Study on Phonological Loop Capacity and Digit Span Development in Spanish Population
This page outlines the aims, methodology, and key findings of a study conducted by Sebastian and Hernandez-Gil in 2012. The research focused on examining the capacity of the phonological loop and the development of digit span in the Spanish population.
Aims and Sample
The study aimed to investigate the phonological loop capacity in Spanish children and explore digit span development across age groups. It also sought to examine the effects of language differences and word length on digit span, as well as investigate potential age-related declines.
The sample consisted of 570 voluntary participants aged 5-17 years, all born in Spain and recruited from various schools. Additionally, 25 healthy older participants served as a control group, alongside 25 Alzheimer's patients and 9 frontotemporal dementia patients.
Highlight: The inclusion of both healthy participants and those with dementia allows for a comprehensive examination of digit span across different cognitive states.
Methodology
The researchers employed a digit span task to measure phonological loop capacity:
- Experimenters read out three sequences of digits at a rate of one per second.
- Participants listened and recalled the digits in the correct order.
- This process was repeated three times, with an additional digit added in each subsequent round.
- Digit span was determined as the maximum length at which participants correctly recalled at least 2 out of 3 series without errors.
Definition: Digit span refers to the number of digits a person can hold in their short-term memory and accurately recall in the correct order.
Results and Conclusions
The study revealed several important findings:
- Five-year-old children demonstrated a low digit span of 3.76.
- Spanish speakers generally showed lower digit spans compared to English studies, likely due to the word length effect.
- Elderly participants had higher digit spans than 5-year-olds but similar to other age groups.
- Frontotemporal dementia patients' digit spans were comparable to those of 5-6 year-olds.
- Alzheimer's patients' digit spans were higher than 5-year-olds but similar to other age groups.
Highlight: The study suggests that subvocal rehearsal, a key component of the phonological loop, is not fully developed until ages 7-8.
The researchers concluded that the capacity of the phonological loop is more affected by age than by dementias. They observed that digit span development across age groups shows an increase from childhood to adolescence, continuing to expand until at least age 17 in the Spanish population. The digit span growth appears to plateau around age 11.
Vocabulary: Subvocal rehearsal refers to the silent repetition of verbal information in one's mind to maintain it in short-term memory.
