Instinctual Behaviors

 Hon'nō-tekina kōdō [本能的な行動]

Here’s a detailed breakdown of how humans instinctually react to danger — drawing from neuroscience, psychology, evolutionary biology, and behavioural science — with full references so you can trace the research. Because you’re working on self-defense, emotional regulation, situational awareness and automaticity, this will give you a solid foundation to integrate into your training.

1. What constitutes a “danger” or threat

A “threat” can be immediate (physical harm) or potential (possible harm) and triggers alarm systems in the brain. For example, the review “Defensive responses: behaviour, the brain and the body” states that predatory threat has been a major selective pressure shaping behaviour.  

In simpler terms: when the brain perceives a stimulus (sound, sight, movement, environment) that signals risk/danger, it activates instinctual defence responses.

2. Core instinctual responses to danger

2.1 Fight / Flight / Freeze (and related responses)

• The classic fight or flight response: When faced with threat, the body’s sympathetic nervous system kicks in, preparing muscles for action, increasing heart rate, redirecting blood flow, dilating pupils, suppressing non-essential systems.  

• Freeze (or attentive immobility): When escape or fight seems impossible, the organism may freeze—becoming motionless, assessing options, reducing detection. In humans, studies show reduced body sway and bradycardia (slowed heart rate) in some freeze-like states under threat.  

• Other responses: Some frameworks include “fawn” (appease, comply to reduce threat) especially in interpersonal / chronic social danger rather than sudden physical threat.  

2.2 Neuro-circuitry & brain mechanisms

• The review “The defense system of fear: behavior and neurocircuitry” identifies the network: the Amygdala (central nucleus) projects to mid-brain (Periaqueductal gray or PAG), hypothalamus and brainstem — these coordinate responses like fight, flight, freezing, autonomic arousal.  

• Further: behavioural tendencies depend on threat imminence (how close, how severe) and context. The review “Defensive responses: behaviour, the brain and the body” indicates the brain-body integration involves endocrine, immune, gastrointestinal, reproductive systems in modulating threat response.  

• Instinctive defensive behaviour isn’t purely reflexive: research from the Sainsbury Wellcome Centre found that animals (mice) used learning/memory/cognitive maps to locate shelter under threat, implying that responses are rapid but involve memory/space mapping, not just raw reflex.  

2.3 Physiological changes (what the body does)

When the threat response is triggered:

• Heart rate ↑, breathing quickens, blood is shunted to major muscle groups, non-essential functions like digestion are suppressed.  

• Pupils dilate, hearing may sharpen, pain perception may diminish (so one can act despite injury) — known as hypoalgesia in defence behaviour.  

• In freeze or tonic immobility, there may be bradycardia, reduced movement, expressive tachycardia depending on context.  

3. Evolutionary and adaptive significance

• These responses evolved because they increased survival: recognising and reacting to predators, threats, rivals, hostile environments. The fear/defence system is part of the “ethogram” of species-specific behaviours.  

• For humans, even though predators are less common now, the same systems underlie responses to modern threats (e.g., interpersonal violence, accidents, surprise). That’s why you may still get a “fight/flight” surge when a car swerves into your lane.  

• The adaptive variable is threat imminence and escapability: If escape is possible, flight is favoured; if threat is immediate and unavoidable, freezing or fight may be more probable. The picture-stimulus human study (“Stop or move: Defensive strategies in humans”) demonstrates this: when a gun was directed toward a subject (high risk, low escape) immobility was more likely; when escape looked possible, flight.  

4. Implications for self-defense, situation awareness, and training

Since you’re developing drills around self-defense, attention, automaticity, the above translates into actionable insights:

• Know your response set: Recognizing when your body is primed for fight/flight/freeze can help you catch the reaction early — e.g., pounding heart, tunnel vision, sudden urge to run, urge to stand and fight, feeling “locked up”.

• Threat assessment & decision making: Because defence responses are related to threat closeness and perceived escape routes, training to scan for escape routes or assess threat imminence can modulate which defence pathway is activated. For example: if escape is assessed as viable, training can favour flight (or reposition); if not, then fight or controlled freeze/refocus.

