moutoussis et al., 2021) indeed identified a cognitive acuity factor across multiple computational tasks, which also was accounting for difference in absolute model fit.
Importantly, whilst such a value-free random exploration strategy can be useful for exploration under certain circumstances, the question arises how specific this is and whether this does not simply capture inattention, especially with relation to ADHD. In our data, we observe that this form of exploration is condition specific, i.e. it increases in the long vs short horizon condition both in the behavioural measure (frequency of picking the low-value bandit) and the model parameter (ϵ-greedy parameter). Such a condition-specific effect is unlikely to be explained by mere inattention. This is particularly relevant for our ADHD finding, where we find the effect primarily in the long (but not in the short) horizon. Similar to previous studies using comparable tasks (Somerville et al., 2016; Wilson et al., 2014; Wu et al., 2018; Zajkowski et al., 2017), a single model was used to model both decision horizon conditions. However, future studies could attempt to fit both horizons separately to see whether the model used is context dependent. It is important to note that in this sample the two complex exploration strategies (i.e., UCB and Thompson) were difficult to distinguish. However, they were associated to similar heuristics usage, which is what we were interested in here.
Taken together, our results suggest that value-free random exploration is a simple exploration strategy that is of great benefit when cognitive resources are still limited during earlier stages of development. As we grow older and our experience expands, it is evolutionary useful to incorporate our knowledge in decision making and therefore lessen their use of value-free random exploration. Such a process seems to be imbalanced in youths with ADHD symptoms, as they show increased levels of value-free random exploration, which leads to suboptimal decision making.
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The authors thank the children, adolescents, their schools (especially Sydney Russell School, Baden Powell School and Holmleigh Primary School), and the families for taking part in this study. They are grateful to Shona Waters for helping with data collection.
All relevant resources are publicly available at: https://github.com/MagDub.
M.D. is a predoctoral fellow of the International Max Planck Research School on Computational Methods in Psychiatry and Ageing Research. The participating institutions are the Max Planck Institute for Human Development and the University College London (UCL). TUH is supported by a Sir Henry Dale Fellowship (211155/Z/18/Z; 211155/Z/18/B; 224051/Z/21) from Wellcome & Royal Society, a grant from the Jacobs Foundation (2017-1261-04), the Medical Research Foundation, a 2018 NARSAD Young Investigator grant (27023) from the Brain & Behavior Research Foundation, and a Philip Leverhulme Prize from the Leverhulme Trust (PLP-2021-040). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 946055). The Max Planck UCL Centre is a joint initiative supported by UCL and the Max Planck Society. The Wellcome Centre for Human Neuroimaging is supported by core funding from the Wellcome Trust (203147/Z/16/Z). For the purpose of Open Access, the authors have applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission.
The UCL research ethics committee approved the study.
The Federal Government has been advised by the Economic Sustainability Committee (ESC) led by Vice President, Yemi Osinbajo has advised to suspend the National Youth Service Corps (NYSC) orientation camp exercises for two years.
It is unclear whether the federal government will take the recommendation of the Economic Sustainability Committee to suspend the orientation camp exercises.
Dissembled DJ-1 high molecular weight complex in cortex mitochondria from Parkinson's disease patients.
Mol Neurodegener.2009 Jun 04 ; 4():23.
The PARK7 gene encodes a protein, DJ-1, with several functions such as protection of cells from oxidative stress, sperm maturation and fertilization, and chaperone activity. Mutations in the PARK7 gene are associated with autosomal recessive early-onset Parkinson's disease (PD). DJ-1 has been reported to be expressed in multiple cells in the central nerve system. Here, by using both native and denatured Western blots, we examined levels of total DJ-1 and high molecular weight complexes of DJ-1 (HMW) in both the substantia nigra and cortex from rapidly autopsied 18 PD and 9 non-pathological control (NPC) brains. We have discovered that the level of total DJ-1 protein is significantly reduced in the substantia nigra in brains of sporadic PD patients. Moreover, in the PD cortex mitochondria fraction, the HMW DJ-1 complex is significantly lower than in the NPC. These results suggest abnormal DJ-1 expression levels and DJ-1 complex changes may contribute to PD pathogenesis.
[Review] Linking DJ-1 to neurodegeneration offers novel insights for understanding the pathogenesis of Parkinson's disease.
Association of DJ-1 and parkin mediated by pathogenic DJ-1 mutations and oxidative stress.
The role of DJ-1 in the pathogenesis of Parkinson's disease.Eighteen-year-old Elena Myers made history on Saturday, March 17, when she became the first female to win a professional motorsports event at Daytona International Speedway with her victory in SuperSport Race 2.
Competing for Team SuzukiScoopFans Racing, Myers took the checkered flag in the season-opening round of the 2012 AMA Pro Motorcycle-Superstore.com SuperSport Series at Daytona International Speedway in Daytona Beach, Florida.
Riding the Suzuki GSX-R600, Myers started the weekend by carding a front-row grid position during qualifying. In Friday’s AMA Pro SuperSport race, she became reacquainted with the Daytona track and its notorious banking, running up front in a podium position for several laps before finishing a respectable sixth. Then, on Saturday morning, Myers pulled out all the stops and battled for a podium