Unexpected positive outcomes increase a person’s willingness to take gambling risks, according to a new study.

Research shown that being in a good mood causes people to take riskier bets, but a new study has drawn a direct line between the arrival of an unforeseen positive event and increases in people’s willingness to take a chance on winning a prize.

New York University researcher Ross Otto led a study recently published in the journal Psychological Science that identified a direct link between increased lottery sales and the unexpected arrival of a sunny day or a surprise win by a local sports team.

In order to factor out the influence of occasional mad jackpot rushes – such as this month’s Powerball frenzy – the study used statistics of non-jackpot lottery sales (like instant-win scratch tickets) in New York City covering the years 2011 and 2012,