• Train on awareness of physiological signs: For example, when heart rate spikes, breathing fast, tunnel-vision, you may be entering a high-arousal state. Use breathwork / regulation to bring parasympathetic activation back. (This links back to your interest in breathwork + makiwara + situation awareness.)

• Use freeze/immobility deliberately: In some situations (especially in covert/intrusion/self-defense contexts) staying still, reducing movement, blending may be more effective than immediate flight or fight. This should be a trained option rather than purely reactive.

• Context and memory matter: Training your environment, memory of landmarks, escape paths, decision trees, will help your instinctive responses be effective rather than chaotic — i.e., the research emphasises that instinctive reactions are not mindless reflexes but rapid computations using past learning.  

• Avoid maladaptive activation: These survival systems can mis-fire (e.g., responding with full fight/flight to non-threats, causing chronic stress). Recognising when the system is over-triggered (e.g., via everyday stress) helps maintain readiness without burnout.  

5. Practical drills & reflection tasks for your context

Here are some suggestions tailored to your interests (self-defense resilience, situation awareness, attention sharing, automaticity, etc):

• Drill: Threat imminence / escape mapping

• Scenario: From a neutral posture, as you walk through an environment (could be your training space or home), identify three possible escape or safe-zones if a threat arises. This trains the “escape/flight” branch of your instinct.

• Then assess a scenario where escape is blocked (e.g., cornered) and train for fight or controlled freeze (immobility, blending, assessing next move).

• Debrief: After each scenario, note your physiological response (heart rate, breathing, tension) and what instinct path felt most natural.

• Drill: Freeze/immobility awareness

• Begin with a low-stimulus threat (e.g., verbal challenge or sudden sound) and practise physiological awareness: notice when your body slows, your movement reduces, maybe you feel “stuck”.

• Then train the pause → decide moment: acknowledge the freeze impulse, use a quick breath reset, then choose fight/flight/other strategy consciously.

• Reflection: What triggers your freeze? Is it threat assessment, lack of escape, surprise? Document this.

• Breathwork integration

• After an induced high-arousal reaction (e.g., quick sprint, or surprise stimulus), use a 2-minute focused breath pattern (e.g., inhalation 4, hold 1, exhale 6) to stimulate parasympathetic recovery. Note how this down-regulates your fight/flight physiology.

• Over time you’ll build awareness of the shift between sympathetic activation and recovery — this is key to automaticity: recognising when the system has ramped up and choosing response rather than reacting purely on instinct.

• Situation awareness & memory mapping

• Because instinctive defence relies on memory/cognitive mapping (as above), practise remembering safe spots, cover/escape paths, vantage points in familiar environments (e.g., home, gym, workplace).

• Then simulate a threat scenario: imagine you become aware of a threat in your mapped environment; run through your internal process: sense (via perception) → assess (imminence/escape) → choose (fight/flight/freeze) → execute.

• Journal: What cues did you detect? What memory/mapping kicked in? How quickly was decision made? How did physiology feel?

6. Key caveats and complexities

• These responses are not purely reflexive: As noted, instinctive defensive behaviour involves rapid “computational” processes using memory and spatial mapping rather than simply raw reflex.  

• Individual differences matter: Past trauma, learned threat cues, context (physical, social, cultural) shape how a person responds. E.g., someone with prior victim-experience may default to freeze/fawn more readily.

• Modern threats and contexts can confuse our systems: Because the brain’s alarm system evolved for physical threats (predators, immediate danger) and now we face abstract threats (social aggression, psychological threat), the same responses can be triggered in less adaptive ways (anxiety disorders, chronic stress).  

• Training matters: Because these systems operate fast, you cannot just “think” your way out — but by training physiological awareness, decision trees, mapping you increase the chance your chosen response is effective rather than maladaptive.

• Recovery and regulation are crucial: After a high-threat response, the body needs time and tools to return to baseline (rest/digest). Neglecting this leads to wear and reduced capacity for future responses.