You probably saw the story-- "former Drexel University professor faces criminal charges after allegedly stealing $185,000 in research grant money," using much of it at a strip club. Sure, it's proverbial, everyone knows about this phenomenon. "Thinking with the little head" and so on. Remember four star general David Petraeus--also former head of the CIA--pleading guilty to giving his mistress classified secrets? And Petraeus is normally a very bright fellow. We often hear of intelligent men in the sciences, in mentally demanding computer work, and in other cognitively demanding fields, getting in trouble for sexual harassment. They should be too smart to blunder into that cloddish behavior--but they seem to abandon their smarts when women are around.
There are countless examples from history. And a "honeytrap", using sexy women to manipulate men into revealing state secrets, is a standard of espionage.
I know from personal experience that just being around a woman can make a man stupider--and it's even been tracked in studies as cited in this Psychology Today piece, Interacting With Women Makes Men Stupid: "...40 male participants tended to perform worse on a cognitive task ... following the mixed-sex interaction compared to the same-sex interaction..." Apparently some of it has to do with the brain working overtime to impress the opposite sex. A man's brain just can't handle a lot of generalized cognition when it's consumed by "Gotta Make Her Think I'm Cool."
The studies show the drop in cognition, in the mating context, is more striking in men than women. Are you surprised? And men seem more likely to get mixed up about what interactions are actually about mating. "Compared to women, men are more likely to consider mixed-sex interactions in terms of a mating game...men in particular might therefore be prone to engage in effortful and cognitively demanding attempts to impress an opposite-sex partner."
It's a phenomenon found across species. Consider the bower bird, who must construct elaborate housing in order to be selected by a female for mating--I have noticed that offering elaborate, costly habitat is also a plus in human courtship--or the intricate mating dances of the peacock spider or the seahorse. These creatures have no cognitive room to spare when they're engaging in elaborate mating displays and we don't seem to have much left either, when we're trying to mate. Nature wants us to really focus on this mating thing--and doesn't seem to care if it's to the detriment of our intelligence. But then--nature, generally, doesn't seem to care what we think...