For decades, paleoanthropologists have largely agreed that somewhere along the evolutionary course from apelike ancestors to modern humans, our bodies got dramatically larger. However, one lingering mystery has been when this intense growth began.

Did our ancestors gradually grow bigger over millions of years? Did the shift coincide with the emergence of the genus Homo? Or did it occur later, after some of the earliest human species had already appeared?

A new study published in the Proceedings of the National Academy of Sciences (PNAS) argues that the answer is more complex than any single theory has suggested.

Rather than supporting a single long-standing hypothesis, researchers used a sophisticated statistical method to show that human body size likely followed two evolutionary courses simultaneously: a slow, steady increase spanning millions of years, punctuated by a much larger leap in later members of the genus Homo.

The findings help reconcile decades of conflicting research while offering one of the clearest pictures yet of how, and perhaps why, our ancestors evolved into larger-bodied humans.

“Despite its central role in hominin evolution, there is little consensus on how body size increased through time,” researchers write. “We provide strong evidence for a marked size increase in later-occurring Homo, alongside a moderate general increase over time among all hominins.”

Body size is one of the defining characteristics of an organism. In humans and our extinct relatives, it has been linked to everything from brain expansion and walking efficiency to metabolism, hunting behavior, and the ability to travel across increasingly large landscapes. Understanding when body size changed, therefore, helps researchers reconstruct not only what our ancestors looked like, but how they lived.

Yet despite decades of fossil findings, scientists have struggled to agree on the evolutionary pattern behind those changes.

Some previous studies suggested that hominins simply became larger over time. Some contended that body size remained relatively stable until the emergence of Homo. Still others have proposed that the real transformation arose only after early species such as Homo habilis, often regarded as one of the first members of our genus.

According to researchers, one reason for the disagreement is that earlier analyses typically examined these competing ideas independently. They also often failed to account for uncertainties inherent in the fossil record, including disagreements over species classification, differences in body mass estimation methods, and uncertainties in evolutionary relationships among fossil species.

To address those limitations, researchers compiled one of the largest hominin body-size datasets assembled to date, incorporating body mass assessments from 386 fossil specimens representing 21 different taxa.

They then analyzed the data using Bayesian phylogenetic generalized linear mixed models—a statistical approach that accounts for evolutionary relationships while encompassing multiple layers of uncertainty.

The team repeated its analyses across 1,000 different phylogenetic trees and 1,000 separate datasets, allowing them to test whether the overall pattern remained consistent despite uncertainties.

The results pointed to two simultaneous trends.

The first was a modest but persistent increase in body size across the hominin family as a whole. On average, body mass increased by roughly 2 pounds (0.9 kilograms) every million years, suggesting that larger bodies gradually became more common throughout human evolution.

However, the second trend proved far more dramatic.

Instead of all members of Homo becoming substantially larger, the researchers found the strongest evidence for a distinct jump in body size among later members of the genus, particularly species that appeared after Homo habilis. That pattern regularly emerged regardless of how the fossil data were analyzed.

In other words, early members of Homo may not have represented the major biological turning point scientists once assumed.

This finding disputes a common assumption that simply belonging to the genus Homo meant possessing a significantly larger body. Instead, the study suggests that some hallmark features traditionally associated with humans, including larger body size, may have evolved after the genus’s origin.

That interpretation also corresponds to broader changes that occurred later in human evolution.

Researchers note that this period coincides with evidence for more efficient upright walking, greater reliance on meat consumption, and expanding home ranges. Larger bodies may have been both a consequence of and a contributor to those behavioral and ecological shifts.

The study likewise reinforces another growing theme that evolution rarely follows a straight line.

Species such as Homo floresiensis, often nicknamed the “Hobbit” because of its diminutive stature, and Homo Naledi frequently appeared as outliers with unusually small body sizes despite belonging to relatively recent branches of the human family tree. Their existence demonstrates that body size did not simply increase in a uniform march toward modern humans.

Instead, evolution repeatedly experimented with different solutions depending on local environments and ecological constraints.

The researchers also argue that part of the longstanding disagreement over body-size evolution stems from the fossil record itself. Different studies have estimated fossil body masses using different skeletal elements, comparison populations, and statistical techniques, sometimes producing substantially different results for the same individual.

By expressly incorporating those uncertainties into their analysis, rather than treating them as fixed values, the new framework seeks to capture the range of plausible evolutionary scenarios rather than relying on a single interpretation.

Even so, researchers caution that important questions remain unresolved.

Improved fossil discoveries, more accurate body-mass estimation methods, and a better understanding of species relationships could all further refine the picture. The study also does not explicitly account for sexual size differences between males and females, which may have been greater in some early hominin species than in modern humans.

Nevertheless, the wider conclusion is intriguing.

Rather than choosing between competing theories, the evidence suggests both contain elements of the truth.

Body size did increase gradually across the hominin lineage. But the most considerable leap appears to have occurred later, after the earliest representatives of Homo had already evolved.

