The Reticular Activating System: The Brain’s Filter for Health, Performance, and Leadership

Every moment, the human brain is bombarded with millions of bits of sensory information, sounds, sights, bodily sensations, thoughts, and emotions. Yet we only become consciously aware of a fraction of this input. The mechanism responsible for this selective awareness is the Reticular Activating System (RAS), a network of neurons located in the brainstem that plays a central role in attention, arousal, motivation, and goal-directed behaviour.

At its core, the RAS acts as a filtering system. It determines what information is important enough to reach conscious awareness and what can be safely ignored. Without it, we would be overwhelmed by sensory overload. From a health and performance perspective, this filtering function is not neutral, it is shaped by beliefs, emotions, stress levels, and goals.

A simple real-world example illustrates this well. Imagine buying a new car, perhaps a red SUV. Suddenly, you begin noticing the same model everywhere on the road. Those cars were always there, but once your brain tagged them as relevant, your RAS prioritised that information. The same principle applies to opportunities, risks, and even symptoms in the body. What we repeatedly focus on trains the RAS to notice more of it (Desimone & Duncan, 1995).

In health, the RAS strongly influences stress and recovery. When an individual is chronically stressed, the RAS becomes sensitised to threat-related cues, emails, notifications, bodily sensations, or perceived criticism. This heightened vigilance keeps the nervous system in a state of arousal, impairing sleep, immune function, and metabolic health (McEwen & Morrison, 2013). Conversely, practices such as mindfulness, cognitive reframing, and intentional goal-setting can recalibrate the RAS to detect signals of safety and progress, supporting resilience and physiological regulation.

Performance is equally shaped by the RAS. Athletes, executives, and high performers often describe being “locked in” or “in the zone.” Neurobiologically, this reflects an efficiently tuned RAS that enhances focus on task-relevant information while suppressing distractions. Research shows that attentional control and motivation are closely linked to RAS-mediated arousal systems, particularly in demanding or high-stakes environments (Aston-Jones & Cohen, 2005).

In leadership, the implications are profound. Leaders do not just manage tasks; they shape attention, both their own and that of others. A leader who consistently focuses on problems, risks, and scarcity will unconsciously prime their RAS (and their team’s attention) toward threat. In contrast, leaders who clearly articulate purpose, values, and vision help direct collective attention toward solutions, learning, and growth. Over time, this attentional bias influences decision-making, emotional climate, and organisational performance.

Ultimately, the Reticular Activating System reminds us that attention is not passive. What we repeatedly think about, emotionally react to, and prioritise becomes neurologically reinforced. By consciously aligning focus with health, high performance, and effective leadership, we can train the RAS to work for us rather than against us.

References:

Aston-Jones, G., & Cohen, J. D. (2005). An integrative theory of locus coeruleus–norepinephrine function: Adaptive gain and optimal performance. Annual Review of Neuroscience, 28, 403–450. 

McEwen, B. S., & Morrison, J. H. (2013). The brain on stress: Vulnerability and plasticity of the prefrontal cortex over the life course. Neuron, 79(1), 16–29. 

Desimone, R., & Duncan, J. (1995). Neural mechanisms of selective visual attention. Annual Review of Neuroscience, 18, 193–222