The Impact of Multitasking on Brain and Cognitive Functioning

Psychologist Claudia Méndez Rodríguez discusses the consequences of multitasking for the brain, working memory, and attention.

Introduction

In a hyperconnected society that operates in the here and now, multitasking has become a common practice. Responding to messages while watching a TV series, browsing multiple tabs on the internet, or consuming information across several platforms simultaneously are everyday activities. However, far from being an efficient skill, scientific evidence suggests that multitasking can have significant negative effects on various cognitive processes, particularly attention and brain functioning (Jung et al., 2026).

Attention in neuropsychology: definition and classification

The concept of attention has been studied by different authors, but no single definition has been reached because it includes complex mechanisms and numerous brain areas involved in the process. 

However, attention can be defined as the “mechanism directly involved in the activation and functioning of the processes and/or operations involved in the selection, distribution, and maintenance of psychological activity” (García Sevilla, 1997).

In other words, it is the system responsible for initiating and managing how we select, distribute, and maintain our attention and mental activity. 

This article emphasizes two types of attention: 

• Divided attention: the ability to attend to several tasks simultaneously by distributing resources (Kahneman, 1973).
• Alternating attention: the ability to shift the attentional focus between tasks (Baddeley, 1986).

What do we mean by multitasking?

Multitasking does not involve performing several complex tasks simultaneously, but rather rapidly switching between them. Traditionally, it is classified as divided attention; however, from a practical perspective, it is better understood as a process of alternating attention, since it involves rapid shifts in attentional focus between tasks rather than truly simultaneous processing (Lui and Wong, 2019). 

• An example of divided attention would be listening to music while driving, with both tasks being automatic and compatible (they do not interfere with each other because they do not require the same mental resources to be completed).
• An example of alternating attention (multitasking) would be studying while occasionally checking your phone. You do not do both things at the same time (because they interfere with each other, as they require the same mental resources); instead, you jump from one to the other. 

This constant switching between activities requires attentional and executive resources, creating a cognitive cost known as switch cost (Monsell, 2003), which consumes considerable energy because the brain needs to ‘reorient’ itself each time the task changes, based on the task’s characteristics and demands.

Multitasking attention paradigms in cognitive processing

According to Lui and Wong (2019), there are two major paradigms related to multitasking attention:

• On the one hand, there is the Concurrent Multitasking Paradigm (dual-task), which involves performing two tasks at the same time or with temporal overlap and is related to divided attention. In this case, the tasks do not require the same sensory pathways and therefore do not compete with each other.
• On the other hand, the Task-Switching Paradigm involves alternating from one task to another without performing them simultaneously and is related to alternating attention. In this case, the tasks require the same attentional resources, creating a greater risk of errors and slower performance. For this reason, engaging in this practice frequently is not recommended.

Consequences of multitasking for sustained attention

One of the most documented effects of multitasking is the presence of difficulties with sustained attention, which is the ability to maintain attentional focus and remain alert for long periods (Posner and Petersen, 1990). 

People who multitask frequently tend to show greater susceptibility to distraction and a reduced ability to filter out irrelevant information, suggesting impairment in attentional control mechanisms (Ophir, Nass, and Wagner, 2009). 

Additionally, intensive use of multiple simultaneous sources of information is associated with a reduced capacity for deep concentration, making it harder to sustain attention during prolonged tasks (Rosen et al., 2011). This particularly affects academic and professional performance, where sustained attention is essential.  

Meyer, Evans & Rubinstein (2001) found that switching between tasks can significantly increase the time needed to complete them. This phenomenon is explained by cognitive interference, which occurs when different tasks compete for the same mental resources. This explains why errors increase and execution speed decreases during multitasking, resulting in reduced productivity.

For example, if you write an email while talking on the phone, you may make writing errors, have to reread what you wrote or received, or even take longer to decide what to write. 

According to Lui and Wong’s (2019) study, errors or slowness during multitasking do not have a single cause, but rather reflect three different cognitive limitations:

1. Response selection: difficulty choosing which action to perform when several tasks are simultaneous, meaning that two complex responses cannot be selected at the same time.
2. Information retrieval and maintenance: difficulty keeping the rules or information from several tasks in mind at once. This affects the ability to remember what to do for each task.
3. Task reconfiguration (task switching): difficulty switching from one task to another. This involves adjusting the brain to new rules or contexts.

Multitasking is not a single skill, but rather a set of distinct mental processes. Therefore, some people may be good at certain types of multitasking and poor at others.

