A sex worker is a person who is employed in the sex industry. The term is used in reference to all those in all areas of the sex industry, including those who provide direct sexual services as well as the staff and management of such industries. Some sex workers are paid to engage in sex acts or sexually explicit behavior which involves varying degrees of physical contact with clients (prostitutes and some but not all professional dominants); pornographic models and actors engage in sexually explicit behavior which is filmed or photographed. Phone sex operators have sexually-oriented conversations with clients, and may do verbal sexual roleplay. Other sex workers are paid to engage in live sexual performance, such as webcam sex and performers in live sex shows. Some sex workers perform erotic dances and other acts for an audience. These include: striptease, go-go dancing, lap dancing, neo-burlesque, and peep shows. Sexual surrogates work with psychoanalysts to engage in sexual activity as part of therapy with their clients. Thus, although the term sex worker is sometimes viewed as a synonym or euphemism for "prostitute", it is more general. Sex worker can refer to individuals who do not directly engage in sexual activity such as pole dancers, sex toy testers, and strip club managers. Another example of sex workers that would not fall under the term prostitute would be an adult talent manager, who negotiates and secures pornographic roles for clients. There are also erotic photographers who shoot and edit for adult media and porn reviewers who watch and rate adult films. Some people use the term sex worker to avoid invoking the stigma associated with the word prostitute. Using the term sex worker rather than prostitute also allows more members of the sex industry to be represented and helps ensure that individuals who are actually prostitutes are not singled out and associated with the negative connotations of prostitute. In addition, choosing to use the term sex worker rather than prostitute shows ownership over the individuals' career choice. Some argue that those who prefer the term sex worker wish to separate their occupation from their person. Describing someone as a sex worker recognizes that the individual may have many different facets, and are not necessarily defined by their job. According to one view, sex work is different from sexual exploitation, or the forcing of a person to commit sexual acts, in that sex work is voluntary "and is seen as the commercial exchange of sex for money or goods". In an attempt to further clarify the broad term that sex work is, John E. Exner, an American psychologist, worked with his colleagues to create five distinct classes for categorizing sex workers. One scholarly article details the classes as follows: "specifically, the authors articulated Class I, or the upper class of the profession, consisting of call girls; Class II was referred to as the middle class, consisting of 'in-house girls' who typically work in an establishment on a commission basis; Class III, the lower middle class, were 'streetwalkers' whose fees and place of work fluctuate considerably; Class IV sex workers have been known as 'commuter housewives', and they are typically involved in sex work to supplement family income; and Class V consists of 'streetwalker addicts', or 'drugs-for-sex streetwalkers' who are considered the lower class of the profession."