Normal speed versus time-compressed speech in long-term memory retention: a randomized, within subjects experimental design

The COVID-19 has accelerated the educational shift towards different modalities and media types including online resources and video recordings. Students have sometimes used this opportunity to watch lecture recordings and posted material at faster playback speed. This function was also integrated in the daily use of social media like WhatsApp. The few existing studies show conflicting results when assessing its potential learning improvements and the effect of audio processing speed on cognitive load. As such, this study investigates the impact of time-compressed speech on long-term memory retention, one of the proxies for stable learning. The study aims to provide insight on the limited evidence pertaining to long-term memory recall in time compressed speech in episodic memory in early higher education learners. Based on previous studies, students are expected to recall less information when listening to time-compressed speech which would be reflected by lower cued recall scores. A total of forty university students were recruited. They were assessed using the Memory Assessment Scale and were counterbalanced on exposure to 23 s in times-compressed and a 23 s normal speed speech and a within subject comparison was made. In addition to demographics, the study also tracked the frequency of the subjects’ use of time-compressed speech in a learning environment as well as their attitude towards the benefits/downsides of using time-compressed speech. Our results show students had a higher-than-average tendency to use time-compressed speech and mostly noted its negative impact. Participants remembered around 50% of information accurately with a statistically significant difference between modalities: using normal speech led to an improvement of 27% for cued recall questions as compared to time-compressed speed. This data adds to the literature pointing to a gain in time offset by a loss in learning efficiency when students use time compressed material. Knowing these results can vary among individuals and learning materials, further studies could shed more lights on additional factors moderating the impact of time-compressed speech on cognitive performances or cognitive load.