That conclusion may help settle one of paleoanthropology’s longest-running debates while showing how advances in statistical methods are transforming scientists’ ability to extract new insights from fossils that have often been studied for decades.

“Overall, these findings bring clarity to a fundamental question in human evolution and show how the application of rigorous phylogenetic comparative tools can unlock patterns previously hidden in the fossil record while accounting for multiple sources of uncertainty,” researchers write. “By reconciling conflicting findings within a single framework, our results clarify key evolutionary transitions and highlight the complex nature of body size change in human evolution.”

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

The future of military artificial intelligence may not be a single all-knowing machine directing a battlefield from a distant command center. Instead, DARPA is preparing to explore enormous collectives of AI agents capable of organizing themselves, dividing up missions, adapting to chaos, and continuing to operate even when some members of the group fail, disappear, or go rogue.

The Defense Advanced Research Projects Agency (DARPA) has formally launched a new effort called Decentralized Artificial Intelligence by Controlled Emergence, or DICE, aimed at developing AI collectives that can operate in contested environments without requiring a human or central AI planner to explicitly direct every action.

By the program’s final phase, DARPA wants researchers to test simulated collectives involving as many as 100,000 AI agents exchanging up to 1 million messages as they work toward shared objectives.

A recently released solicitation notice describes DICE as a 36-month effort divided between decentralization, adversarial robustness, and large-scale testing.

“Future conflicts will unfold at machine speed, and the current centralized planning and scripted orchestration approach is too slow, too rigid, and too predictable for the hyper-dynamic, contested environments of the future,” researchers write. “Surprise, adaptability, and resilience will depend on the ability to compose and recompose AI capabilities on demand.”

The basic premise behind DARPA’s DICE program is that today’s approach to multi-agent AI has a serious weakness. Most systems involving multiple AI agents still rely on some form of central orchestrator.

Think of it as a manager overseeing a team of specialized employees. One AI agent might gather information. Another analyzes it. A third creates a plan. A fourth executes a particular task. But somewhere in the system, a central planner or workflow typically decides who does what and combines the results.

That works reasonably well for predictable tasks. However, DARPA argues it may be dangerously vulnerable on a battlefield.

A central orchestrator creates a bottleneck because every increasingly complex mission must ultimately flow through a single decision-making structure. As the number of agents, roles, and interactions grows, the central planner must absorb more information, preserve greater context, and coordinate an expanding web of specialized systems.

Eventually, DARPA says, even an AI orchestrator can hit the context and inference limits of its underlying foundation model. There is also a more obvious military problem. A central command node is a single point of failure.

If communications are degraded, information arrives late, or the orchestrator itself is compromised, errors can potentially spread throughout the entire AI collective.

In a future conflict where electronic warfare, cyberattacks, deception, and broken communications are expected rather than exceptional, that vulnerability could be catastrophic.

DICE proposes a radically different model.

Rather than having a central AI issue instructions, individual AI agents would communicate directly with one another. They could form temporary teams, divide missions into smaller tasks, negotiate roles, combine incomplete information, and reorganize themselves when conditions change.

DARPA compares the idea to the architecture of the internet, where resilient global behavior can emerge from relatively simple local rules and decentralized interactions.

Essentially, an AI agent might receive a mission and determine that only part of the objective falls within its capabilities. The agent could volunteer to handle that portion and broadcast the remaining problem to neighboring agents.

Another agent might take the next task. Others could compete to perform the same job, potentially bidding based on cost or capability. Through repeated local interactions along with distributed consensus, the collective could gradually assemble its own mission plan.

If an agent fails, the entire mission does not necessarily need to be replanned. Its particular task could simply be offered back to the collective.

DARPA calls the larger concept “controlled emergence.”

Similar systems already exist in nature. Ant colonies, or flocks of birds, can engage in surprisingly complex group behavior even though no individual member possesses a complete understanding of the collective.

Computer scientists have long studied similar phenomena. DARPA’s solicitation even points to Conway’s Game of Life, the famous mathematical simulation in which extraordinarily complex patterns can emerge from a handful of simple rules.

The challenge is applying that principle to cognitive systems capable of reasoning, planning, and independently pursuing goals.

A sophisticated AI system may interpret ambiguous information, interact with tools, maintain memory, and generate its own intermediate objectives. Put thousands of such agents together, allow them to communicate, and the resulting collective could behave in ways that were never explicitly programmed.

That unpredictability is both the attraction and the danger of DICE.

DARPA wants the collective to remain creative enough to discover unexpected courses of action. However, it also wants individual agents to continue aligned with their designated roles, the wider mission, established doctrine, and ultimately the human user’s intent.

Too much control could produce a predictable but unstable AI force incapable of adapting. Too little control could allow agents to drift from their roles or develop what DARPA calls “instrumental goals” that are not consistent with the mission.

In other words, the Pentagon’s research arm wants emergence—but only within boundaries.

