The Implicit Relational Assessment Procedure (IRAP) is a measure of 'implicit cognition' developed on the basis of a contemporary behavioural analysis of language and cognition. The IRAP has now been applied to a range of foci over five years of published research. A frequently-cited caveat in publications to date is the need for further research to gauge the reliability and validity of the IRAP as an implicit measure. This review paper will provide a critical synthesis of available evidence for reliability and validity. The review applies a multifaceted test-theory approach to validity, and reliability is assessed through meta-analysis of published data. The discussion critically considers reviewed IRAP evidence with reference to the extant literature on alternative implicit measures, limitations of studies to date, and consideration of broader conceptual issues.Keywords: Implicit; Implicit Relational Assessment Procedure; Relational Frame Theory; validity; reliability Over the last two decades increasing attention has been given to the concept of 'implicit cognition' within psychological research (Greenwald et al., 2002). Although there remains a lack of consensus regarding the definition and operationalisation of this concept, reflecting broader differences in the theoretical and epistemological orientation of researchers in this area, a number of measures of 'implicit cognition' have been developed. The most commonly used and extensively discussed of these measures is the Implicit Association Test (Greenwald, McGhee, & Schwartz, 1998). The IAT was designed to measure the relative strength of pairs of associations (e.g., insects-disgust vs. flowers-disgust) in a computerised categorisation task. As an example, relatively rapid responding to insects-disgust (in comparison with flowers-disgust) would be considered indicative that insects and disgust are more strongly associated in memory.Much of the evidence-base for implicit cognition has been developed through applications of the IAT and this measure has formed a prototype for subsequent developments in implicit measurement (Nosek, Hawkins, & Frazier, 2011). Most implicit measures have thus been designed to target a basic association between stimulus-pairs under conditions of time pressure. This operationalisation promotes the assumption that implicit cognition reflects the activation of an underlying associative-memory network -an assumption that is evinced in the representational models outlined by key researchers in the cognitively-aligned fields. However, it is important to distinguish the associative procedures of implicit measures from inferences about underlying processes or representations (Hughes, Barnes-Holmes, & De Houwer, 2010).
The Implicit Relational Assessment ProcedureThe Implicit Relational Assessment Procedure (IRAP; Barnes-Holmes et al., 2006) represents an alternative measure of implicit responding, developed from the perspective of From an RFT perspective it is not the extent to which two stimuli are 'associated in memory' that is...