Developmental changes in directing attention within visual short-term memory: The role of long-term representations

Abstract

Visual Short-term memory (VSTM) is one of the most crucial processes involved in many cognitive tasks. It is well-established that VSTM in adults can support a limited amount of information. However, this amount can be increased with the help of visuo-spatial attentional cues. In an earlier study, Shimi et al (2014) found that not only adults’ but also children’s VSTM benefited from attentional cues, however, children benefited from these cues to a smaller degree compared to adults, indicating children’s difficulties in orienting attention during the maintenance of information in VSTM. In addition, research showed that adults’ VSTM is higher when participants need to retain familiar items than unfamiliar (Cowan et al., 2015; Ricker & Cowan, 2010). Shimi and Scerif (2015) also found that the familiarity of the item can enhance VSTM in adults and showed further that familiarity can also enhance VSTM in children, yet to a smaller degree, suggesting possible developmental differences in how long-term memory (LTM) may facilitate VSTM. Importantly, they demonstrated that VSTM maintenance is better for cued familiar items for both children and adults, yet children benefitted less from attention cues compared with older individuals, indicating that attentional benefits interact with memoranda familiarity differently across development. Put together, these previous findings suggested that both attentional control and LTM may constrain children’s VSTM compared with older individuals. Therefore, our goal here was to examine further the developmental changes in directing attention within VSTM and the exact role long-term representations may play in these developmental improvements. To investigate this further, we trained 7-year-olds, 11-year-olds, and young adults to associate unfamiliar items (i.e., meaningless shapes) with familiar items (i.e., animals) in order to learn and store new mental representations in LTM. Then, we examined the impact of these newly-formed LTM representations on attentional orienting in service of VSTM performance across different age groups and in comparison with control groups. Results showed that all participants’ VSTM benefitted from attentional cues, however, benefits were smaller for children than for adults. In addition, item familiarity facilitated participants’ performance and cue benefits were larger for familiar than unfamiliar items. Performance was also affected by age, as adults performed better than children. Finally, while adults in the training group performed better than adults in the control group, children’s performance in the two experimental groups did not differ. These age group differences may indicate potential differences in how children use LTM representations to facilitate VSTM. Overall, data from the current thesis are in agreement with previous research in the field that suggests that memoranda characteristics, top-down biases, and storage capacity contribute to developmental differences in VSTM.