Premack and Woodruff (1978) have proposed the term of Mind (ToM) to refer to one's ability to infer the beliefs, intentions and thoughts of others in order to explain and predict their behavior. Understanding how ToM operates has been the subject of debate for more than twenty years in cognitive psychology, but has only recently been studied in behavior analysis. Although the concepts of ToM do not lend themselves readily to a functional interpretation, some behavioral researchers working under the rubric of Relational Frame Theory (RFT) have attempted to develop a behavioral interpretation of the types of repertoires that constitute a ToM (McHugh, Barnes-Holmes, & Barnes-Holmes, 2004a). Relational Frame Theory is a modern behavioranalytic approach to the study of human language and cognition. At its core, this approach embraces the simple idea that language and cognition involve a number of limited but powerful behavioral processes, that allow individuals to relate stimuli or events in the world in new and untrained ways (as in generative language). A range of behavioral patterns emerge as a result of these relations between stimuli and these patterns are referred to as relational frames (see Hayes, Barnes-Holmes, & Roche, 2001). The simplest form of such relating can be referred to as coordination framing. An example of this type of framing might go as follows: a child could learn that the written word DOG is the same as the spoken word DOG according to the non-physical characteristics of these two stimuli while their physical form is very different. According to RFT, it is the uniquely human ability to learn to relate objects and events not based on their physical form but on external cues that allows for the generativity of human language. Among the different ways in which two stimuli can be related, Barnes-Holmes, Hayes, and Dymond (2001; see also Barnes-Holmes, McHugh, & Barnes-Holmes, 2004) have underlined the role of a specific class of relational responding termed deictic framing, which is assumed to underpin perspective-taking and, thus to be critically important with respect to the ability to infer the mental states of others. The three deictic frames involved in the acquisition of perspective-taking skills are the frames of I and YOU, HERE and THERE, and NOW and THEN, corresponding to interpersonal, spatial, and temporal dimensions, respectively. According to this view, perspective-taking skills emerge through a history of responding to questions such as > or >. Many phrases during daily discourse include these relational frames, even if substituted words such as the names of places, people and time are frequently used instead of the actual terms of I and YOU, HERE and THERE and NOW and THEN. Following the RFT approach to ToM, McHugh et al. (2004a) have proposed an RFT interpretation of the developmental levels of ToM described by Howlin, Baron-Cohen, and Hadwin (1999). That is, the authors suggested that levels from simple visual perspective-taking to the understanding of false-beliefs involve the ability to respond in accordance with deictic relational frames. Consider the following example of a well known false-belief task (Gopnick & Astington, 1988), in which a participant is asked what is inside a closed candy box. After responding, the candy box is opened and the participant discovers that the candy box did not contain candy but actually contained pencils. Then s/he is asked >. The RFT view of this task is that a correct response coming from the participant is underpinned by relational frames as follows: >. In order to study this interpretation, McHugh et al. …