From biology to desire and action
How biological state becomes experienced value, motivation, decisions, reasons and interaction.
BERM treats the formation of motivation as part of the biological chain. Hormonal and neural state help determine what attracts attention, feels rewarding and seems worth the effort. Deliberation operates on those experienced values. The model therefore explains both what people are able to do and what they want, choose and give reasons for doing.
What enters this level
The receiving, endocrine and neural state described in Biology: hormone responsiveness, timing, energy, redox and electrical function. Their EMF-related change enters through the physical receiving bridge.
What carries forward
A distribution of initiatives, responses, choices and repeated actions. Interaction turns these individual outputs into relationships, population outcomes and the renewal of institutions.
State and experienced value
Changing biological state can change the weighting of reward and effort, and willingness to act, without a corresponding loss of ability.
An action has a possible benefit, a likelihood of success, an effort cost and consequences for oneself and others. The external situation supplies some of these quantities; biological state contributes to their experienced weight. A person can still perform a task while becoming less willing to choose it. Conversely, a particular immediate reward can become more compelling while sustained effort becomes less attractive.
Measured connections
Westbrook combined dopamine synthesis imaging and drug interventions in cognitive-effort choices; effects depended on baseline synthesis capacity. Jurgelis manipulated sleep in 24 participants and found greater aversion to cognitive effort while the short physical-effort comparison did not change in the same way. Draper’s randomized inflammatory challenge reduced acceptance of high-effort options without a corresponding significant change in reward sensitivity. Westbrook 2020i; Jurgelis 2022i; Draper 2018i.
What BERM draws from this
BERM explains changes in experienced priorities through measurable biological states. The same amount of time, money or effort can acquire a different weight. Stated lack of resources can therefore combine a real constraint with altered valuation. The parsimonious target is the joint pattern across choices, using shared state variables and task-specific consequences.
Desire, attachment and care
Biological regulation of the reproductive axis participates in sexual motivation and neural processing of sexual stimuli.
Motivation to approach, readiness to respond, sexual arousal, attachment, wanting a child and caring for another organism are related outputs with different functions. Reproduction requires both opportunity and functional transitions. BERM accordingly includes the biological formation of initiative and responsiveness alongside the capacity to conceive and maintain a pregnancy.
Measured connections
Finkelstein’s gonadal-suppression and hormone-replacement experiments separated testosterone and estradiol contributions to male sexual function. In Mills’s crossover trial, 32 men with low sexual desire completed both kisspeptin and placebo conditions; sexual-stimulus brain responses and penile tumescence changed without a significant measured testosterone change. The maximum tumescence increase was a physiological measure, not a percentage increase in desire. Finkelstein 2013i; Mills 2023i.
What BERM draws from this
The reproductive pathway has two coupled branches: whether an attempt occurs, and whether it succeeds. A biological shift can reach both. Desire for a child and a concrete attempt need their own observations and transition rules; the model can then explain how motivation, partner response, age and physiological capacity combine over time.
Reproductive regulation · behaviour · feedback
From felt motivation to realised reproduction
Animal interventions show selective changes in reproductive interest; human hormone interventions locate sexual responses and target-specific endocrine gates. BERM follows desire into approach, the other person’s response and an actual encounter. The biological success of that encounter remains a separate branch, alongside caregiving and its feedback.
Follow the three branches and their evidenceCalcium · redox · hormone production
Production capacity continues into motivation and action
Autophagy links cellular maintenance to cholesterol availability and steroid production, including in human ovarian and testicular tissue. A randomized testosterone trial in older men with low testosterone and low desire connects hormone intervention to sexual activity and desire.
BERM carries hormone production through tissue response, motivation, opportunities and reproductive function. The trial’s age and hormone context stay attached to its finding.
Explore the shared mechanism and its studiesTime and learning
Biological state changes feedback-learning weights and choice consistency, so a transient state can influence later action through learning.
The organism’s state affects the choice made today and the history from which tomorrow’s choices are learned. A reward, failure or social encounter can update expectations with a different weight under different states. Learned routines and changed opportunities can then carry an effect beyond the initial physiological episode.
Measured connections
Lim compared a week of restricted sleep with a rested condition and found altered positive-feedback learning and more stochastic choices despite similar overall accuracy. Westbrook’s later dopamine study connects biological intervention to learning and effort-related choice within the broader RADBOUD-DA research program. Its 2020 and 2025 publications provide connected outcomes, not automatically independent replications. Lim 2026i; Westbrook 2025i.
What BERM draws from this
BERM carries state into the learning operator. The later persistence of a behavioral pattern can reside in learned values, a missed encounter or a changed relationship. An acute hormone change does not have to remain physically unchanged for years to have a lasting consequence.
L is the accumulated learning state, feedback is the experienced outcome and S is the biological state during updating. The equation specifies a model connection; its parameters are estimated for the actual task and data.
Decisions and reasons
An expressed reason is an observation of the decision process and can also be produced for an unnoticed change of choice outcome; it does not by itself identify motivation’s causal origin.
A person reasons from what appears desirable, feasible, threatening or costly. If biology changes those weights, a coherent explanation can change with them. The experienced reason is itself part of the event to explain. BERM therefore follows state into valuation, deliberation, action and the account a person gives of that action.
Measured connections
Johansson covertly changed the outcome of a face choice; participants sometimes justified the substituted outcome without detecting the mismatch. Eisenegger randomized testosterone administration and measured participants’ later beliefs about the administered substance. Drug assignment and reported belief showed different associations with offers; only drug assignment was randomized. Johansson 2005i; Eisenegger 2010i.