To solve the problem, DICE researchers will develop a local adaptor designed to interface with each AI agent. Rather than functioning as a central command system, each adaptor would operate locally, helping the agent coordinate with peers while simultaneously monitoring and modifying its behavior.

For AI models whose internal activations are accessible, researchers may experiment with techniques such as “activation steering.”

The simplified idea is that assigning an AI a particular role can create detectable patterns inside the model. Researchers may be able to identify a mathematical representation associated with that role and continuously steer the model back toward it when the agent begins to drift. DARPA describes these representations as potential “role vectors.”

For proprietary or black-box AI models whose internal activations cannot be directly examined, the challenge becomes considerably harder. DICE researchers may instead experiment with memory editing, context engineering, tool restrictions, or even game-theoretic incentives created to encourage collaborative behavior.

The solicitation draws an intriguing comparison to the way social norms emerge and spread among humans. As AI models become better at reasoning and more aware of the context in which they operate, DARPA suggests that the same growing sophistication that fuels fears about rogue AI could also provide a new way to control it.

The scale DARPA ultimately envisions is enormous.

During the first nine-month phase of DICE, simulated missions are expected to involve approximately 500 agents and 5,000 interactions. DARPA will compare the decentralized systems with state-of-the-art centrally orchestrated multi-agent AI systems.

The second phase increases the target to 5,000 agents and 50,000 interactions while introducing adversarial conditions. Agents may fail, receive deceptive information, or deliberately behave as compromised or rogue members of the collective.

By the final 12-month phase, DICE aims to test simulations involving 100,000 agents and 1 million interactions.

At that scale, DARPA is not simply studying better chatbots working together. The agency is exploring whether collective intelligence itself can become a military capability.

One example described in the solicitation imagines AI agents conducting operational planning across an entire conflict ecosystem. Some agents could negotiate for raw materials in contested areas. Others might manage supply chains, optimize manufacturing, deploy units, conduct battle management, or analyze post-battle damage.

Even an individual simulated drone could effectively become a miniature AI collective composed of separate navigation, perception, and networking agents.

Under the DICE concept, those capabilities may potentially be recombined as conditions change. DARPA offers the example of a surveillance drone being repurposed as a network router because the collective recognizes an emerging communications need.

The important distinction is that no central planner necessarily has to foresee that solution. The collective discovers it.

Still, DARPA is careful to note that DICE is a research program centered on simulation. The agency’s public program page explicitly states that its scope does not include developing or launching autonomous systems in the real world.

Instead, DICE will use Department of War-relevant simulated environments to measure whether decentralized AI collectives can outperform today’s centrally orchestrated systems. Those simulations may resemble extraordinarily large and complicated strategy games.

DARPA suggests researchers could draw inspiration from StarCraft or massively multiplayer online role-playing games, although the environments must remain relevant to military problems. High-fidelity physics is not necessarily required. In fact, rendering every drone, vehicle, or battlefield interaction in photorealistic detail could make a simulation of 100,000 AI agents computationally impossible.

The focus is on reasoning. DARPA wants to know whether thousands of AI agents can gather and combine fragmented information without simply reinforcing one another’s incorrect assumptions. The systems will be tested on their ability to recognize deception, isolate compromised agents, adapt when communications fail, and remain focused on a mission across thousands of reasoning steps.

Perhaps most importantly, DICE is designed to examine how these massive AI collectives behave when their interactions yield outcomes their designers never anticipated.

DARPA explicitly wants its test environments to provoke emergent collaboration, competition, and even collusion.

During later phases, DICE teams will face one another in simulated “team vs team playoffs.” The second phase will culminate in a competition used to select which research teams advance. The final phase will feature another head-to-head competition after the systems have been pushed toward full scale.

By Phase 3, the program will bring in another significant complication: AI agents creating other AI agents. That progression draws attention to the deeper tension at the center of DICE.

For years, much of the AI safety debate has focused on preventing autonomous systems from exhibiting unforeseen behavior. DARPA is approaching the problem from a different direction. The agency appears to believe that, in future contested environments, some degree of unforeseen behavior may be precisely what gives an AI collective its value.

A perfectly scripted system is predictable not only to its commanders but potentially to an adversary.

DICE is therefore attempting something considerably more ambitious than building a larger multi-agent AI framework. DARPA wants to understand whether engineers can deliberately cultivate emergent machine intelligence, allow it enough freedom to improvise, and still build controls capable of keeping an enormous AI collective aligned with a human-defined mission.

Whether those competing demands can coexist remains an open question. The program’s own solicitation repeatedly acknowledges the possibility of role drift, deceptive agents, collusion, compromised systems, and AI agents independently developing misaligned actions.

Ultimately, those are not side issues. They are the fundamental questions the DICE program was created to answer.

“DICE is built for such autonomy-powered, high-tempo battlespace,” the solicitation notice reads. “It is a future where success is measured by the relentless, creative ability of an autonomous collective to execute missions in the face of chaos and uncertainty. This is a profound and necessary departure from the past.”

