Nail-biting, procrastination, self-harming: The evolutionary origins of bad habits

Patterns that look self-defeating often have a deeper logic, according to a new psychological analysis by Charlie Heriot-Maitland, a clinical psychologist whose work examines why people harm themselves in small, familiar ways. He argues that behaviors such as procrastination, perfectionism, harsh self-talk, and avoidance arise from the brain’s drive to survive, not to maximize happiness.

From this perspective, the mind sometimes chooses a limited, predictable harm to avoid a threat that feels larger or more uncertain. The idea reframes self-sabotage as a protective strategy that once helped humans endure danger. It also challenges the assumption that such behaviors are irrational or meaningless. Instead, they may reflect how the brain manages risk when outcomes feel unknown.

“Our brain is a survival machine. It is programmed not to optimize our happiness and well-being, but to keep us alive. It needs us to exist in a predictable world. It does not like surprises. It does not want us to be caught off guard,” Heriot-Maitland explained.

The brain’s threat system evolved to spot danger quickly. That sensitivity helped the species survive, but it also means modern life can trigger alarms even when no physical threat exists. Emotional risks, such as rejection or failure, can feel just as powerful. When uncertainty rises, the brain often prefers a known cost over an unknown one.

“Being exposed to threats and dangers is bad enough, but the most vulnerable state for us humans is being exposed to unpredictable threat,” Heriot-Maitland said. “Our brain cannot allow this, and will intervene to give us more controlled, predictable versions of threat.”

In everyday life, that intervention can look like delay or avoidance. Putting off a project may cause stress, yet it can feel safer than facing the possibility of failure. Steering clear of someone may reduce loneliness in the short term if rejection feels likely. These choices hurt, but they are familiar. The brain often values that familiarity.

“Our brain would rather we were the arbiter of our own downfall than risk being floored by something external,” he added. “It would rather we were well-rehearsed in receiving internally-created hostility than risk being unprepared for it from others.”

Self-sabotaging behaviors appear along a wide spectrum. On one end are everyday habits such as nail-biting, skin picking, pessimism, and self-criticism. On the other end are more severe forms of self-harm, often linked to trauma. Heriot-Maitland treats these patterns as connected rather than separate categories.

Perfectionism and procrastination illustrate how different routes can lead to the same goal. Procrastination diverts attention away from a feared task. Perfectionism narrows attention so tightly that mistakes feel less likely. Both aim to avoid failure. Both can increase stress and burnout.

Self-criticism serves a similar function. Critiquing yourself can create a sense of control or improvement, even when it deepens distress. These reactions reflect what Heriot-Maitland calls a “neurological hijacking,” where the threat system takes over imagination and reasoning. When fear rises, the mind fills with vivid predictions of what could go wrong.

“Our brains have evolved to favor perceiving threat, even when there isn’t one, in order to elicit a protective response in us,” he said. “We have all inherited a highly sensitive threat-detection and threat-response system.”

One risk of these patterns is that they can become self-fulfilling. If you expect to fail, effort may drop. Performance then suffers, confirming the original fear. Avoiding people because rejection feels likely can prevent relationships from forming at all.

“If we think we are not very good at something, we may not try our best and then end up performing worse than we would have had we made a different prediction,” Heriot-Maitland explained to The Brighter Side of News. “Or if we think someone doesn’t like us, and we avoid them, then our fear of rejection may have stood in the way of creating a relationship.”

"Even when the cost is clear, simply trying to stop these behaviors often fails. That is because they serve a function. Addressing them requires understanding what they protect against, not just pushing them away," he continued.

Heriot-Maitland uses a vivid metaphor to explain this process. Controlled explosions are planned acts of damage meant to prevent greater harm. The analogy comes from bomb disposal, where experts detonate explosives in safe settings to avoid catastrophe.

“The bomb squad are not our enemies,” he says. “They are protecting something big; something hurt; something wounded or painful.”

In mental health, the “explosions” may link back to earlier experiences. A threat, trauma, or loss can teach the brain to expect danger. The controlled harm that follows does not mean the pain is acceptable. It means the system learned a way to cope.

“In many cases, it may be linked to a difficult life experience,” he says. “The controlled explosions do harm us though; we must not lose sight of that either.”

Effective psychological help, Heriot-Maitland argues, focuses on the underlying pain rather than the surface behavior. That process is demanding and rarely quick. It often involves building a sense of safety around feared situations and grieving unmet needs.

“Resolving underlying harm can often involve both of these two aspects,” he explains, “creating safeness around the feared situation and feeling; grieving the loss of having a core need in that situation that was unmet, denied or dismissed.”

Breaking the cycle does not come from more self-criticism. That response strengthens the same neural pathways. Instead, compassion creates room for learning new habits. Neuroplasticity allows change, but it takes time and intention.

“To instill these compassionate motivations into a process like this is not just ‘a given’,” Heriot-Maitland says. “It takes time, effort, and intentionality.”

Understanding the survival roots of self-sabotage offers a shift in perspective. Recognizing the protective role a behavior once played can reduce shame while still acknowledging harm. The goal is neither to fight these behaviors nor to let them run life.

“We don’t want to fight these behaviors, but nor do we want to appease them and let them carry on controlling, dictating, and sabotaging our lives,” Heriot-Maitland concludes. “There are choices we have here.”

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