Focus, memory and reaction time - does my morning cup of coffee help me get my work done?

Will coffee before taking my exam help or hinder me? What about if I'm up late gaming - will coffee help my reaction times? And which jobs could benefit the most from regular caffeine dosing?

Two weeks ago we had a look at caffeine's impact on physical performance and this week Brendan, Aaron and Chris wrap up by discussing caffeine's impact on our cognitive performance.

References:

Reaction times https://www.sciencedirect.com/science/article/abs/pii/S0031938420303450
Memory https://www.josam.org/josam/article/view/76
Focus https://www.sciencedirect.com/science/article/abs/pii/S1053810019303435?via%3Dihub
Non-caffeine https://www.mdpi.com/2072-6643/10/10/1386/pdf