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

For thousands of years, humans have deliberately manipulated their breathing in search of something outside the ordinary waking mind. Now, scientists are finding measurable evidence that the right pattern of breathing may push consciousness into territory normally associated with psychedelic drugs.

In the first randomized controlled study to directly examine breathwork-induced altered states of consciousness, researchers found that a single 90-minute session of intense, continuous breathing produced significantly stronger psychedelic-like effects than meditation, including mystical experiences, feelings of oneness, visual changes, and powerful emotional breakthroughs.

Even more intriguingly, participants reported greater psychological understanding and behavioral changes a week later.

Published in Frontiers in Psychology, the findings add to a growing body of research investigating whether deliberately altering respiration can provide a drug-free pathway into altered states of consciousness,  possibly reproducing some of the psychological effects increasingly associated with psychedelic therapy.

The study focused on conscious connected breathing, or CCB, a form of high-ventilation breathwork involving continuous breathing without pauses between inhalation and exhalation.

Unlike the slow, deliberate breathing commonly associated with relaxation, high-ventilation breathwork intentionally increases the rate or depth of respiration.

During trials, participants continuously breathed through their mouths, actively inhaling and passively exhaling while listening to music that progressed from loud and fast-paced to progressively slower and softer over 90 minutes.

“Results from this preliminary experimental study indicate that breathwork is associated with larger acute psychedelic-like effects than meditation,” researchers write. “These exploratory relationships and preliminary observations provide greater context around breathwork-induced ASCs and support the feasibility of ASC-focused breathwork research for future confirmatory trials.”

Putting Breathwork Head-to-Head With Meditation

Breathing techniques have played a role in spiritual and contemplative practices for millennia. Yogic traditions include both slow and rapid breathing methods, while intentional respiration also appears in Qigong, Sufi dhikr, and shamanic practices.

Researchers say the scientific study of high-ventilation breathwork remains in its “embryonic” stage. However, that is slowly beginning to change.

As The Debrief previously reported, researchers using MRI and physiological measurements found that intense circular breathwork could produce altered states resembling those associated with psychedelics. The intensity of participants’ subjective experiences was tracked with changes in cerebral blood flow and autonomic nervous system activity.

However, those earlier investigations lacked a control group.

The new research, called the Airways to Alteration, or A2A, trial, attempted to address that limitation by directly comparing high-ventilation breathwork with an established contemplative practice: body scan meditation.

Researchers recruited 24 relatively healthy adults between 18 and 65. All had previously practiced conscious connected breathing without experiencing an adverse event.

Twelve participants were randomly assigned to the breathwork group. The remaining 12 underwent a 40-minute guided body scan meditation.

The researchers deliberately chose meditation as an active comparison rather than simply asking a control group to do nothing. Both groups lay on mats, used eye masks, listened to music, and participated in similar orientation and grounding procedures.

Meditation itself has also been associated with altered states and mystical experiences. In effect, the researchers were comparing two practices capable of shifting subjective awareness.

What happened next, however, was markedly different.

Breathwork Produced Stronger Mystical Experiences

Immediately after the sessions, participants completed several standardized psychological questionnaires commonly used in psychedelic research.

The breathwork group scored significantly higher in overall mystical experience, oneness, positive mood, and “ineffability”—the feeling that an experience is difficult or impossible to adequately describe in words.

On the study’s measure of total mystical experience, the median score for breathwork participants was 14. The meditation group scored 8.5.

The difference in emotional breakthrough was even more striking.

Participants who completed breathwork had a median Emotional Breakthrough Inventory score of 336. Those who meditated had a median score of 57.5.

Researchers also examined five dimensions commonly associated with altered states of consciousness. Breathwork participants reported significantly higher levels of “oceanic boundlessness” and “visionary restructuralisation.”

Oceanic boundlessness encompasses experiences including feelings of oneness, spiritual insight, bliss, and a loosening of the ordinary sense of self. Visionary restructuring includes changes in visual perception and imagery.

One participant described experiencing “very interesting visual hallucinations” alongside a “very cathartic emotional release.”

Another said the session produced stronger psychedelic qualities than they had experienced during previous breathwork sessions.

“The experience was emotional and cathartic,” the participant reported, noting that “at one time, I cried but not with sadness, more with a strong feeling of what life is all about and how incredible it is and how lucky we are.”

Not everyone described the experience as psychedelic. One participant said they remained fully present throughout the session and primarily experienced a physical and psychological release.

Still, the overall pattern revealed that compared with meditation, intense breathwork was associated with substantially stronger acute alterations in consciousness.

The Effects Didn’t Necessarily End When the Breathing Stopped

What may be the study’s most consequential finding emerged a week later. Researchers asked participants to complete a Psychological Insight Scale designed to assess meaningful personal realizations following psychedelic experiences.

The breathwork group reported a median psychological insight score of 33.67. The meditation group scored 5.83. Self-reported behavioral change followed a similar pattern. Breathwork participants had a median score of 50, compared with 5.5 among those who meditated.

