Key Terms:

A list of terms you’ll hear us use.

Autonomic Nervous System (a.k.a. ANS)

The autonomic nervous system regulates a number of functions in the body.  In the context of content from Here this NOW, ANS is referred to in relationship to the Polyvagal TheoryThe ANS is responsible for modulating our automatic functioning (i.e. breathing, heart rate, digestion, etc.) and is comprised of two branches, the sympathetic and the parasympathetic.  The parasympathetic branch contains the vagus nerve which has two distinct hierarchically-organized circuits.  The two circuits are the ventral and the dorsal vagal.  The ventral vagal supports the realm of social engagement.  When messages from the body travel this circuit, we feel safe in our bodies and are able to access the higher functioning parts of our brain.  In school environments, we want to recruit the realm of social engagement through intentional cues of safety in the environment and human interactions.


The unconscious biological capacity to synchronize our physiological state with another person.  Example:  A mother sways in a rhythmic pattern from side to side while singing softly to her baby in order to calm the baby’s dysregulation.  As the baby settles, momma settles too.

Physiological State (a.k.a. autonomic state or “felt sense”)

In Polyvagal Theory, physiological and autonomic state are synonymous terms.  They refer to the body’s state.  More specifically, the physiological state reflects the active pathway(s) of the autonomic nervous system (ANS).  It is commonly reflected in the sensations we experience in our body.  Example:  Your heart rate suddenly increases when you are startled.  This is a shift in your physiological state.  

Sequence of Engagement

Regulate (1st) → Relate (2nd) → Reason (3rd) |  The sequence of engagement is a helpful heuristic developed by Dr. Bruce Perry.  The heuristic explains how the brain processes and organizes information.  Messages that travel along our sensory pathways are processed bottom-up in the brain.   In other words, information is being transmitted and organized from lower and unconscious regions of the brain to higher, more conscious areas of the brain.  Therefore, the “learning brain” is most easily accessed when lower regions of the brain are efficiently organizing and effectively integrating sensory input from the external and internal worlds.

Social-Emotional Learning (SEL)

Social-emotional learning (SEL) is a term commonly used to describe sequential neurodevelopmental capacities that give rise to our ability to regulate our social and emotional experiences.  

What does that mean more simply?
SEL refers to our ability to manage our social and emotional experiences in order to access our uniquely human abilities – empathy, meaning making, rational thinking, delaying gratification, planning and executing goals, etc.  The development of these human capacities and our ability to access them results from ample opportunities with attuned relationships and somatosensory experiences that help our body interpret and process cues of safety.  

We often think of social-emotional learning and functioning as learning that is apart from academic learning.  Truth be told, social-emotional functioning directly impacts a child’s ability to learn.  If a child’s sequential social-emotional development has been interrupted or disrupted by trauma, their availability for learning will be diminished.  

The essential priority in supporting a child’s social and emotional growth is safety a felt sense of safety – in the home and school environment.  Despite what many SEL companies claim, creating safety and enhancing a student’s social and emotional growth is not best accomplished through explicit instruction and lesson plans.  It’s not something that can be scheduled once or twice a week for forty minutes .  In school, a felt sense of safety spontaneously emerges during authentic exchanges between individuals, in the context of caring and attuned relationships with a physiologically regulated adult.  

POLYVAGAL-INFORMED Social-Emotional Learning

A Polyvagal-informed perspective of SEL contends that these innate capacities do not develop in the same ways that academic capabilities do.  Academic skills are not spontaneously biologically occurring.  For example, the ability to read and comprehend material will not occur spontaneously in the absence of being taught the foundational skills of reading (i.e. recognizing letter symbols and the corresponding sounds).  Likewise, someone will not spontaneously develop the capacity to solve algebraic equations in the absence of learning how to recognize symbols, manipulate and compute numbers.  

In education, we have mistakenly made SEL a content subject area of focus and instruction.  Why is this a problem?  It reinforces the notion that SEL is another “thing” to do in education and not the necessary context for learning.  

We can refine etiquette and social norms (though they need to be culturally responsive and/or community-defined) through explicit instruction and reinforcement (i.e. “it’s thoughtful to hold the door for the person behind you.” Or, “say ‘please’ when you request something and ‘thank you’ when you receive something). But true social-emotional learning emerges as a result of safety, belonging, and sufficient somatosensory experiences.  Therefore, it needs to be a primary priority in school settings.


The somatosensory system is made up of the sensory pathways that constitute the felt sense.  Somatosensory commonly refers to three sensory pathways: tactile, proprioception, and vestibular.  

  • Tactile is the sense of touch.  We can experience two kinds of touch:  deep pressure and light touch.  Deep pressure, for most people, stimulates the parasympathetic branch of the autonomic nervous system and settles or calms the body.  Light touch, conversely, has an alerting effect for most people.  
  • Proprioception refers to the ability to sense the body in space – including directionality and position.  It’s derived from input to the joints, tendons, and muscles.  
  • Vestibular refers to the sense of balance.  It results from input processed in the middle ear.  It is typically derived from head motions that are side to side, back to front, circular (i.e. spinning), or up-side down.  

The Polyvagal Theory

A theory proposed by Dr. Stephen Porges that revolutionizes our understanding of human experience and human behavior.  Porges contends there is an intervening variable influencing human behavior and human experience – physiological state.  Porges argues that our default defense mobilization that supports survival is down-regulated with ample cues of safety in the environment and in our relationships.  In other words, we must experience a felt sense of safety in our bodies in order to access our higher cortical capacities (i.e. empathy, compassion, rational decision-making, executive functioning, etc.).  


Many people define trauma as a horrific event or experience.  Trauma can result from such circumstance(s).  But trauma is the residue of overwhelm held in the body’s memory.  It often results from too much, too fast, too soon or chronic, unrelenting toxic stress.  

When thinking about children that have experienced trauma, we most often describe developmental trauma.  Developmental trauma refers to chronic, unrelieved toxic stress that sensitizes a child’s stress response system to potential cues of danger and threat in the environment.  Consequently, these children are more likely to be reflexively reactive to stimuli in the environment that connotes threat, danger, risk or novelty in their body experience. 

Window of Tolerance

This term was first coined by Dr. Dan Siegel.  Although there is nuance among experts and practitioners about the exact meaning of “window of tolerance,”  HTN seeks to help educators widen their window of tolerance. We define widening the window of tolerance as increasing distress tolerance by increasing one’s ability to fluidly shift physiological state.  



Center on the Developing Child at Harvard University. (2011, September 29).  Toxic Stress Derails Healthy Development.

Perry, B. & Szalavitz, M. (2017).  The Boy Who Was Raised As a Dog.  Basic Books.

Porges, S. (2017).  The Pocket Guide To The Polyvagal Theory:  The Transformative Power of Feeling Safe.  W.W. Norton and Company Ltd.  

Siegel, D. (2010).  Mindsight:  The New Science of Personal Transformation.  Bantam Books.

Warner, E., Cook, A., Westcott, A., Koomar, J. (2014).  SMART (Sensory Motor Arousal Regulation Treatment):  A Manual For Therapists Working With Children and Adolescents – A “Bottom Up” Approach to Treatment of Complex Trauma.  The Trauma Center at JRI.  


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