# Now it’s your turn!: Eye blink rate in a Jenga task modulated by interaction of task wait times, effortful control, and internalizing behaviors

## TL;DR

The study explores how children's eye blink rate changes during a Jenga-like game, influenced by their effortful control and internalizing behaviors.

## Contribution

The novel contribution is using a naturalistic Jenga task to examine how dopamine activity, as indexed by eye blink rate, is modulated by effortful control and internalizing behaviors.

## Key findings

- A significant 3-way interaction was found between effortful control, internalizing behaviors, and wait period duration on eye blink rate.
- Children with high effortful control and low internalizing behaviors showed decreased eye blink rate as wait times increased.
- The findings suggest task-related changes in dopamine activity vary with individual differences in effortful control and internalizing behaviors.

## Abstract

Dopamine is a versatile neurotransmitter with implications in many domains, including anxiety and effortful control. Where high levels of effortful control are often regarded as adaptive, other work suggests that high levels of effortful control may be a risk factor for anxiety. Dopamine signaling may be key in understanding these relations. Eye blink rate is a non-invasive proxy metric of midbrain dopamine activity. However, much work with eye blink rate has been constrained to screen-based tasks which lack in ecological validity. We tested whether changes in eye blink rate during a naturalistic effortful control task differ as a function of parent-reported effortful control and internalizing behaviors. Children played a Jenga-like game with an experimenter, but for each trial the experimenter took an increasingly long time to take their turn. Blinks-per-second were computed during each wait period. Multilevel modeling examined the relation between duration of wait period, effortful control, and internalizing behaviors on eye blink rate. We found a significant 3-way interaction between effortful control, internalizing behaviors, and duration of the wait period. Probing this interaction revealed that for children with low reported internalizing behaviors (-1 SD) and high reported effortful control (+1 SD), eye blink rate significantly decreased as they waited longer to take their turn. These findings index task-related changes in midbrain dopamine activity in relation to naturalistic task demands, and that these changes may vary as a function of individual differences in effortful control and internalizing behaviors. We discuss possible top-down mechanisms that may underlie these differences.