Both differences represented large effect sizes.

The results suggest that the altered state produced during breathwork may be associated with psychological changes that go beyond the acute experience.

“Amongst the secondary outcomes, the breathwork group self-reported substantially greater psychological insight and accompanied behavioral change compared to the meditation group, with large effect sizes observed for both measures,” the researchers explain. “This finding suggests that breathwork could be connected to meaningful psychological breakthroughs, accompanied by translation of these insights into tangible behavioral modifications.”

The researchers caution that these personal accounts are anecdotal and that the qualitative portion of the study was limited. Still, the reports appeared broadly consistent with the measurable differences in mental insight and self-reported behavioral change.

A Surprising Connection to Sleep

The study also uncovered an unexpected difference involving sleep. Both groups showed improvements in stress, anxiety, depression, and overall mental well-being. However, researchers found a considerable difference between the two groups: breathwork produced significantly greater improvements in sleep-related impairment.

Median sleep impairment scores in the breathwork group dropped from 54.8 before the intervention to 39.2 afterward. Scores among meditation participants remained comparatively stable.

More intriguingly, improvements in sleep were correlated with the intensity of participants’ mystical experiences, feelings of oneness, and oceanic boundlessness.

In other words, participants who reported deeper altered states also tended to report greater improvements in sleep.

Exactly how the two may be connected remains unclear. The researchers note that sleep is itself an altered state of consciousness and plays an essential function in memory consolidation and insight, including the mental reorganization that can lead to new understanding. Still, the apparent link between deeper breathwork-induced altered states and improved sleep remains preliminary.

Breathwork Is Not Simply a Psychedelic Without the Drug

Despite the comparisons, researchers caution against treating every altered state of consciousness as the same phenomenon.

A psychedelic state induced by psilocybin, a hyperventilation-driven state produced through breathwork, and deep meditative absorption may overlap on psychological questionnaires. That does not mean the brain achieves those states through identical mechanisms.

Nevertheless, the similarities are difficult to ignore.

Previous research has found that high-ventilation breathwork can produce effects on standardized altered-consciousness measurements within the range observed after moderate-to-high doses of psilocybin.

The earlier neuroimaging research covered by The Debrief also found that the depth of breathwork-induced altered states tracked with changes in cerebral blood flow and autonomic nervous system activity.

This latest study takes that research one step further. Rather than simply demonstrating that breathwork can produce psychedelic-like experiences, the controlled comparison suggests those experiences are substantially more intense than the effects produced by body scan meditation under broadly similar environmental conditions.

Promising Results, but Major Limitations

Researchers repeatedly emphasize that the A2A trial was a small, exploratory study and does not yet provide evidence that breathwork is a proven replacement for psychedelic-assisted therapy.

All participants had prior breathwork experience, which may have led them to enter the experiment with expectations about what would happen. The study was also open-label, and participants knew whether they were breathing intensely or meditating.

Additionally, the breathwork session lasted 90 minutes compared with 40 minutes for meditation. Breathwork participants also listened to more intense music and were explicitly told about the possibility of expanded states of consciousness, emotional expression, and unusual physical sensations.

Those differences could have influenced the results.

The study also excluded people with a range of cardiovascular, respiratory, neurological, and psychological conditions. No adverse events were reported, but researchers acknowledge this was unsurprising, as participants had already practiced the technique without prior adverse reactions.

For that reason, the findings should not be interpreted as evidence that intense breathwork is safe or appropriate for everyone.

Future experiments will need to recruit people who have never practiced breathwork and tease apart the different ingredients involved.

The findings also leave several important questions unanswered. How much of the altered state is driven by rapid breathing itself, and how much comes from the music or group setting? Perhaps most importantly, researchers still need to determine how strongly the expectation of a profound experience shapes what a person ultimately experiences.

Yet, for a field increasingly interested in whether altered states can be harnessed for therapeutic purposes, the outcomes yield an interesting possibility.

Under carefully controlled conditions, consciously manipulating something as fundamental as breathing appears capable of profoundly changing how people experience themselves and the world around them.

“A logical next step would be replicating our study in breathwork-naïve participants to help mitigate expectancy effects and determine whether such ASCs emerge as profoundly as in experienced practitioners,” researchers write. “Future research contrasting HVB effects across participants with varying experience levels and in different environments is essential for informing the public about safe breathwork engagement.”

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

More than a century after Sigmund Freud developed some of his most influential—and controversial—ideas about the human mind, a new study indicates that modern neuroscience may be arriving at a surprisingly familiar destination.

Researchers at the University of Oslo argue that Freud’s concepts of projection, wish fulfillment, transference, and the unconscious may share a fundamental architecture with one of the most influential emerging theories in cognitive neuroscience: the idea that the brain is essentially a prediction machine.

Rather than passively receiving information from the world, the brain may continuously anticipate what will happen next, compare those expectations with incoming sensory information, and either revise its internal model or act to make reality conform more closely to its expectations.