Impact of multitasking on other cognitive processes

Authors such as Mark, Iqbal, and Czerwinski (2020) describe the phenomenon of fragmented attention, in which attention is distributed across many things at once but only superficially, without going deeply into any of them. As a result, learning and remembering information over the long term becomes more difficult (Carr, 2010).  

Multitasking also impairs other fundamental cognitive processes: 

• Working memory: allows us to retain information briefly and manipulate it immediately. Information overload makes it harder to store and manipulate data in working memory, reducing efficiency in problem-solving (Baddeley, 2012). 
• Learning: switching between tasks interferes with the consolidation of information in long-term memory, affecting the acquisition of new knowledge (Foerde, Knowlton, and Poldrack, 2006), especially when one of the tasks is a digital distraction (Madore et al., 2020). 
• Decision-making: multitasking can lead to more impulsive and less thoughtful decisions because of the fragmentation of cognitive resources (Dux et al., 2009). 
• Creativity and problem-solving: the consequences of multitasking, specifically fragmented attention, are most apparent in settings where creativity and problem-solving efficiency are required, because the processes needed for these abilities are inhibited (Madore et al., 2020). 

Neurobiological effects: cognitive load and brain plasticity

At the neurobiological level, multitasking also has important implications. Neuroimaging studies have shown that intensive digital media use and multitasking are associated with changes in brain structure due to overuse of the area, particularly the prefrontal cortex, a region essential for the control of executive functions (Loh and Kanai, 2014). In addition, people who tend to multitask excessively have lower gray matter density in brain areas associated with cognitive control (Ophir, Nass, and Wagner, 2009).

Likewise, constant task switching can increase cognitive load and stress, activating neural systems associated with mental or cognitive fatigue (Miller and Cohen, 2001). This prolonged state can affect neural efficiency and brain plasticity (Mark, Gudith, and Klocke, 2008). For example, at the end of the day, after constantly switching between tasks, we may feel mentally exhausted even though we have not done physical work.  

On the other hand, multitasking may reinforce neural circuits associated with immediate reward, because dopamine is released when switching stimuli, which may encourage constant distraction habits (Alter, 2017). Deterioration has also been observed in the anterior cingulate cortex, which is associated with emotional control (Loh and Kanai, 2014).

Is it possible to train multitasking?

Although some research suggests that the brain can partially adapt to contexts involving high cognitive demands, most studies agree that it is not possible to perform multiple complex tasks efficiently without sacrificing performance (Karbach and Kray, 2009).  

To explain why multitasking is thought to be effective, we must consider the productivity illusion effect: people who multitask frequently tend to overestimate their actual performance, estimating it to be up to 30% higher than it really is. This bias is reinforced by dopamine release when completing small actions, such as answering emails or messages, producing a misleading sense of effectiveness even when the most important tasks remain unfinished (Sanbonmatsu et al., 2013).

Rather than training multitasking, the evidence points to the importance of promoting strategies such as (Vohale, 2025; Madore et al., 2020):  

• Monotasking: performing one task at a time. 
• Time blocking: devoting 30–40-minute blocks to a single task, without interruptions or notifications. 
• The two-minute rule: if something takes less than two minutes, do it immediately so it does not occupy space in working memory. 
• Nighttime digital hygiene: screen light affects nighttime rest, so it is advisable to stop using screens at least 30 minutes before going to bed to avoid disrupting the brain mechanisms underlying sleep.  
• Designing the context: when working or carrying out tasks, try to ensure that both the physical and digital environment are free of distractions and do not cause visual fatigue. 

Conclusion

In conclusion, attention is a complex process that allows us to select, distribute, and maintain mental activity, making it fundamental to cognitive performance. In this context, multitasking does not actually mean doing several tasks at once, but rapidly switching between them, which entails a high cognitive cost. Far from improving productivity, this constant shift in attentional focus reduces sustained attention, increases errors, and slows performance because of competition for limited mental resources.

In addition, multitasking negatively affects key processes such as working memory, learning, decision-making, and creativity, creating fragmented attention that makes deep concentration more difficult. At the brain level, it is also associated with structural changes, greater cognitive load, and distraction habits reinforced by immediate-reward mechanisms.

Although there is a belief that multitasking can be trained, scientific evidence indicates that frequent practice creates a productivity illusion rather than a genuine improvement in performance. Therefore, both in prevention and cognitive rehabilitation, it is more effective to adopt guidelines and strategies from cognitive stimulation, such as monotasking or organizing time into blocks, which promote more sustained, efficient, and higher-quality attention.

In an environment full of distractions, understanding the consequences of multitasking for the brain and learning to focus becomes a key advantage for performance and cognitive well-being.

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