Half the participants drank hot cocoa high in antioxidant flavanol, while the other half drank flavanol-poor hot cocoa. (There is substantial evidence that consuming cocoa flavanols helps circulation and heart health.)
The participants were asked not to consume any other products containing chocolate during the study.
The team tested the participants' memory and thinking skills before and after using a set of standard tests.
Using ultrasound, they also measured neurovascular coupling (the blood flow response to brain activity) as the participants completed the mental tests.