Credibility of messages, studied in the communication, psychology, sociology, political science, and other literatures, is generally defined as a collection of attributes of messages that make the message content or their senders valued relative to the information imparted. The attributes generally refer to either the sources of the messages’ content or the authenticity of their meaning. Perceived source or message credibility, then, is generally defined as a message recipient’s recognition and holding of evaluative information about these messages and their sources.
Credibility Mostly Conceptualized As Source Credibility
Perhaps the most noticeable characteristic of information credibility is its source – the individual who reported it, wrote it, or was quoted in messages. This human voice of messages is one of the most studied concepts in communication research. In addition, the institutions associated with the human sources, whether government agencies, private, or not-for-profit, have been found critical in determining credibility, as have the media organizations that bring the information to the message receivers – mass media news, advertising, entertainment, and sports, in particular (Berlo et al. 1969; Singletary 1976). Historically, credibility has been researched almost exclusively in persuasion, which generally studies whether messages or speakers can change people’s beliefs, attitudes, and behavior. Stemming from the classical Greek focus on credibility, typically the work of Aristotle and Plato, the study of “ethos” has distinguished the field of public speaking in examining properties of texts and judgments of audience members about characteristics of speakers during rhetorical transactions. It was well into the twentieth century before communication social scientists began a systematic look at communication, and, therefore, credibility (Hovland & Weiss 1951). Although it was one of the first communication concepts studied, credibility remains an area with many questions.
Credibility has been studied empirically relative to human social behavior as a characteristic of speakers, organizations, media (usually news media), messages, or communication contexts. Early research investigated the relative trustworthiness of different media presenting similar information. Research specific to rating news media sources has investigated publications, not individual communicators (Gaziano & McGrath 1986). Early on, this work found newspapers to be the most trusted purveyors of news. Interestingly, a new medium, radio, followed with an era when the first electronic media form became more trusted than newspapers. Later, with the innovation of television, news on that medium became the top trusted source (Lee 1978). Some recent work has examined new information technology in this regard.
Most of this work has used audience perceptions of credibility, not systematic inquiry into what specific attributes about these particular media were believed to garner their comparatively greater trust. Some interpretation of this literature has proposed that the more personal delivery of electronic media has made it more trusted than mere printed information, i.e., the friendly voice or face of the newscaster bringing the news to the home in a recognized, personable, consistent style. This area of research has extended beyond issues of trust to such matters as a media institution’s social concerns and level of patriotism (Gaziano & McGrath 1986).
The conceptual definition of source credibility stems from some of the earliest social science research in communication and mass communication, where message characteristics were examined as they impact persuasion. The first published empirical work on credibility as it pertains to persuasion presented information in experimental settings to message recipients about a source who was either an expert on a topic or who was trusted by audience members. Often these earlier researchers mixed the people, messages, and communication channels to represent credibility. For example, in the 1950s, pioneer researchers Carl I. Hovland and Walter Weiss (1951) presented audience members with information from the following sources, thought to indicate a high level of trustworthiness: Robert S. Oppenheimer, the scientist who led the development of the hydrogen bomb, writing about the practicality of atomic submarines; Fortune Magazine; the Bulletin of the National Resources Planning Board; and the New England Journal of Biology and Medicine. These scholars used the following low-credibility counterparts: Pravda, the Soviet Union’s state newspaper; an “anti-labor, anti-New Deal, ‘rightist’ newspaper columnist”; “a monthly pictorial magazine”; and a syndicated women’s movie gossip columnist. Research that followed frequently focused solely on audience judgments about people sources or institutional sources. Other confounding aspects of sources, such as gender, notoriety, and political ideology have also been teased out.
Dimensions And Measurement Of Source Credibility
Over time, findings of source credibility that utilized similar measures to the early research distinguished two consistent dimensions of the concept: (1) expertise is the extent to which a communicator is perceived by audience members as providing correct assertions, and (2) trustworthiness is the extent to which the audience members perceive that the assertions made by a communicator or speaker are assertions that the communicator considers valid (Sternthal et al. 1978). Expertise, then, generally involves a communicator’s knowledge, accuracy, and precision relative to the subject matter presented in messages. Trustworthiness, on the other hand, can be thought of as the source’s intentions in the relationship between the message and the receiver of the message. For example, a source is perceived as honest, believable, sincere, and reliable by message recipients. A shift in studying source credibility as merely an attribute of a message to the perceived credibility by audiences paralleled a paradigmatic shift in mass communication research, which at the time first viewed media content as all-powerful and important, capable of massive, uniform effects on audiences – moving to the view that aspects of audiences were also important, and that sometimes audiences could resist media influence. This eventually gave way to the view that audience transactions with media messages depended on various personal and contextual factors – audience characteristics like selectivity, motivation, and decision-making.
