The sociology of jealousy deals with cultural and social factors that influence what causes jealousy, how jealousy is expressed, and how attitudes toward jealousy change over time. Anthropologists such as Margaret Mead have shown that jealousy varies across cultures. Cultural learning can influence the situations that trigger jealousy and the manner in which jealousy is expressed. Attitudes toward jealousy can also change within a culture over time. For example, attitudes toward jealousy changed substantially during the 1960s and 1970s in the United States. People in the United States adopted much more negative views about jealousy.