In 1948, Lasswell proposed that media served four functions: surveillance, correlation, entertainment, and cultural transmission. Bulmer and Katz expanded on this, proposing the "uses and gratifications" theory that individuals choose media to fulfill certain needs like diversion, personal relationships, personal identity, and surveillance. For example, a magazine like Top of the Pops allows readers to relax and learn about celebrities for diversion, feel connected through gossip for relationships, see reflections of themselves for identity, and get celebrity updates for surveillance. The uses and gratifications theory remains influential in understanding why people engage with various media.