On the June 17, 2016 edition of 99% Invisible.

In September 1958, Bank of America began an experiment—one that would have far reaching effects on our lives and on the economy. After careful consideration, they decided to conduct this experiment in Fresno, California. The presumption was that no one was paying much attention to Fresno, so if the plan failed, it wouldn’t get a lot of media attention.

Bank of America sent out 60,000 pieces of mail to people in Fresno. Inside was a little plastic object that has become in equal parts emblematic of opportunity, convenience, and debt.

It was a card offering a $500 line of credit.

Before credit cards, corner bars and other local businesses allowed patrons to keep open tabs, using ledger books to record amounts owed. Some stores assigned account numbers to customers, or even gave them “charge tokens,” or single-shop credit cards.

For bigger purchases at stores not offering in-house credit, consumers had to get individual loans to buy expensive things like large appliances [...]