Humans are constantly learning new information whether it be from school or just day-to-day life. Even before leaving the house in the morning, many will consume information on the time, the weather, traffic reports, recent news and other daily details. Between the constant exposure to new information and the conscious efforts many individuals make to pursue education, the brain is tasked with holding an amplitude of information. Given each of the brain synapses can hold 1 bit of information, the human brain capacity is approximated to measure 100 terabytes of information (Moore, 2014). To put that into context, the maximum storage the most recent iPhone can hold is 1 terabyte (Anon., 2024). However, even with this immense processing power the human brain faces three key limitations which can inhibit our ability to perceive and consume information. This includes the attentional blink (AB), the psychological refractory period (PRP), and the visual short-term memory (VSTM) (Marois and Ivanoff, 2005).
The AB refers to the inability to process two visual information targets within 500 ms of each other (Shapiro, Raymond and Arnell, 1997). This does not occur as a result of perceptual limitations but rather due to the inability to redirect attention in such a short time span. It is proposed that while the brain is processing information from the first target, the second target acts as a distraction and initiates the blink (Nieuwenstein, Potter and Theeuwes, 2009). The brain will therefore have limited ability to process a second target until the identification of the initial information is complete and full control is regained.
The PRP is similar to the AB however refers to the delay which occurs when two tasks must be performed in rapid succession (Marti, Sigman and Dehaene, 2012). The issue arises as a delay in performing the second action after completing the first (Figure 1). Further, the PRP offers an explanation as to why humans often struggle with multitasking (Sigman and Dehaene, 2008). While the cause of this phenomenon is unknown if a decision is made to complete a given task, it will then supersede any tasks that arrive soon after (Zylberberg et al., 2012). There is no way to eliminate the PRP however, with practice the delay which the interference causes can be minimized (Karlin and Kestenbaum, 1968).
VSTM is a short-term storage for visual information before further processing can occur (Xu and Jeong, 2015). There are multiple proposed explanations for limitations to VSTM including the possibility that there is a fixed, limited number of approximately 4 visuals that can be help in the VSTM. Alternatively, the resources of the VSTM may be divided to process a multitude of images simultaneously and potentially exceed the proposed fixed limit based on the complexity of the visuals.
The brain is a very powerful information processor, however, it is in no way perfect. Considerations like the AB, PRP, and VSTM reveal that we are in fact just human and that high degrees of multitasking are nearly impossible. While there is currently no way to surpass this limitation, the capacity of the human brain to problem-solve and think critically remains invaluable.
References
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