Advocates behind a proposed ballot question that could potentially decriminalize certain plant-based hallucinogens, a.k.a. psychedelics, are gathering signatures to put the question in front of voters on election day in November. If successful, people over 21 can use a limited amount of substances like magic mushrooms without worry of criminal penalties from the state. This week, The Common will present a three-part series that explores the past, present and future of psychedelics and what their decriminalization could mean for Massachusetts. Today, we’ll delve into the past with Andrew Green Hannon, an adjunct lecturer at Emerson College who holds a Ph.d from Yale University’s American Studies Program. His research focuses on the American counterculture and the New Left, and he is a local expert on psychedelics. Greater Boston’s daily podcast where news and culture meet.