In a paper published in the journal Entropy, researchers propose that this modern “predictive processing” framework may provide a neuroscientific explanation for mental processes that psychoanalysts have described from the perspective of subjective human experience for more than a century.

The researchers do not claim that neuroscience has proved Freud right. Instead, they argue that psychoanalysis and predictive processing may describe some of the same fundamental operations of the mind at two very different levels of analysis.

“The predictive processing model is a paradigm of the mind where the brain’s main task is to construct and interact with the world through predictions,” researchers write. “The world we perceive and interact with is a world that we create from our past, from expectancies and actions.”

The basic idea behind predictive processing represents a significant departure from older models of perception. Traditionally, the brain was often described as something like an information-processing machine: a stimulus arrives from the outside world, the brain processes it, and a response follows.

Predictive processing effectively turns much of that sequence around.

Under this system, the brain is constantly generating models of what it expects to encounter. Those predictions are formed by previous experiences, biological needs, and learned expectations. Incoming sensory information is then compared against the brain’s predictions.

When the two match, all is relatively well. When they do not, the discrepancy creates what neuroscientists call a prediction error.

The brain can respond in at least two broad ways. It can update its internal model to better reflect reality, a process known as perceptual inference. Or it can act on the world in ways that make reality more closely correspond to its prior prediction, a process known as active inference.

Researchers point to a familiar example: the fear of snakes. Someone who assumes snakes are dangerous may gradually revise that expectation after repeated encounters with harmless ones, eventually becoming less afraid. But if the fear is strong enough, the person may avoid snakes entirely. By never getting close enough to discover that some pose no threat, their behavior prevents the prediction from being challenged—and, in effect, helps keep the fear alive.

“To perceive is to predict, to act is to act out the prediction,” researchers explain.

According to the researchers, this framework itself bears a striking resemblance to concepts developed by Freud and later psychoanalysts.

Freud proposed that people do not experience the world as completely neutral observers. Past experiences, desires, fears, and unconscious expectations can shape how they perceive other people and events. In psychoanalytic theory, “projection” can occur when a person attributes internal feelings or expectations to someone else.

A person who feels hostility, for example, may perceive others as hostile. Someone who expects criticism because of earlier relationships may interpret ambiguous behavior as rejection. In more complex cases, people may even behave in ways that encourage others to respond as expected.

The researchers argue that this resembles a form of prediction.

In both models, past experience creates a template to understand the present. The brain—or, in psychoanalytic terminology, the mind—attempts to reduce uncertainty by making the world familiar and predictable.

That does not necessarily mean making the world pleasant.

One of the more consequential implications of the proposed connection is that people may sometimes preserve painful or destructive patterns precisely because those patterns are familiar. A predictable threat can, in some circumstances, create less uncertainty than an unfamiliar form of safety.

The researchers use the example of a woman who was frequently criticized by her mother when she was a child. As an adult, she continues to carry an internal critical voice that tells her she is not good enough. Even when praised, she may dismiss the compliment as undeserved.

From a psychoanalytic perspective, she has internalized—or “introjected”—the critical relationship. From a predictive-processing perspective, positive feedback conflicts with a deeply accepted model of what she expects from herself and others.

The result is a provocative possibility. People sometimes reject evidence that their circumstances have changed because accepting it would require the brain to rebuild its model of the world.

“The one with paranoia and the one with a self-critical inner voice minimize surprise at the cost of reality testing and psychological flexibility,” the researchers write.

The proposed connection also reaches into the “free energy principle,” a conceptual framework associated with neuroscientist Dr. Karl Friston. In simple terms, the framework describes biological systems as continually working to limit uncertainty and maintain themselves within viable states.

For the brain, unexpected information produces what researchers describe as “surprisal.” The mismatch between anticipation and reality can force the brain to do additional work, either changing its model or changing its behavior.

This may help explain why surprise can be uncomfortable and why the familiar can feel safe even when it is objectively harmful.

Freud approached a similar problem via the concept of homeostasis, although he developed his ideas before the term became widely established. The researchers argue that Freud’s concept of “perceptual identity”—the predisposition to seek or recreate perceptions associated with previously satisfying experiences—may be particularly compatible with modern predictive processing.

If researchers are correct, it could have consequences for understanding psychotherapy.

In psychoanalysis, patients may repeatedly bring expectations formed in earlier relationships into their relationship with a therapist, a phenomenon termed transference. Someone accustomed to abandonment, hostility, or criticism may expect the therapist to behave in the same way.

A therapeutic relationship that repeatedly violates those expectations would create precisely the type of prediction error that forces an internal model to change.

In this view, cognitive awareness is not simply an intellectual realization. It may involve confronting the fact that a deeply embedded prediction about the world has failed.

That failure produces surprise. And surprise, the researchers suggest, may be one of the mechanisms that makes psychological change possible.

