Please tell us more Jane.
Why is the phrase 'cognitive function' troubling you? Would you like me to spell it some other way?
If you're having trouble with that, there's little point in me referring you to the research papers on PubMed on this subject. I suggest if you'd like to know more, have a word with your local specialist in aviation medicine. They're paid to educate you. I'm not.
I'm simply here to tell you that active pilots shouldn't drink alcohol. It's not big and it's not clever. End of.