以刺激等同為基礎之教學──智能障礙學生功能性詞彙對稱與轉移之表現成效

Effects of equivalence-based instruction on the emergence of symmetry and transitivity in the Chinese functional vocabulary of two students with intellectual disabilities in Taiwan

本研究旨在探討以刺激等同為基礎之教學對智能障礙學生功能性詞彙對稱與轉移之表現成效。本研究以中部地區兩名國小智能障礙中度學生為研究對象。研究方式採單一受試跨行為多試探實驗設計。自變項為以刺激等同為基礎之教學，刺激組分別是為字卡（A）、圖卡（B）、口說（C），學習材料為功能性詞彙，依類別分為三個主題（食物類、餐具類、衣物類）。依變項之一為直接接受教學功能性詞彙之刺激－刺激關聯組（A-B）的習得百分比，依變項之二為接受教學刺激組（A-B）後所自動衍生之「對稱」（B-A）表現，結合原本具備的B-C關聯，能衍生產生「轉移」（A-B，且B-C，則A-C，C-A）表現。研究結果以視覺分析進行資料分析，最後邀請家長與教師填寫問卷並訪談家長以建立社會效度。研究結果摘要如下：一、在接受教學後，兩名受試者在三個主題功能性詞彙中之「字卡-圖卡」（A-B）關聯之習得百分比具有立即與材料類化成效。二、兩名受試者已具備「圖卡－口說」（B-C）關聯能力，結合新習得的（A-B）關聯，經探測結果顯示，對未經教學的刺激－刺激關聯能衍生對稱（若A-B，則B-A）表現、與轉移（若A-B且B-C，則A-C，C-A）成效。三、家長與教師均肯定以刺激等同為基礎之教學對功能性詞彙之學習成效。本研究亦針對研究結果提出相關議題之討論並對實務教學及後續研究方向提出建議。

Rationale and Purpose: Teaching functional vocabulary is a key method for facilitating adaptations to everyday life for students with intellectual disabilities. Equivalence-based instruction (EBI) involves incorporating principles of stimulus equivalence into instructional design to teach various academic skills and concepts. Behavior analysts define stimulus equivalence by investigating reflexivity (A=A), symmetry (if A=B then B=A), and transitivity (if A=B and B=C, then A=C) in stimulus-stimulus relations. For the teaching of A-B and B-C relations, the automatic development of A-C and C-A relations without direct teaching, and stimulus equivalence can be attributed to the rapid language acquisition that young children undergo. The purpose of this study was to investigate the effects of EBI on the symmetry and transitivity of the Chinese vocabulary for students with intellectual disabilities. This study examined whether providing training in A-B relation to children with knowledge of B-C relation at pre-intervention leads to the development of knowledge regarding the untaught relation pertaining to symmetry (B-A), and transitivity (A-C and C-A). Methods: The participants were two elementary students with intellectual disabilities. Participant 1 was a second-grade female student, and participant 2 was a second-grade male student. Both were enrolled in a self-contained special education classroom. The Repertoire of participant 1 included: can follow 2-step directions, mand with words, tact more than 20 objects and possess a few intra-verbal behaviors. The repertoire of participant 2 included: can follow 2-step directions, mand with words, tact more than 30 objects and possess a few intra-verbal behaviors. Before the intervention was implemented, the researchers designed a functional words assessment questionnaires that comprised three categories (i.e., food, tableware and clothes) to determine the target words used for the intervention. A single-subject experimental design of multiple probes across behaviors was applied in this study. The independent variable was the stimulus-equivalence based training, and the dependent variables were the improvements of functional vocabulary of one stimulated classes out of six, at the completion of the intervention program, and through other stimulus classes that applied stimulus-equivalence. The three types of stimuli used in this study were (A) texts, (B) pictures, and (C) utterances of object names. The participants had acquired the ability to tact pictures (B-C) prior to the intervention. The research procedure is as follows: (1) The pretest phase involved: conducting the Chinese vocabulary assessment before intervention; (2) the baseline phase: gathering A-B relation data for establishing baseline logic; (3) the intervention phase involved: teaching A-B relation, applying a mastery criterion (i.e., correct response rate of 80% for three consecutive sessions), and conducting 25-minute teaching sessions twice a week; (4) the probe phase (posttest) involved: the probing of B-A、A-C, C-A relations (i.e., untaught relations pertaining to symmetry and transitivity) to verify if the participants acquired the knowledge of them. Subsequently, generalization probe and maintenance steps were performed. A visual analysis was used to assess the learning effectiveness. A trial-by-trial inter-observer agreement was conducted to ensure the quality of the dependent variables. The data collected at during the baseline (2 data), intervention (7 data), generalization (1 data) and maintenance (1 data), phases exhibited a mean of 97.75%. Procedure fidelity was tested, and a mean score of 95% was obtained. Through the questionnaires and interviews with the participants' parents and teachers, the social validity of the study was verified. Results/Findings: The results of the study are as follows: (1) The equivalence-based teaching intervention had immediate and generalized effects on the correct response rates pertaining to functional vocabulary learning (A-B). (2) After the equivalence relations between words and their corresponding images (A-B) were taught to the participants, they acquired the knowledge of corresponding - symmetrical (B-A) and transitive relations (A-C and C-A) without direct training. (3) For social validity, the caregivers and teachers of the participants reported favorable outcomes. Conclusions/Implications: (1) The results indicate that the participants developed the ability to accurately respond to untrained and non-reinforced stimulus-stimulus relations (i.e., symmetry and transitivity) following the reinforcement of their responses to A-B stimulus-stimulus relations in Chinese vocabulary. These findings are similar to those reported by Sidman and Taiby. (2) Trials-to-criterion data are useful for assessing the improvements in a learner's competence (after they learn relevant set of concepts) and for evaluating the efficiency of a teaching procedure. Participant 1 exhibited a trials-to-criterion decrease across target behaviors, which can be attributed to her increasing competence in stimulus-equivalence learning procedure, and the effects of EBI on her understanding of Chinese vocabulary symmetry and transitivity. These findings correspond to those of Elias et al. (3) The present study also revealed the stimulus generalization effects of the intervention. Various teaching materials for achieving stimulus generalization were prepared, this steps especially relevant for the Chinese language because Chinese text can be written vertically or horizontally, and the step help both the participants to master the target behaviors and apply them in a practical setting. (4) The observation data collected by the researcher and from the parents revealed that the two participants not only exhibited improvements in the target behaviors but also generating to the untargeted behaviors. According the parents', the generalization effects also included an increased ability to recognize written words, increased motivation to write words, and increased competence with respect to everyday life activities (e.g., willingness to speak and ability to name things). (5) Future studies should expand their samples to include participants of different ages and participants of different disabilities; colorful training stimuli or computer assist technology, test other modalities (e.g., text, olfactory and taste) and use target words selecting from advanced vocabularies. (6) Recommendations for practitioners: EBI has been proven to be an efficient teaching method on the emergence of symmetry and transitivity by reinforcing responses to A-B stimulus-stimulus relations pertaining to Chinese vocabulary. A token economy was used in this study to enhance learning motivation, and this system can be incorporated into teaching. The use of functional words that matched the preferences of the students can increase their learning efficiency and generating to other unknown words.