Squirming is one of those behaviors so universal it barely registers as behavior at all. You do it in a hard chair, during an awkward conversation, and when someone’s fingers find a ticklish spot on your ribs. Babies do it before they can roll over. Earthworms do it to move through soil. Even physicists have borrowed the word, building mathematical “squirmer” models to describe how microorganisms propel themselves through fluid. What looks like a single restless motion actually spans a surprising range of biology, psychology, and physics, with each version of squirming serving a distinct purpose.
Why You Cannot Sit Still
The most familiar form of squirming is the one you do in your chair right now. Shifting your weight, crossing and uncrossing your legs, bouncing a knee: these small adjustments are not random noise from a bored nervous system. They serve at least two concrete purposes. The first is circulatory. Prolonged stillness compresses soft tissue and restricts blood flow, and your body’s pressure sensors nudge you into micro-movements to redistribute load. The second is metabolic, and it is surprisingly significant.
A study measuring energy expenditure across a range of non-exercise activities found that fidgeting while seated increased metabolic rate by about 54% over lying still, and fidgeting while standing pushed it up by roughly 94%.1PubMed. Energy expenditure of nonexercise activity Those are not trivial bumps. Over the course of a day, the cumulative calorie difference between a habitual fidgeter and someone who sits like a statue can add up to hundreds of calories. Researchers have coined the term NEAT (non-exercise activity thermogenesis) for this category of energy burn, and individual differences in squirminess appear to be one reason some people gain weight more easily than others on identical diets. Your restless colleague who cannot stop tapping their foot may genuinely be burning measurably more energy than you are.
Squirming, Attention, and ADHD
If you have ever watched a child with ADHD try to sit through a lesson, you have seen squirming taken to a conspicuous level. For decades, that fidgeting was treated purely as a symptom to suppress. More recent research tells a more interesting story: the squirming may actually help.
A quantitative analysis of fidgeting in people with ADHD found that participants fidgeted more during trials they answered correctly, and that fidgeting increased in later portions of a sustained-attention task rather than early on. People whose reaction times stayed most consistent, a sign of maintained focus, were the ones who fidgeted the most as the task wore on.2PubMed Central. A quantitative analysis of fidgeting in ADHD and its relation to performance and sustained attention on a cognitive task The interpretation gaining traction is that physical movement raises arousal levels in a brain that struggles to maintain them through cognitive effort alone. Squirming, in other words, is a self-regulation strategy. Telling a child with ADHD to stop fidgeting may be the equivalent of telling them to stop paying attention in the only way their brain knows how.
This does not mean all fidgeting is helpful for all people. The relationship between movement and attention appears strongest in individuals whose baseline arousal runs low. For neurotypical adults, squirming during a meeting is more likely a sign of boredom or physical discomfort than a cognitive lifeline. But the research has shifted the clinical conversation away from blanket suppression of movement and toward recognizing when it serves a function.
The Embarrassment Squirm
There is a distinctly different species of squirming that has nothing to do with chairs or attention: the full-body discomfort you feel when you are socially exposed. Blushing, looking away, touching your face, and shifting your body are all part of the embarrassment display, and they are remarkably consistent across people and cultures.
Research on nonverbal behavior during embarrassment has shown that body motion and speech disturbances increase sharply at the moment of social exposure, while eye contact drops.3British Journal of Social and Clinical Psychology. Changes in non‐verbal behaviour during embarrassment A separate study looked at how being observed changed self-directed fidgeting behaviors like face touching and gaze shifting, finding significantly higher frequencies of these behaviors when people were alone after an embarrassing event compared to when they were with someone else.4Journal of Nonverbal Behavior. Social Presence, Embarrassment, and Nonverbal Behavior That last finding is counterintuitive: you might expect people to squirm more when being watched, but the data suggest that the presence of another person actually constrains the fidgeting response, while being alone with your embarrassment lets the body express its discomfort more freely.
The evolutionary angle here is that embarrassment displays function as social appeasement signals. By visibly squirming, averting your gaze, and making yourself smaller, you communicate that you recognize you have violated a social norm. People who display embarrassment are generally rated as more likeable and trustworthy than those who brazen through a faux pas. Your body’s urge to squirm in an awkward moment is, in a sense, doing you a social favor.
