This paper considers the standard linear public goods game under two experimental conditions. The positive-frame condition is the regular public goods game that experimental economists have studied in the past. This frames the subject's choice as contributing to a public good, which will have a positive benefit to other subjects. The second condition is the negative-frame condition. The incentives of this game are identical to the positive-frame condition. However, this time a subject's choice is framed as purchasing a private good which, since the opportunity cost is the purchase of the public good, makes the other subjects worse off. The result is that subjects in the positive-frame condition are much more cooperative than subjects in the negative-frame condition. This indicates that much of the cooperation observed in public goods experiments is due to framing, and that the warm-glow of creating a positive externality appears to be stronger than the cold-prickle of creating a negative externality.