Visual Short-Term Memory Studies and Results Yield Potential for Additional Research and New Applications

The visual system is one of the many networks that has been rigorously studied and continues to yield more questions at the same, if not faster, rate as it yields answers. The visual system is a highly complex system that overlaps with other cognitive processes such as memory. Matsukura and Hollingworth as well as Vissers et al have performed research into this particular intersection known as the visual short-term memory (VSTM). Both research teams looked at the VSTM maintenance that yielded findings particularly relevant to one another and holds potential for additional research. 

Michi Matsukura and Andrew Hollingworth conducted a series of experiments that tested whether visual short-term memory (VSTM) had a high-capacity stage. This research was prompted by recent results from work done by Sligte et al. that suggested the existence of a high-capacity VSTM retention stage. Matsukura and Hollingworth conducted four experiments to test the strength of Sligte et al.’s results against the long-standing belief of VSTM limited-capacity system. Experiments 1a-1b replicated Sligte et al.’s Experiment 3 experimental methods with modifications that exempted a  3-hour practice session and the ability for participants to repeat blocks of trials. Experiments 2-3 followed similar methods with the exception that Experiment 2 reduced the possible orientation outcomes to two and Experiment 3 included a color memory component to extend the testing of VSTM. The results of Experiments 1a-1b and experiments 2-3 showed that change-detection accuracy was higher for valid cues rather than neutral cued trials. The cuing effect and introduction of color discrimination significantly affected overall accuracy. With these results however, there was no indication of a separate and qualitatively different VSTM that was outside of the traditional limited-capacity VSTM. Matsukura and Hollingworth conducted a fourth experiment to find the cause of Sligte et al.’s results of high performance of change-detection. Experiment 4 maintained that no redoing of block trials occurred. The results of Experiment 4 concluded that change-detection accuracy improved with practice. Overall, despite the results of Experiment 4, Matsukura and Hollingworth maintain that “no compelling” evidence of a high-capacity VSTM exists and suggests that improved performance after practice in change-detection does not directly suggest an increase in capacity. Conversely, the study done by Vissers et al used the belief of VSTM high and low capacity varied by individual to examine processing levels in the VSTM. 

In Vissers et al Protecting visual short-term memory during maintenance: Attentional modulation of target and distractor representations they examined the role of attention in processing various levels of relevant visuospatial information during VSTM encoding and maintenance. They set their focus on attentional filtering during VSTM with reliance on local modulations in sensory regions. Vissers et al cites studies that have reported patterns on attentional selection in regards to the VSTM. These studies report that suppression of distracting information is more efficient in individuals with high VSTM capacity. Evidence is provided through the studies of attentional filtering during VSTM encoding during modulation with task-irrelevant information. However, due to the loose results Vissers et al state that it is still unclear if VSTM performance relies on selective suppression of sensory information and its ability to differentiate relevance and irrelevance. This leads to questioning if the attention factors encoded are still actively aiding in VSTM maintenance and post perceptual stages. To test this, 37 participants completed complex working-memory tasks and were examined using EEG data. Visser et al found that their data was consistent with their prediction that VSTM performance held a correlation between a high or low distractor load condition. The main findings that Visser et al reported was that individual differences factored into distractor load; attention strongly modulated SSVEP response; and cross-subject analyses revealed a relationship between the deployment of spatial attention to target vs distractor locations and distractor load effect. The findings collectively support the notion that sensory representation quality during VSTM encoding may preserve sensory representation during VSTM maintenance. 

The work of these two research teams found differential results in regards to VSTM capacity. Due to the separate nature of their respective research questions I come to believe that a new study that replicates Matsukura et al experiments with a new research question could be used in unison to further investigate the VSTM capacity. Using the data of both research teams and formulation of a research question that looks at the isolation of effect of singular vs multi stimuli can yield additional evidence in researching VSTM capacity whether that be in favor or against the original studies. I believe that the studies can be used not only to formulate or come closer to a conclusion for this topic but can also be implemented into learning techniques and teaching styles. Given the rapidly changing and progressive nature of online learning, not only in the wake of COVID-19 but, in the age of technology and increasing availability for higher education through a web space or the use of web space in classes, this data can guide educators in providing more focused lesson tasks with research into VSTM maintenance and capacity ability. 

   

References

Matsukura, M., & Hollingworth, A. (2011). Does visual short-term memory have a 

high-capacity stage? Psychonomic Bulletin & Review, 18(6), 1098–1104. 

https://doi.org/10.3758/s13423-011-0153-2

Vissers, M.E., Gulbinaite, R., van den Bos, T. et al. Protecting visual short-term 

memory during maintenance: Attentional modulation of target and distractor 

representations. Sci Rep 7, 4061 (2017).

https://doi.org/10.1038/s41598-017-03995-0