The 300,000 year old history of our species is one of migrations made possible by our biological and cultural adaptations. From their East African cradle, homo sapiens now occupy every longitude and latitude of the world. As a generalist species with a penchant for story-telling, socializing, teaching, learning, technology, and engineering, we have transformed our environments to a degree that would be unrecognizable to our ancestors. Cities or farms would be unimaginable 50,000 years ago and factories or supermarkets would be unfathomable to our ancestors from 500 years ago. These transformations have occurred in the proverbial “evolutionary blink of an eye” with scarcely an opportunity for our genetics to keep apace. Even with genomes (mostly) left behind, our cultural innovations have led to an unprecedented boon to our species as evidenced by common metrics such as population size, life expectancy, and gross domestic product (GDP). As with most things in biology, the forces of evolution loom and gains are often associated with trade-offs. The evolutionary mismatch hypothesis states that there are diseases that are more prevalent, or more severe today than in the past because our bodies are maladapted to our constructed environments. However, the consequences of these mismatches do not necessarily manifest themselves in disease states, but day-to-day human performance can also be affected by engineered environments that are misaligned to our biology.

The emergency department is one such system. The ecology of the emergency department with the realities of 24/7 staffing, the pressures of volume based economics, and the diversion of attention from the patient to the electronic health record lead to impaired interoception, metacognition, and mindreading. This in turn pushes decision making to be reflexive rather than reflective and superficial rather than insightful. For example, as a diurnal species, nighttime sleep is a homeostatic necessity. The disruption of this sleep-wake sleepy cycle deleteriously impacts interoception. Emergency physicians routinely rotating from night to day and back are routinely tasked with making impactful decisions late at night and during the early morning hours. Another driving force that is ever-present in the emergency department is the pressures of the volumes-based economics. In this model, the physician “productivity” is optimized and patients are moved in assembly line fashion through the department. This optimization for productivity and efficiency nudges decisions to become reflexive. In controlled experiments, metacognitive sensitivity (accurately confident in your decision) decreases when decision making is forced or sped up. This is a routine condition of the volume-based model of care in the emergency department. Lastly, as medical records have become digitized, the electronic health record has essentially become the locus of activity in the emergency department. Physicians spend more time within the EHR than in direct observation of the patient. This reprioritization of attention has created a cohort of physicians that have become proficient retrieving information from the EHR and (over)reliant on imaging and laboratory data at the expense of under-developing the skill of mindreading. 

On the patient side of the ecosystem, emergency department patients often represent a population with significant and often unrecognized socio-cultural complexities and extensive disease co-morbidities. Prevalent emergency department diseases with significant burdens of morbidity and mortality such as heart attacks, strokes, and sepsis not only rely on timely recognition but are famously difficult-to-diagnose because they lack reliable biomarkers (future essay). Stroke can masquerade as vertigo or dizziness and heart attack can present as heartburn. When patients are reflexively triaged and categorized (future essay) in the context of volume pressures, the likelihood of  miscategorization increases. These mis-categorizations serve as priors and can cascade through the encounter especially when metacognition, mindreading, and interoception is impaired. Overall, the effects can be obviously catastrophic at the individual patient level, but also insidiously harmful at the population level (future essay).

As a people – conditioned by modernity, insulated by culture, and detached from the natural world – considering our evolutionary history might have the veneer of arcane academia and impractical luxury. However, the weight of phylogeny imposes invisible but tangible constraints in our socially constructed niches and the phenotypes within those niches.  Nonetheless, possibly more than for any other species, our evolutionary history has also built within us multiple layers of adaptivity from the genomic to the connectomic to the behavioral and the social that enable us to stretch our evolutionary constraints and survive in a broad range of physiological and psychological environments. (next essay).

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