Testosterone: activation or organization of spatial cognition?

Area of Science:

• Neuroendocrinology
• Cognitive Neuroscience
• Human Behavior

Background:

• Animal studies suggest testosterone impacts brain organization and behavior.
• The translation of these effects to the human brain remains unclear.
• Distinguishing between prenatal and current testosterone's influence is crucial.

Purpose of the Study:

• To clarify the relative contributions of prenatal and current testosterone to human cognitive function.
• To investigate the relationship between testosterone indices and specific cognitive tasks.
• To differentiate the impact of early-life versus adult hormone levels on cognition.

Main Methods:

• Sixty-nine subjects completed computerized tasks assessing mental rotation, targeting, figure-disembedding, and perceptual discrimination.
• Free testosterone levels were measured in saliva samples.
• Second-to-fourth finger length ratios (2D:4D) were used as a proxy for prenatal testosterone exposure.
• Stepwise regression analyses were employed to correlate performance with testosterone indices.

Main Results:

• Sex was the exclusive predictor for mental rotation performance.
• The second-to-fourth finger length ratio (2D:4D) uniquely predicted targeting performance with a curvilinear relationship.
• 2D:4D also linearly predicted figure-disembedding performance.
• Current free testosterone levels did not significantly predict performance on any tested cognitive task.

Conclusions:

• Prenatal testosterone exposure, as indexed by 2D:4D, plays a substantial role in shaping specific cognitive abilities in humans.
• Current testosterone levels appear to have minimal impact on the cognitive functions assessed.
• These findings highlight the lasting effects of early hormonal environments on cognitive specialization.