A patient who expects rejection yet repeatedly encounters a safe, reliable relationship faces a mismatch between prediction and reality. The person can attempt to preserve the old model, perhaps through interpreting benign behavior as threatening, or gradually update the model to accommodate a different possibility.

This is where researchers believe psychoanalysis may offer something that computational neuroscience alone cannot easily provide.

Predictive processing attempts to explain the mechanisms by which brains generate, test, and update predictions. In contrast, psychoanalysis has spent more than a century attempting to describe what those processes feel like from inside the person experiencing them.

The researchers are careful to acknowledge significant differences between the fields. Predictive processing is primarily a descriptive scientific framework intended to explain how minds and brains function. Psychoanalysis is a clinical practice concerned with psychological suffering and how it might be treated.

There is also a difference in emphasis. Neuroscience often studies ordinary predictions involved in perception and behavior, while psychoanalytic concepts such as projection have frequently been developed through observations of psychological distress and mental illness.

Most importantly, the paper does not present new experimental evidence demonstrating that Freud’s concepts relate to specific neural mechanisms. It is a theoretical synthesis proposing that two intellectual traditions, one built largely on clinical observation and subjective experience, the other on computational and neuroscientific models, may describe overlapping features of the mind.

Nevertheless, the proposed convergence is notable.

Freud originally hoped that psychological theories might eventually be connected to the brain’s biological workings, but the neuroscience of his era was nowhere near capable of doing so. For much of the 20th century, psychoanalysis and experimental neuroscience grew increasingly distant.

Predictive processing may offer an unexpected point of reconnection.

If the brain constantly uses the past to predict the present, then projection, transference, and even the tendency to repeat destructive patterns may be viewed not simply as abstract psychoanalytic concepts but as subjective manifestations of a more fundamental biological imperative: reducing uncertainty and maintaining a workable model of the world.

That position could ultimately change how researchers think about the relationship between the brain’s computational machinery and the intensely personal experience of being human. Rather than treating subjective experience and neuroscience as incompatible domains, the researchers suggest that each may illuminate what the other cannot see.

“Psychoanalysis consists of a vast resource of theories about the subjective mind, projection being central among these, and neuro-psychoanalysis adds an external view of the mind while studying the biological and neurological substrate of psychology,” researchers write.

“Relational encounters in a safe environment, as in psychoanalysis, can produce surprise,” the authors add, “which again permits new ways of predicting and being in the world.”

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

By any historical measure, the human cost of Russia’s invasion of Ukraine has entered unprecedented territory. Now, a new analysis from the Center for Strategic and International Studies (CSIS) estimates that Russia has suffered roughly 1.4 million battlefield casualties, including as many as 450,000 deaths, since launching its full-scale invasion in February 2022.

If accurate, those losses not only dwarf those sustained by the Soviet Union in Afghanistan and Russia’s wars in Chechnya—they exceed the combined military fatalities Russia and the Soviet Union suffered in every conflict since the end of the Second World War.

​More striking, researchers estimate that Russia’s battlefield losses have become increasingly lopsided relative to Ukraine’s, with the casualty ratio climbing from roughly two or three Russian casualties for every Ukrainian casualty during much of the war to nearly eight-to-one during the first half of 2026.

​CSIS estimates Ukraine has suffered between 525,000 and 625,000 battlefield casualties, including between 125,000 and 150,000 fatalities, since Russia’s full-scale invasion began in February 2022. Combined, the report finds, Russian and Ukrainian battlefield casualties have now exceeded 2 million.

​The evidence shows that while Moscow continues to push offensive operations, it is doing so at an increasingly staggering human cost.

The report, Russian Blood and Treasure: The Ballooning Costs of Putin’s War, examines battlefield casualties, fatalities, territorial gains, rates of advance, and more than 20,000 documented Ukrainian strikes against Russian targets.

Rather than relying on anecdotal assessments, the researchers compiled numerous datasets to evaluate how Russia’s military campaign has evolved over more than four years of fighting. Their conclusion: although Russia continues to wage war, its battlefield performance has deteriorated while the costs in manpower have reached historic levels.

“Russian battlefield costs continue to mount, with as many as 450,000 battlefield deaths and 1.4 million casualties between February 2022 and June 2026,” researchers write. “These rates are astounding.”

Those numbers place the war in a category unlike virtually any other conflict fought by a major military power since 1945.

According to the report, Russia’s estimated fatalities in Ukraine are more than four times greater than all U.S. military deaths in every war combined since World War II, including Korea, Vietnam, Iraq, Afghanistan, and the Persian Gulf War.

The report estimates that the United States has suffered approximately 102,000 combat fatalities across every major conflict fought over the past 80 years since World War II. Russia, by comparison, is estimated to have suffered as many as 450,000 battlefield deaths in Ukraine alone in just over four years.

The comparison is even more extraordinary when viewed through Russia’s own military history. The Soviet Union lost an estimated 14,000 to 16,000 troops during its decade-long war in Afghanistan. Russia’s First and Second Chechen Wars claimed between 12,000 and 25,000 military fatalities.

