The study followed a cross-sectional design that was approved by the Institutions Ethics Committee (Ethical Reference Number - IEC KMC MLR 11-18/463). The study was conducted between December 2018 and January 2020. The study was conducted within the classroom setting of the approached school. Written informed consent was procured from parents of children who agreed to take part in the study.

English medium schools affiliated to the Central Board of Secondary Education (CBSE), Mangalore city, were approached, after obtaining authorization from the Block Education officer, to recruit participants for the study. Those schools that provided permission to conduct the study were considered for data collection. Typically developing children who passed the WHO Ten-Question Disability Screening Checklist ( Singhi et al., 2007) were recruited for the study. Children with a history of any transfer from more than one school; a history of any shift in the medium of instruction; or a history of academic failures were excluded from the study.

A sample size of 80 was determined with respect to the study done by Appose & Karuppali (2018) using the formula: n = Zα ²σ ²/d ² where, Zα = 1.96 at 95% confidence level, d = 20% of the mean and, σ = standard deviation. The 80 participants were assigned equally into four groups (Group I: 6 years – 6 years 11 months; Group II: 7 years – 7 years 11 months; Group III: 8 years – 8 years 11 months; and Group IV: 9 years – 9 years 11 months ).

A story, “The Wooden Box” (copyright © 2019, Anil and Bhat), was constructed as animated stimuli and a “Word Recall” task ( Extended data ( Rooha et al., 2020)) was formulated based on the story to assess STM skills. The final modified task included 12 pictorially represented words that had an equal number of words from the story (Gold coins, Cupboard, Keys, Traffic), words thematically related (Hut, Chair, Diamond, Bag), and words unrelated to the story (Apple, Chair, Frock, Flower). Among the four words from the story, two of the words were presented in the auditory-visual modality (Gold coins, Cupboard), while the other two words were presented in auditory modality alone (Traffic, Keys). The task was to identify the pictures representing the words from the story. A score of one was given for each word recall.

The animated story as well as the formulated task was content validated by three speech-language pathologists and three primary school teachers of CBSE. The suggestions provided included using Indian names for the characters of the story, to modify the instructions and to modify certain words in the formulated task. These suggestions were incorporated in the preparation of the final stimuli.

Each child was evaluated individually in a classroom. The animated story was presented on a laptop screen, followed by the administration of the word recall task. The examiner presented the task verbally, and the child’s responses were scored simultaneously.

The responses were subjected to statistical analysis using SPSS software version 16.0 and significance was set at the 0.05 level (p<0.05). Descriptive statistics were used to obtain the mean and standard deviation of the data. A frequency measure was done to analyse the percentage of children recalling each of the words from each of the groups. One-way analysis of variance (ANOVA) test was used to test the difference in recall performance across the age groups. Further, the Bonferroni post-hoc test was done to assess the pair-wise differences in performance between the groups.

Younger children are fascinated by the illustrations of the story, and focus more on visual animations in comparison to the auditory narration of the story. Attention thereby forms a critical prerequisite to encode, store, and subsequently recall information. Reduced attention to auditory information may have contributed to poorer recall of words presented in the auditory modality. Hayes & Birnbaum (1980) observed similar behaviour and termed it as the “visual superiority effect,” i.e., younger children are more inclined to “look and not listen.”

Further, there exists a difference in processing the two types of sensory information. For the items to be stored in the STM, the brain has to cognitively create ‘mental images’ of these items, which are pictorial representations of words inside one’s mind. When processing visual stimuli, the brain functions to discover a ‘mental image,’ but when processing auditory stimuli, the brain has to create a mental image of the heard word for correct recall ( Hilton, 2001). These brain functions are mediated by higher cognitive skills, which develop only with age. This could have contributed to better recall of auditory-visual words when compared to auditory words.

This principle states that recall of memory is optimal when the retrieval conditions replicate the conditions present when memory was created ( Tulving & Thomson, 1973). In the current study, recall of auditory-visual memory was superior because the retrieval condition duplicated the conditions when the memory was formed, i.e. children had to identify the same pictures as seen in the story. However, the retrieval of auditory stimuli did not duplicate the conditions when the memory was formed, i.e. children had to identify pictures of words heard in the story, which could have contributed to poorer performance.

It is claimed that presenting multimedia information, i.e. presentations of material using words and pictures ( Mayer, 2002) results in deeper comprehension ( Boerma et al., 2016), subsequently improving recall. This can be considered as a contributing factor for better recall of auditory-visual words.

Lastly, Ferrara et al. (2017) reported that detailed visual memory capacity is present in children as young as six years of age, as a result of faster maturation of visual memory than the auditory memory. This can be considered as a contributing factor for observing no differences in auditory-visual recall performance across the age group.

These evidences supports the findings of the present study; an increase in STM skills with age, the existence of asynchrony in the auditory-visual and auditory recall scores, and recall performance strongly relating to the modality of presentation of information. These findings provide implications for the use of visual stimuli while teaching new vocabularies, skills, and concepts in younger children. These findings also highlight the use of visual stimuli while assessing speech, language, and cognitive skills in younger children as it will serve as a framework for maintaining their attention while evaluating various communicative skills.

Harvard Dataverse: Replication Data for: Short Term Memory abilities in Children, https://doi.org/10.7910/DVN/LLGPOX ( Rooha et al., 2020).

This project contains the following underlying data:

Harvard Dataverse: Replication Data for: Short Term Memory abilities in Children, https://doi.org/10.7910/DVN/LLGPOX ( Rooha et al., 2020).

This project contains the following extended data:

Data are available under the terms of the Creative Commons Zero "No rights reserved" data waiver (CC0 1.0 Public domain dedication).