What BERM draws from this
An articulate explanation is not automatically an independent upstream cause. It can express a biologically shifted motivation and can subsequently become a remembered commitment or guide for action. Deliberation and learning remain functions of the biological system. This structure does not require every reason to be post hoc or every external constraint to be imagined.
From individuals to joint action
A biological intervention directed at one interaction partner can change the other partner’s behavior and physiological responses during their interaction.
Joint action needs initiative, a responding partner and temporal overlap. A change in either person alters the pair’s probability of success. Across a population, small changes can accumulate through repeated encounters and thresholds: who meets, who responds, which cooperation succeeds and which relationships continue.
Measured connections
Weisman administered oxytocin to fathers and measured father–infant interaction; changes appeared in infant behavior and physiological responses as well as in fathers. In a separate school-network experiment, Paluck showed that the placement of participating students in the network mattered for changes in community conflict reports. The first study locates an acute interpersonal transition; the second locates propagation through a social network. Weisman 2012i; Paluck 2016i.
What BERM draws from this
A biologically changed action becomes part of another organism’s input. Repeated across a network, this creates changes in the distribution of opportunities and actions. Institutions persist through those actions and their stored consequences; their rules and technologies feed back into later biological and material environments.
Synthetic timing example
Joint action needs two compatible windows
Two fictional people have equally long periods of availability. Shift person B’s window to explore the timing opportunity for a shared task.
Original timing: 0
Shared time: 4 time units. Shared interval: 9–13.
The overlap is a timing opportunity in this example. It is not a reproduction percentage, a probability of actual action or a prediction of an EMF effect.
Opportunity to encounter
Both have time together. Goals, willingness and consent are separate conditions.
Measurable event
Record an initiative, a response and an actual shared task. A time window does not yet tell us what people do.
Outcome to follow
Follow repetition and the interaction network. One pair does not represent population or institutional change.
What does this example calculate, and what is measured next?
Calculation: max(0, min(end A, end B) − max(start A, start B)). A spans 5–13 and B initially spans 9–17. The control shifts only B; both durations stay at eight. The scale does not represent a particular species’ days or a human circadian rhythm.
Moving from an individual to a pair and a wider group requires records of encounters, choices, repetition and networks. Hormones, motivation and population outcomes are not calculated from this time window.
In BERM’s conditional chain, a timing change could enter through a specified receiver response. This illustration begins with two assumed time windows: the shift is neither derived from a field nor calibrated with biological data.
From individuals to joint action: studies and the BERM interpretation →One state, several connected consequences
BERM derives physiological and behavioral outputs from a shared time-dependent biological state; the field-to-state coupling is the separately specified upstream step of the chain.
This proposed BERM composition separates success probability p, experienced benefit B, effort E, harm H and external cost C. Their weights depend on biological state S; L denotes learning history. Choice probabilities depend on the resulting values V. Shared states constrain several outputs together; the expressions become quantitative only when their variables and coefficients are tied to a particular dataset.
For an intentional reproductive attempt, birth probability composes initiation, conception conditional on the attempt, and live birth conditional on conception. The chain uses conditional probabilities rather than an independence assumption. Total births also include pregnancies that begin without an intentional attempt. Pair distributions and the life-course calendar carry both branches into population outcomes.
Explore the connected explanations
Reproductive regulation
Motivation, physiological capacity and caregiving, joined through measured biological and social transitions.
Brain mechanisms
The receptor, electrical and chemical systems behind the behavioral continuation.
State and coordination
Hormone responsiveness, tissue timing and the history of the receiving system.
Reproductive transitions
From functional gates to couples, waiting times and realised births.
How the studies connect
Seven research connections from reception to valuation and collective outcomes.
The biological individual
Read the existing individual-level civilization essay alongside this mechanism.
Behavior across organisms
The parallel route through mating, pollination and ecological interaction.
Continue the explanation
From actions to civilization
Follow individual distributions through pairs, networks, populations, institutions and historical feedback.
Social action
Neuromodulation and a nutritional intervention change the weights of measured social choices, including harm avoidance and rejection of unfair offers.
Cooperation, withdrawal, fairness and care require organisms to value outcomes for themselves and others. A social endpoint therefore continues the biological explanation. The next question is which decision weight changed, in which setting, and how the resulting action changes another person’s environment.
Measured connections
Crockett’s two randomized drug experiments changed how money was weighed against pain to oneself or another person: serotonergic and dopaminergic interventions produced different patterns. Strang’s randomized crossover breakfast study changed costly rejection of unfair offers. Tyrosine was a measured candidate mediator, not separately randomized. Ben Simon’s sleep study connected sleep loss to willingness to help; its donation analysis used a separate aggregate dataset. Crockett 2015 ↗iDissociable Effects of Serotonin and Dopamine on the Valuation of Harm in Moral Decision MakingCurrent biology : CB · 2015 · journalMetadata matched; Strang 2017 ↗iImpact of nutrition on social decision makingProceedings of the National Academy of Sciences of the United States of America · 2017 · journalMetadata matched; Ben Simon 2022 ↗iSleep loss leads to the withdrawal of human helping across individuals, groups, and large-scale societiesPLoS biology · 2022 · journalMetadata matched.
What BERM draws from this
Biological state contributes to social preferences through concrete choices. To reach institutions, BERM composes those choices across people, networks and repeated time steps. The intermediate quantities are participation, effort, trust-bearing actions, sanctioning and withdrawal, each attached to a measured or explicitly modeled outcome.