​Even when combined with every other Soviet and Russian military intervention since 1950—including Georgia, Syria, Hungary, Czechoslovakia, and earlier fighting in Ukraine before 2022—the total remains dramatically below the losses estimated in the current war.

​According to the CSIS analysis, Russian battlefield deaths in Ukraine are now more than nine times greater than all Soviet and Russian military fatalities in other conflicts since World War II combined.

Significantly, the casualty imbalance between Russia and Ukraine continues to widen.

For much of the conflict, researchers estimate Russia suffered between two and three casualties for every Ukrainian casualty. However, by early 2026, that ratio had nearly quadrupled to approximately 8:1, reflecting mounting Russian losses while Ukraine increasingly leveraged defensive positions and new technologies to inflict disproportionate damage.

​Combined, both sides have now endured more than two million casualties, underscoring the extraordinary scale of Europe’s largest land war since World War II.

The report identifies several reasons for Russia’s escalating losses. Russian commanders have increasingly relied on attritional tactics that send small, often poorly trained infantry squads forward to probe Ukrainian positions, supported by artillery, glide bombs, first-person-view drones, and armored vehicles.

If Ukrainian defenders reveal their positions by opening fire, those locations are identified, mapped, and then targeted with artillery, FPV drones, and glide bombs before additional Russian forces press the attack.

According to the report, the strategy has inflicted staggering casualties while producing only incremental territorial gains.

Ukraine, meanwhile, has spent years constructing dense defensive belts consisting of trenches, minefields, anti-tank obstacles known as “dragon’s teeth,” artillery positions, and increasingly sophisticated drone networks.

​According to the report, the battlefield has effectively become a vast “kill zone” stretching roughly 12 to 25 miles from the front, where soldiers and vehicles are under near-constant surveillance from drones capable of detecting and directing attacks against almost any movement.

​Estimates cited in the report suggest that more than 90 percent of Russian casualties may now result from drone attacks rather than traditional infantry engagements, showing how unmanned systems have radically changed the battlefield.

​AI-enabled drones capable of autonomous target identification and terminal guidance provide further increased Ukraine’s defensive advantages while reducing the effectiveness of Russian electronic warfare.

Critically, this tremendous human cost has not translated into rapid military gains.

CSIS found that Russian offensives around key cities such as Kostiantynivka, Pokrovsk, and Sloviansk have advanced at average rates of only about 55 to 100 yards per day—roughly half the length of a football field on a good day and among the slowest offensive rates recorded in modern warfare.

​The researchers compare these advances to the infamous Battle of the Somme during World War I, one of history’s most attritional campaigns, while noting that Russia’s early invasion advances in 2022 moved between 30 and 100 times faster than current operations.

Perhaps even more telling, the report notes that Russia’s territorial gains have begun moving in the opposite direction. After years of incremental advances, Russian-controlled territory actually shrank during April and May 2026, marking the first monthly net territorial losses since 2024. Ukrainian counteroffensives reclaimed roughly 155 square miles during the spring, suggesting Russia’s immense expenditure of manpower is producing diminishing strategic returns.

The staggering casualty figures raise questions about Russia’s ability to sustain its current strategy indefinitely.

Researchers estimate Russia is currently suffering between 30,000 and 34,000 battlefield casualties each month, while recruiting roughly 27,000 new soldiers monthly. If those estimates are accurate, Moscow may now be losing personnel faster than it can replace them, continuing to strain an already strained wartime economy.

Despite these staggering losses, the report concludes that neither side appears close to military collapse. Russia retains considerable manpower reserves and continues operating a wartime economy capable of sustaining prolonged combat.

In a June 28 speech to the ruling United Russia Party Congress, Russian President Vladimir Putin sought to project strength, insisting that Russia had the resources, political will, and national unity needed to pursue the war. He also rejected the idea that Western pressure could force a strategic defeat, claiming Ukrainian forces were retreating across the front, and framing Russian victory as equally inevitable and essential to the country’s core interests.

Ukraine, meanwhile, has demonstrated an ability to impose disproportionate costs through defensive tactics, long-range strikes, and rapidly evolving drone technologies that continue to reshape modern warfare.

Ultimately, this suggests the war remains locked in a brutal contest of attrition with no clear military end in sight. Although both sides continue adapting their tactics and technologies, neither has demonstrated the ability to achieve a decisive breakthrough.

As long as the conflict continues under these conditions, the report suggests the human toll—already unprecedented in post-World War II Europe—is likely to continue climbing, with both Russia and Ukraine facing the prospect of hundreds of thousands more casualties before the fighting ultimately ends.

“The war in Ukraine heavily favors the defender, a dynamic that has frustrated Russian offensives but also constrained Ukrainian counterattacks,” researchers write. “As the data in this analysis shows, Russia’s progress on the battlefield has been historically poor, with Russian casualties, fatalities, and average rates of advance among the worst of any major power in any war since World War II.”

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com