Manifest function refers to the intended function of social policies, processes, or actions that are consciously and deliberately designed to be beneficial in its effect on society. Meanwhile, a latent function is one that is not consciously intended, but that, nonetheless, has a beneficial effect on society. Contrasting with both manifest and latent functions are dysfunctions, which are a type of unintended outcome that is harmful in nature.
Robert Merton's Theory of Manifest Function
American sociologist Robert K. Merton laid out his theory of manifest function (and latent function and dysfunction too) in his 1949 book "Social Theory and Social Structure". The text - ranked the third most important sociological book of the 20th century by the International Sociological Association - also contains other theories by Merton that made him famous within the discipline, including the concepts of reference groups and self-fulfilling prophecy.
As part of his functionalist perspective on society, Merton took a close look at social actions and their effects and found that manifest functions could be defined very specifically as the beneficial effects of conscious and deliberate actions. Manifest functions stem from all manner of social actions but are most commonly discussed as the outcomes of the work of social institutions like the family, religion, education, and the media, and as the product of social policies, laws, rules, and norms.
Take, for example, the social institution of education. The conscious and deliberate intention of the institution is to produce educated young people who understand their world and its history, and who have the knowledge and practical skills to be productive members of society. Similarly, the conscious and deliberate intention of the institution of media is to inform the public of important news and events so that they can play an active role in democracy.
Manifest Versus Latent Function
While manifest functions are consciously and deliberately intended to produce beneficial outcomes, latent functions are neither conscious nor deliberate, but also produce benefits. They are, in effect, unintended positive consequences.
Continuing with the examples given above, sociologists recognize that social institutions produce latent functions in addition to manifest functions. Latent functions of the institution of education include the formation of friendships among students who matriculate at the same school; the provision of entertainment and socializing opportunities via school dances, sporting events, and talent shows; and feeding poor students lunch (and breakfast, in some cases) when they would otherwise go hungry.
The first two in this list perform the latent function of fostering and reinforcing social ties, group identity, and a sense of belonging, which are very important aspects of a healthy and functional society. The third performs the latent function of redistributing resources in society to help alleviate the poverty experienced by many.
Dysfunction: When a Latent Function Does Harm
The thing about latent functions is that they often go unnoticed or uncredited, that is unless they produce negative outcomes. Merton classified harmful latent functions as dysfunctions because they cause disorder and conflict within society. However, he also recognized that dysfunctions can be manifest in nature. These occur when the negative consequences are in fact known in advance, and include, for example, the disruption of traffic and daily life by a large event like a street festival or a protest.
It's the former though, latent dysfunctions, that primarily concern sociologists. In fact, one could say that a significant portion of sociological research is focused on just that - how harmful social problems are unintentionally created by laws, policies, rules, and norms that are intended to do something else.
New York City's controversial Stop-and-Frisk policy is a classic example of a policy that is designed to do good but actually does harm. This policy allows police officers to stop, question, and search any person who they deem to be suspicious in any way. Following the terrorist attack on New York City in September 2001, police began to do the practice more and more, such that from 2002 to 2011 NYPD increased the practice by seven-fold.
Yet, the research data on the stops show that they did not achieve the manifest function of making the city safer because the vast majority of those stopped were found to be innocent of any wrongdoing. Rather, the policy resulted in the latent dysfunction of racist harassment, as the majority of those subjected to the practice were Black, Latino, and Hispanic boys. Stop-and-frisk also led to racial minorities feeling unwelcome in their own community and neighborhood, feeling unsafe and at-risk of harassment while going about their daily lives and fostered distrust in the police in general.
So far from producing a positive impact, stop-and-frisk resulted over the years in many latent dysfunctions. Fortunately, New York City has significantly scaled back its use of this practice because researchers and activists have brought these latent dysfunctions to light.