A recession is a cash/dollar bubble.

First cash/dollars are considered bad so they collapse in price. When the psychology shifts, suddenly the dollar climbs in value and itself bubbles over, causing a recession.

Not sure if you're referring to dollars as an alternative to other forms of cash (e.g., treasuries, money market funds, etc.) or as an alternative to other currencies (e.g., Euro, Yen, etc.). If it's the latter, then I think we've seen recessions and booms where the opposite happens, depending on the balance of payments situation.