Factor analysis of working memory tasks based on information processing characteristics: Predictive factors of receptive vocabulary and quick incidental learning in children with typically developing and receptive vocabulary delay

Objectives: The purpose of this study was to classify working memory tasks into several categories and to find the coherent and predictable factors of children's receptive vocabulary and Quick Incidental Learning (QUIL). Methods: A total of 56 children (24 children with Receptive Vocabulary Delay [RVD] and 32 children aged 4 to 8 with Normal Language [NL]) participated in the study. Their language skills and working memory capacity were measured through the Receptive Vocabulary Test (REVT-R), QUIL, the Working Memory Tasks (WMT)-varying in modality (visual vs. auditory) and stimulus types (numbers, colors, shapes, and words)-Nonword Repetition, the Compete Language Processing Task (CLPT), and Matrix. Exploratory factor analysis and stepwise regression were used in data analysis. Results: In NL group, 11 WMTs were classified into two factors: Simple WMT (SWMT) and Complex WMT (CWMT, i.e., Dual-processing WMT [DWMT] + Multi-processing WMT [MWMT]). However, in RVD group, WMTs were classified into three factors: SWMT, DWMT, and MWMT. SWMT and CWMT were the strongest predictors of receptive vocabulary for the NL group, whereas SWMT and DWMT were the strongest predictors for the RVD group. In addition, CWMT was the best predictor of QUIL for the NL group, whereas no predictor of QUIL was found for the RVD group. Conclusion: All of the 11 WMTs were classified into several factors depending on domain, modality and information processing load. These results indicate that it is important to pay attention to integrated cognitive measures for working memory in visual and auditory modalities, and linguistic and non-linguistic stimulus types.