Hundreds of scale items have been used to measure source credibility, and this concept has been studied as both an independent cause of persuasion, a contributory factor in a persuasion situation, and as the result of persuasion (Singletary 1976). Typical indicators of credibility, besides “credible” and “trustworthy,” are “believable,” “expert,” “dynamic,” “helpful,” “rational,” “objective,” “professional,” “intelligent,” and “qualified.” Although researchers have developed multidimensionality to source credibility, this has generated greater complexity of the concept rather than greater insight into its meaning (McCroskey 1966). Such components as dynamism, attractiveness, and professionalism have enhanced scientific understanding of how the style or presentation of a communicator is part of that communicator’s credibility, or the associated audience’s perception of credibility. There has been some controversy about using traits of individuals as dominant in the study of perceived source credibility by audiences (Delia 1976). Over time, many studies have found that expertise and trust remain as useful dimensions for this concept.
Source Credibility As A Peripheral Aspect In Research
Regarding the importance of credibility in communication research, the phenomenon has taken a back seat to other critical aspects of persuasive messages. This was evident even in the first studies by Hovland and his colleagues, who initially may have been more interested in the propagandistic nature and sidedness of messages than the credibility of the message sender (Hovland & Weiss 1951). They found an initial difference for high and low credibility conditions, in that people who received information from the high credibility sources, compared to the low credibility sources, were more persuaded. However, they found a delayed sleeper effect about four weeks later, where the credibility of the sources were believed to be disassociated from the messages, and persuasive information from both types of sources was retained by experimental participants.
Even in recent persuasion research – indeed, in most current state-of-the-art persuasion models, like the elaboration likelihood model in cognitive response theory (Petty & Cacioppo 1986) – source credibility is considered a peripheral cue to message processing. Although this research emphasizes message content characteristics that guide the cognitive processing of message content, understanding the actual processing mechanisms involved relative to message credibility remains elusive. In this theoretical approach audience members are thought to process central message content when they are highly motivated or involved in the message or its outcome. Conversely, audience members who are low in motivation or involvement are thought to pay attention to peripheral, less important message cues, such as source credibility.
This research brings to question the subject of the credibility of the message itself, as a message might also be viewed by audience members in persuasion or learning contexts as more or less credible. To a lesser extent, message credibility has been studied, particularly in experimental research (Slater & Rouner 1997). As far as message characteristics are concerned, qualities such as strong vs weak evidence, narrative vs statistical content, truthfulness, number of arguments and variety of arguments have been studied. Some of this research shows a message credibility impact on source credibility, or an enhanced persuasive effect when credibility of the message and source were taken into account as to their combined effect on attitude change or behavior.
Some research documents situational circumstances or audience states that moderate the impact of credibility cues on either persuasion or learning. These include involvement or personal stake in a message’s topic, knowledge and direct experience, and dispositional factors like incredulity and cognitive complexity. Only a few research studies have investigated the actual nature of processing strategies associated with message and source credibility. Recent work not only continues to investigate persuasion processes but has expanded this inquiry to the study of information processing of information not meant for persuasion, such as news and public affairs media, as well as entertainment messages. Accurate reflection of social reality, believability, and message quality assessment are some more recent audience determinations that might affect source credibility.
Resurgence Of Credibility Research
Recently, two research areas in the study of media have yielded a resurgence of credibility research: new information technology and health communication. Scholars have been studying message features of new information technology, for example, world wide web structural elements and message content quality, like thoroughness, complexity, and truthfulness. Combining this technology focus with health communication has become important, given the increasing use of new information technologies for health information in prevention, identification, diagnosis, treatment, and possible cures for varied health matters. Credibility of messages and their sources takes on new meaning for individuals recently diagnosed with cancer, possibly seeking more information about their illness and prognosis, available health information about future prospects, and a virtual community of cancer survivors with whom they might learn ways to cope and to share their stories.
Some additional audience characteristics found related to credibility include gender, race, ethnic similarity to the audience member, management style, and leadership. Gender differences have been mixed, demonstrating both research that shows males more credible than females and females more credible than males. However, recent research has found less evidence of gender differences, suggesting a time-period phenomenon that may have led to less bias against females as information sources, compared to the past, when males dominated as speakers and news deliverers.
The robust concept of credibility has held strong across the many years since communication originated as a field of study. It continues to be a crucial component of media content, particularly in public affairs, public speaking, politics, advertising, marketing, and public relations.
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