Lots of great answers here.
I'll just coin in that as someone with Cog Psy degree, I have recently reunited with my uni classmates, and we were catching up, and they asked if I use any of the knowledge from my degree for my work and that's when I realized I use it all the time, daily.
What is useful the most for me are two things: neuroscience and neurophysiology and the basic psychology of human activity, motivation, backgrounds, emotions, models of mind and so on.
This all is giving me an intuitive picture of how the mind, both individual and social, works, and as other people said, it is easy for me to formalize it, put it in words and communicate to my teams and my clients.
It also gives me an opportunity to see the user needs of the application from the deeper perspective, and often I can contribute to and enhance the business strategy and brand communication with ideas why the app should or shouldn't work and be positioned a certain way.
And it's tremendously helpful in running teams and keeping the team in balance — I see the social dynamics and I can act on them faster than anybody else, for example, let people blow off steam instead of going into the interpersonal conflict, or see which stakeholders don't trust each other, and fix their communication.
Obviously, this is not UX per se, but as a Senior UX who grew to be a Product Manager, it's very helpful.