In short-term trials, Uncapher et al. separated 139 Stanford students into two groups: light media multitaskers (LMMs) or heavy media multitaskers (HMMs). After showing the participants images of target objects surrounded by distractors, the researchers found a statistically significant correlation between intensity of media multitasking and weakened short- term memory retention. Next, they questioned multitasking effects for long-term memory recall. In the same groups, students were shown only target objects and asked if these objects were the ones shown in the short-term trials. Their ability to correctly identify any change was defined as the discriminability parameter (d’). Researchers found that HMMs had lower d’ scores, indicating their brains were less capable of precisely recalling stored information.
The figure depicts long-term memory recall performance of LMMs and HMMs. Across the four trials, HMMs often answered incorrectly, resulting in scores approximately 0.2 less than LMMs in all four trials. HHMs more likely saw no change when one occurred, or vice versa, because their brains recalled information less accurately. The results show that multitasking weakens cognitive abilities to retrieve information. However, HHMs might argued that there is a sharper decline in LMM scores between the zero and two distractor trials, indicating LMMs may have diminished long-term memory capabilities as well. However, when the number of distractors increased to four, HMMs scored 0.3 lower than LMMs and there is no overlap in error bars. Therefore, reduced difference cannot be attributed solely to the increase in distractors. Furthermore, the p value of 0.0023 indicates a statistically significant difference between LMM and HMM scores because the difference can only be attributed to chance 0.23% of the time.
The consistently lower scores of HMMs illustrates that they recalled stored information with less precision. Choosing to multitask increases the likelihood of impairing cognitive pathways responsible for information retrieval. College students, in particular, must be forewarned of these consequences and reminded to focus on one task at a time for the sake of their learning and test scores.
* Uncapher, Melina R et al., Psychonomic Bulletin & Review Vol. 23.2 (2016)