A study from York University reveals that testosterone levels, rather than s*x alone, may be the key factor determining performance in complex motor tasks requiring the integration of thought and action. The findings shed light on persistent performance gaps in activities ranging from marksmanship to surgical procedures.
Researchers at York University’s School of Kinesiology and Health Science examined 36 working-age adults to understand what drives performance differences in tasks requiring cognitive-motor integration.
Their study, published in Frontiers in Human Neuroscience, found that testosterone concentrations significantly predicted how well participants performed complex hand-eye coordination tasks.
The research team, led by Dr. Lauren E. Sergio, tested participants on two types of movements: standard direct tasks where hand and eye movements align naturally, and non-standard tasks requiring the brain to process rules while coordinating vision and movement. In the more complex scenarios, participants viewed targets on a vertical screen but moved their hands on a horizontal surface, with visual feedback rotated 180 degrees.
“Higher levels of testosterone were predictive of significantly faster movement time, after controlling for age,” the study reported. Participants with elevated testosterone also demonstrated shorter path lengths and smaller accuracy errors when cognitive demands increased.
Brain Structure and Performance
The relationship between testosterone and performance appears linked to brain anatomy. Using MRI scanning, researchers found that testosterone’s effects on movement control related to grey matter thickness and volume in regions responsible for visuomotor processing.
“These data suggest that underlying brain networks controlling simultaneous thought and action may differ as a function of sex st**oid hormone concentrations,” the researchers concluded.
The brain regions showing these relationships included the posterior cingulate cortex, superior temporal gyrus, and middle frontal gyrus. Individuals with higher cortical thickness in these areas combined with elevated testosterone showed the strongest performance advantages.
While the study confirmed that males outperformed females on the complex tasks, measuring faster movement times and shorter path lengths, the research went further by identifying testosterone as the biological mechanism underlying these differences.
“After accounting for age effects, testosterone was a significant predictor of cognitive-motor integration performance in this group,” according to the findings. Notably, estradiol and progesterone showed no relationship to performance on either standard or complex tasks.
The average testosterone concentration for males measured 173.76 pg/ml compared to 91.37 pg/ml for females. This hormonal difference corresponded with measurable performance gaps: males completed the complex task with movement times averaging 1,050.78 milliseconds versus 2,051.35 milliseconds for females.
These findings have direct applications for understanding performance in high-stakes environments. Military marksmanship, surgical precision, and piloting all require the integration of visual information with motor control under rule-based constraints.
The research also revealed that 90.8% of trials were successful in standard conditions across all participants, but success rates dropped to 63.8% when cognitive demands increased. Males maintained higher success rates even as task complexity escalated.
“The planning and execution of non-standard movements requires the activation of cortico-subcortical brain networks, particularly frontoparietal-cerebellar networks,” the study explained. These networks contain abundant androgen receptors, allowing testosterone to influence neural processing directly.
The Aging Factor
Age showed minimal impact on performance in this working-age population, with participants ranging from 30 to 65 years old. The primary age-related change was an increase in directional errors, with older participants making more initial movement mistakes.
“Small performance declines emerge in the working-age years,” researchers noted, though testosterone remained the dominant predictor of capability regardless of age within this demographic.
The study suggests that testosterone may help maintain cognitive-motor integration abilities as people age. Previous research has linked declining testosterone with motor dysfunction and cognitive changes, though this study focused on currently healthy adults.
Testosterone appears to enhance performance through multiple pathways. The hormone has been shown to increase dendritic spine density in sensorimotor cortices, improving communication between neurons. It also modulates neurotransmitter systems and supports larger motor neurons.
“Testosterone can both improve the structural integrity of the brain networks underlying complex movement and act as a neuromodulator,” the researchers explained. The hormone may facilitate neuronal excitability in corticospinal pathways controlling voluntary hand movements.
Study Design and Validation
Participants performed tasks on touchscreen devices, sliding their fingers to move cursors between targets. In standard conditions, they interacted directly with a vertical screen. Complex conditions required them to move their hand on a horizontal surface while viewing targets vertically, with reversed visual feedback.
The research team collected saliva samples to measure hormone concentrations and used MRI to assess brain structure. They validated their imaging techniques by comparing scans taken with different equipment setups, finding strong reliability across measurement methods.
Multiple regression analyses controlled for age while examining hormone effects. The statistical approach allowed researchers to isolate testosterone’s impact from other variables that might influence motor performance.
Clinical and Practical Considerations
The findings have implications for training programs, workplace accommodations, and personnel selection in fields requiring precise motor control under cognitive load. Understanding the biological basis of performance differences may help organizations optimize training approaches for different individuals.
For females entering traditionally male-dominated fields requiring these skills, the research suggests that task design modifications or extended training periods might help compensate for hormonal differences in motor control networks.
The study also points toward potential interventions. If testosterone levels influence performance through modifiable brain structures, targeted cognitive or physical training might strengthen these neural networks regardless of hormone status.
Future Directions
The research team identified several areas requiring further investigation. Larger studies with greater statistical power could examine interactions between multiple factors simultaneously. Longitudinal designs tracking individuals over time would clarify how hormone changes affect performance trajectories.
Questions remain about whether these relationships hold in clinical populations or under different types of cognitive-motor demands. The team also suggested examining whether hormone-related performance differences appear in functional brain activity during task execution, not just in resting brain structure.
“An important next step is to include neuroendocrine status when taking into account personal differences, in order to comprehensively understand simple and complex movement control during healthy and pathological aging,” the researchers concluded.
