Psychologists Petty & Cacioppo found that there are two ways of processing persuasive messages: (1) to focus on the content and quality of the message (central processing), or (2) to focus instead on external cues (such as the source of the message) and to disregard its content (peripheral processing). "When participants use the central/systematic route of responding to message content, they tend to be persuaded more by strong arguments, and less by weak arguments. However, the strength of the argument matters less when the peripheral route is chosen. In that case, other "peripheral" factors, such as the credibility of the source of the message or the intention of the communicator become important in the persuasive process." Petty and Cacioppo suggest that negative affect should lead to more central processing and positive affect to more peripheral processing. That is, "In happy moods, people tend to be persuaded equally by strong and weak arguments, whereas in sad moods, people are persuaded only by strong arguments and reject weak arguments." Said otherwise, positive moods increase the reliance on positive beliefs, whereas negative moods encourage the updating of beliefs in the light of new, significant data.