what
Explanation
The comic shows a man holding flowers, apparently celebrating his 20th wedding anniversary, when his wife cheerfully delivers shocking news: "Turns out you can have a happy marriage without the wife feeling any genuine affection. Very counterintuitive, but that's science!"
The man reacts with an enormous, alarmed "WHAT?!" The caption below reads: "On their 20th Anniversary, Dave was informed he was married to a placebo wife."
The joke operates on multiple levels. First, it borrows the concept of a "placebo" from medical science -- a placebo is an inert treatment (like a sugar pill) that has no actual therapeutic effect, yet patients often report feeling better because they believe they are receiving real medicine. The comic extends this concept absurdly to marriage: the "placebo wife" has no genuine affection, yet the marriage functioned perfectly well for 20 years, suggesting the husband's belief that he was loved was sufficient to sustain the relationship.
Second, the wife's delivery is hilariously clinical and detached. She presents the devastating revelation that she has never felt genuine affection as though it were an interesting scientific finding -- "very counterintuitive, but that's science!" -- treating the emotional devastation of her husband as a mere data point. This mirrors the way scientists might discuss surprising experimental results with professional detachment.
The comic also satirizes the replication crisis and the sometimes absurd conclusions drawn from social science research, where counterintuitive findings are presented as authoritative truth. There is also an undercurrent of dark humor about marriage itself -- the idea that one partner might be completely oblivious to the other's emotional state for decades.