PRELIMINARY FINDINGS ON THE EFFECTS OF SELF-REFERRING AND EVALUATIVE STIMULI ON STIMULUS EQUIVALENCE CLASS FORMATION

Thirty-two subdues completed 2 stimulus equivalence tasks using a matching-to-sample paradigm. individual task involved direct reinforcement of conditional discriminations designed to show derived relations between self-referring stimuli (eg me myself, I) and positive evaluation words (eg whole, desirable, perfect) The other task was designed to bring forward derived relations between self-referring stimuli and negative evaluation words (eg unworthy, flawed, inadequate). Performance upon each task was recorded via replication latency and percent correct. Prior to completion of the equivalence tasks, bring under rules completed 2 self-report measures: the consequence Questionnaire-45 (OQ-45) and the Rosenberg self-complacency Scale (RSE). Subjects were divided into assemblages based on their OQ-45 score (high or depressed distress) and RSE score (high or depressed self-esteem). Significant differences in percent correct were fix between both the OQ-45 assemblages and the RSE groups. make submissives who reported high distress and a negative faculty of perception of self made significantly more errors upon the tests for equivalence for the task that required matching self-referential stimuli with positive evaluation words.

Stimulus Equivalence

Murray Sidman leadershiped the first systematic investigation of stimulus equivalence in 1971 In this well-cited close attention an individual with a learning disability was taught to identify pictures of things given the spoken words. He was then taught to identify the written words given the nuncupative words. Without any additional training, the individual matched the pictures to the written words and the written words to the pictures. That is, he derived relations among the stimuli in the absence of direct reinforcement for the specific choices, responding to the stimuli as if they were equivalent. Sidman referr to this behavioral phenomenon as stimulus equivalence and identified reply features that indicated that a stimulus equivalence class had been formed (i.e., reflexivity, harmony and transitivity) (Sidman, 1990). following studies have supported Sidman's observations of stimulus equivalence. Specifically, studies have repeatedly demonstrated that when an individual is taught a series of related conditional discriminations (eg single out A^sub 1^ in the nearness of B^sub 1^, choose A^sub 1^ in the neighborhood of C^sub 1^), he/she oftentimes derives additional relations that were not explicitly taught (eg choosing B^sub 1^ in the vicinity of C^sub 1^ and C^sub 1^ in the nearness of B^sub 1^). Research has demonstrated that children as young as 17 month engage in simple relating and through 23 months they demonstrate all the necessary answer features of stimulus equivalence (Lipkens, Hayes, & Hayes, 1993)

Investigations of stimulus equivalence have focused primarily upon identifying the conditions that reliably bring forward equivalence (Sidman, 1990; Sidman & Tailby, 1982) and examining central features of stimulus equivalence classes. This research has demonstrated resurgence of previously established equivalence relations (Wilson & Hayes, 1996) transfer of a variety of psychological functions among class members (Dougher, Augustson, Markham, Greenway, & Wulfert 1994; Dymond & Barnes, 1994; Roche & Barnes, 1997) differences in acquisition between language-able and language disabled populations (Devany, Hayes, & Nelson 1986) that equivalence classes can include stimuli of various modalities (DeGrandpre, Bickel, & Higgins, 1992) and that classes can be brought below contextual control (Kohlenberg, Hayes, & Hayes, 1991; Steele & Hayes, 1991) Among novel studies, derived relations other than equivalence have also been reliably demonstrated (Dymond & Barnes, 1995: Steele & Hayes, 1991)

Inclusion of Meaningful Stimuli

Most investigations of stimulus equivalence have used arbitrary stimuli. However, more [i]or[/i] less investigators have turned their attention to the impact of stimuli that are emotionally salient, clinically relevant, or socially loaded upon equivalence class formation (e.g., Barnes, Lawlor, Smeet & Roche, 1996; Leslie, Tierney, Robinson, Keenan, Watt, & Barnes,1993; Moxon Keenan, & Hine, 1993) In general, this research indicates that the inclusion of "meaningful" stimuli delays or inhibits the formation of stimulus equivalence classes (eg Plaud, 1998) and that this event appears to result from subjects' specific preexperimental learning histories. For example, Leslie et al. (1993) compared the performance of clinically anxious controls to the performance of nonanxious make submissives on a stimulus equivalence task. Conditional discrimination training was provided, using a matching-to-sample operation which should result in the subdues deriving a relation between pleasant state adjectives (eg "relaxed") and anxiety provoking situations (eg "public speaking"). proceeds indicated that 7 of the 8 clinically anxious bring under rules were unable to form the equivalence classes, compared to alone 2 of the 8 nonanxious bring under rules A similar study by Plaud (1995) reported that the acquisition of equivalence relations was delayed when the classes contained fearful (i.e., snake related) stimuli compared to those that contained nonfearful (i.e., flower) stimuli. Plaud (1995) also base that a subject's performance was predictable given his/her verbal report of fear of snakes.