Ticklishness and the Squirm Reflex
Tickle-induced squirming sits in its own neurological category. Unlike the slow fidgeting of a bored sitter or the self-conscious shifting of an embarrassed person, the tickle response is fast, involuntary, and surprisingly hard to trigger on your own. The fact that you cannot tickle yourself points to a neural mechanism that distinguishes expected sensory input from unexpected touch, and it is the unexpected kind that sets off the squirming reflex.
Recordings from the trunk region of the rat somatosensory cortex during tickling showed intense neural activity in most neurons, with rats responding to tickling with vocalizations, approach behavior, and spontaneous joy jumps.5Science. Neural correlates of ticklishness in the rat somatosensory cortex The finding that rats actively sought out more tickling suggests the squirming response to tickling is not purely defensive. It has a play component, which aligns with observations of tickle behavior in primates.
In wild chimpanzees, researchers documented that play panting, a laugh-like vocalization, occurred primarily when a chimp was being tickled or chased rather than when it was doing the tickling. A chimpanzee that heard its partner’s play panting tended to continue the tickling, meaning the squirming and vocalizing functioned as positive feedback that kept the interaction going.6PubMed. When does play panting occur during social play in wild chimpanzees? Tickle-induced squirming, then, is not just a reflex. It is a social signal that says “keep going” while simultaneously looking like “stop.” That ambiguity is part of why tickling is so peculiar: the body appears to fight what the brain is enjoying.
What Infant Squirming Tells Doctors
Some of the most clinically significant squirming happens in the first months of life. Newborns produce a repertoire of spontaneous movements that pediatric neurologists have learned to read like a diagnostic language. In the first weeks, healthy infants display “writhing” movements, complex whole-body patterns that look like slow, flowing squirms. Around the end of the second postnatal month, these give way to a different pattern called “fidgety” movements: small, elegant, continuous wriggles of the neck, trunk, and limbs that appear almost random in their timing and direction.7Early Human Development. Developmental transformations of spontaneous movements in early infancy
What makes this clinically powerful is that the quality of these squirming movements is one of the best early predictors of neurological outcome. General movements assessment, or GMA, has been shown to be 95% to 98% predictive of cerebral palsy when combined with brain imaging.8Clinical and Experimental Pediatrics. Spontaneous movements as prognostic tool of neurodevelopmental outcomes in preterm infants: a narrative review The absence of fidgety movements between roughly 9 and 20 weeks of corrected age is a red flag. If a baby never develops these characteristic little squirms, the risk of later neurological impairment is high.
Even among infants who do develop fidgety movements, the quality matters. Researchers have found that children who displayed only sporadic fidgety movements, rather than the normal continuous pattern, had outcomes similar to children who never developed fidgety movements at all when it came to functional mobility by age three to five.9PubMed Central. Are sporadic fidgety movements as clinically relevant as is their absence? The distinction matters for early intervention: parents and clinicians looking for reassurance that a baby is developing normally should watch not just for the presence of squirming, but for its quality, fluency, and variety. A richly varied repertoire of infant squirming is one of the earliest visible signs that the nervous system is wiring itself correctly.
Squirming at the Microscopic Scale
Physicists studying how tiny organisms move through fluid have built an entire modeling framework around the concept of squirming. The “squirmer” model, originally developed in the 1950s to describe how ciliated microorganisms propel themselves, treats a tiny swimmer as a sphere whose surface deforms in coordinated waves, much like the rippling cilia on a paramecium.10Annual Review of Fluid Mechanics. Fluid Dynamics of Squirmers and Ciliated Microorganisms The model has proven remarkably flexible. By tweaking how the surface motion is distributed, researchers can simulate “pushers” that thrust themselves forward from the rear, like many bacteria, or “pullers” that drag themselves forward from the front, like the algae Chlamydomonas, or “neutral” squirmers that generate a more symmetric flow.
These categories matter because the type of squirming changes how microorganisms interact with each other and with surfaces. Simulations have shown that at low concentrations, roughly 60% to 80% of squirmers accumulate near walls, with pushers and pullers attracted to walls more strongly than neutral squirmers.11PubMed Central. Hydrodynamic interaction of microswimmers near a wall In the near-wall region, pullers repel each other while pushers attract each other and form clusters. This has real implications for understanding biofilm formation: the reason bacteria colonize surfaces is partly a consequence of the physics of how they squirm.
