It has long been contended that one of the ways in which people make sense of their environment is by engaging in stereotypic thinking (Allport, 1954). In part, this process involves categorising others into groups on the basis of certain characteristics they may have (Fiske, 1998; Hilton & von Hippel, 1996). Once an individual has been categorised, characteristics and behaviours believed to be common to members of the social group are often automatically attributed to the individual (Bargh, 1994; Fiske, 1993; Macrae, Bodenhausen, Milne, Thorn & Castelli, 1997). The cluster of characteristics and behaviours that members of the group are believed to possess, comprises the stereotype of that particular social group (Hilton & von Hippel, 1996).
At present, there is considerable evidence to suggest that knowledge of the content of certain stereotypes, such as those concerning men and women, and significant racial groups, is widely shared within cultures (Augoustinos, Ahrens & Innes, 1994; Devine, 1989; Dovidio, Evans & Tyler, 1986; Haslam & Wilson, 1998; Krueger, 1996; Lepore & Brown, 1997; Stroupe & White, 1986). This type of awareness is referred to as knowledge of a stereotype (Devine, 1989). However, despite the fact that the features of a stereotype may be well known, it is only when the negative features are accepted or endorsed that the person is said to hold prejudiced attitudes toward these group members (Fiske, 1998). Moreover, it is widely believed that when prejudiced attitudes are held, discriminatory behaviour toward members of the stereotyped group results (Fiske, 1998). Thus, even though contemporary research into stereotypes focuses on the cognitive processes involved in stereotyping and on the types of attitudes that prevail, it is nevertheless argued to have important societal implications as stereotyping may ultimately lead to discrimination against others (Devine, 1989; Dovidio, Kawakami, Johnson, Johnson & Howard, 1997; Fiske, 1998; Stangor & Lange, 1994).
In reviewing stereotype research to date, it is apparent that while people may possess knowledge of and attitudes towards or explicit beliefs about a stereotype, there is a third way in which stereotypic information is thought to be processed (Devine, 1989; Dovidio et al., 1986; Banaji & Hardin, 1996; Bargh, 1994; Fiske, 1998; Hilton & von Hippel, 1996; Lepore & Brown, 1997; Locke, MacLeod & Walker 1994). This processing pertains to the subconscious or unconscious activation of stereotype-related knowledge, and, it is thought to occur when a member of or information about a stereotyped group is encountered (Allport, 1954; Dovidio et al., 1986; Hilton & von Hippel, 1996). When stereotypic knowledge is activated in this way, it is referred to as an automatic cognitive process, and the type of knowledge activated is termed implicit stereotypic knowledge (Devine, 1989). In expressing knowledge of and explicit beliefs about a stereotype, however, the cognitive processes said to be involved are controlled, owing to the fact that they are expressed at a conscious level (Devine, 1989).
Traditionally, explicit beliefs about stereotypes are measured through the use of attitudinal scales, wherein respondents are required to indicate the extent to which they agree or disagree with stereotype-related statements that are associated with the corresponding social category. Knowledge of a stereotype, on the other hand, is commonly measured using a free response scale, wherein respondents list features that they associate with the social category (Augoustinos et al., 1994; Devine, 1989; Lepore & Brown, 1997). This measure is usually employed to determine whether all respondents associate similar features with the stereotype (Lepore & Brown, 1997). While there seems to be a certain consensus as to adequate measures of knowledge of and explicit beliefs about a stereotype, there remains wide debate as to what constitutes an adequate measure of implicit stereotypic knowledge. The following discussion will explore research into stereotypic processes with a particular focus upon the techniques employed to measure implicit stereotypic knowledge.