The Flynn effect is the fact that IQ scores have been constantly rising over time. There is some debate about whether this is real, or an artifact of the measuring process.
The history of poker is strong evidence that the effect is real. Poker has gotten more and more complicated over time. It started off very simple, but over time, more and more variants were added, all of which required more and more mental processing power to play.
It started with a 20-card deck, no draw, no revealed cards, and very simple scoring. In the early 1800's, the deck expanded to 52 cards, and the flush and then the straight were added to the game. Stud poker was added in the Civil war, and then wild cards were added, and then variants like lowball and high-low. People started to draw to change their hands, and then they started making the best hand out of seven or more cards. In the early 1900's, community cards were added, bringing a whole new level of strategy.
Remember that this is a game played for fun by ordinary people. Playing the common and popular poker variants and rules of the modern era takes a lot more brainpower than playing the old-style rules. I believe that the increasing complexity of poker happened because the brain of the average person was better equipped to handle the complexity. People got more raw IQ, and responded by increasing the strategic complexity of their entertainment so that it remained a good challenge.
Note, of course, that intelligence is not wisdom.