As density increases, the collective behavior gets more complex. Neutral squirmers undergo a clear phase separation into a gas-like state and a clustered state, while strong pushers and pullers approach a hexagonal cluster arrangement more gradually.12PubMed. Hydrodynamics determines collective motion and phase behavior of active colloids in quasi-two-dimensional confinement Studies of dense suspensions have also revealed that close-range lubrication forces between squirmers play just as important a role as the long-range fluid flows, and that these near-field forces can suppress the dense clustering that would otherwise occur, leading to open, gel-like structures instead. For neutral squirmers with no force dipole, near-field collisions can even produce a globally polar-ordered phase, where all the squirmers spontaneously align and move in the same direction.13PubMed. Hydrodynamic interactions in dense active suspensions: From polar order to dynamical clusters
The squirmer framework has also been extended to model organisms that spin as they swim. The colonial alga Volvox, a hollow sphere of cells that rotates as it moves through water, required adding an azimuthal swirl component to the classic model to capture its locomotion accurately.14PubMed Central. Squirmers with swirl: a model for Volvox swimming These extensions keep the squirmer model relevant as researchers move beyond simple spheres to the messy, varied geometries of actual living things.
How Earthworms Squirm Through Soil
At a larger scale, earthworms are perhaps the most iconic squirmers in the animal kingdom. Their locomotion relies on coordinated waves of muscular contraction passing along a segmented body, alternately thickening and thinning sections to grip the soil and push forward. But how they create their burrows depends heavily on conditions underfoot.
Researchers testing two earthworm species across different levels of soil compaction found that burrowing strategy shifts with soil hardness. In softer soil, the worms created about two-thirds of their burrows through cavity expansion, essentially pushing the soil aside by squirming their bodies wider. In harder soil, they switched to ingesting the soil in front of them, eating their way forward. The balance between these two modes varied by species, but both shifted significantly toward ingestion as resistance increased.15Applied Soil Ecology. Earthworm burrowing modes and rates depend on earthworm species and soil mechanical resistance The earthworm’s squirm is not a single behavior but an adaptive toolkit that adjusts to the mechanical environment in real time.
Machines That Squirm
Engineers have increasingly looked at biological squirming as a design template for robots that need to navigate tight, unpredictable spaces. The challenge is that conventional rigid-bodied robots with wheels or legs are poorly suited for environments like the inside of a human intestine or a collapsed building. Soft, squirming motion offers an alternative.
One recent design mimics intestinal peristalsis using origami-inspired Kresling structures paired with one-way valves. A single servo motor drives alternating contraction and rotation cycles through chiral origami units, producing a continuous peristaltic wave that moves material in one direction, much like your gut moves food.16Biomimetic Intelligence and Robotics. A bio-inspired intestine robot utilizing soft origami Kresling structures to imitate peristaltic wave motion and transport The minimalist design is striking: rather than building a complex multi-actuator system, the robot achieves directional transport through the geometry of its folding pattern.
On the simulation side, researchers have used deep reinforcement learning to teach virtual soft-bodied animals to squirm effectively. By modeling an entire animal body as a deformable mesh with embedded muscles, the algorithm learned control policies that produced physically realistic squirming locomotion, animals that could be simulated in real time, controlled interactively, and that recovered from being poked or pushed.17ACM Transactions on Graphics. SoftCon These virtual squirmers are used in computer animation and games, but the same control-learning approach feeds back into real robotics, where teaching a machine to squirm gracefully through an unknown environment remains one of the harder open problems in the field.
The shared thread across all these domains is that squirming, whether performed by a fidgeting office worker, a developing infant, a bacterium near a wall, or an origami robot, is rarely purposeless. It is motion shaped by constraints, whether those constraints are a too-hard chair, a still-developing brain, the physics of viscous fluid, or the walls of a collapsing tunnel. The variety of contexts in which squirming appears and the specificity of its function in each one are what make it a richer topic than the word’s slightly undignified reputation would suggest.