What is Love?  the pinnacle of Biochemistry!

He who knows nothing, loves nothing.
He who can do nothing understands nothing.
He who understands nothing is worthless.
But he who understands also loves, notices, sees....
The more knowledge is inherent in a thing, the greater the love...
Anyone who imagines that all fruits ripen at the same time as the strawberries knows nothing about grapes.

Paracelsus, physician & chemist of the 16th century


(If you were hoping to find here a discussion about romance and that biochemistry, click on either link in this sentence.  Or you might want to read what is below first, then proceed to consider romance after doing so.)

Galen of Pergamum (b 129AD, d ~200 or 216) was the Greek physician whose theories dominated Western medical science for well over a millennium and still influences some of our conceptions.  He suggested that while rational thought resides in our brain, our emotional soul is in our hearts.  We still exchange Valentine's hearts to express our love.  So it may be a challenge to think of the brain as controlling love.  It may be even harder to consider love as something which can be learned.  And it may be most difficult to think of love as a biochemical process which can be taught!

Much previous has been written of love.  Some of our difficulty is rooted in our use of the term love to specify a wide variety of different feelings, motivations and activities.  The ancient Greeks distinguished three types of loving relationships:
eros: an affectionate madness involving sèxûal plèasure
philia: a fondness denoting either brotherhood or generally non-sexual affection and concern such as for siblings
agape: unconditional, self-sacrificing, active, volitional, knowledgeable and thoughtful love.
This essay starts with a concept close to that of agape and the following web page broadens the discussion to all three.

One of the problems is that we usually define love in ways that make it difficult to investigate with the tools of science.  An alternate definition follows below which closely matches what is usually meant by agape love, but potentially provides understanding in terms of the structure and chemical reactions in one's brain.  By understanding how love develops, love might be effectively taught (Read Early learning: to Learn & to Love), later difficulties understood and perhaps corrected.  The intent here is to provide a rudimentary hypothesis based on current understanding of learning which might later be corrected and improved as new experiments and observations require.

Love is an art where one finds joy despite ones action itself providing no pleasure for oneself.

Defining love as an action which provides pleasure brings love into the realm of activities which have been experimentally studied and understood in terms of biochemical reactions largely within the brain.  But to distinguish love from other pleasurable experiences, the requirement is added that the experience on its own merits would provide no direct pleasure or reward, but rather often suffers some degree of discomfort, even pain.  This could be in part because the action is not routine, customary or condoned as tradition, or like a good turn, just requires that one goes out of their way.

Generally pain and discomfort are the result of stimuli to the nervous system which encourage the individual to stop the action or withdraw from the cause of the stimuli.  This also provides learning to avoid repeating the action in the future.  Such pain provides a mechanism which serves to protect the individual from potential harm such as a temperature extreme, harmful chemical, or destructive movement or force.  This is accomplished in the brain by chemical reactions within neurons (nerve cells) and in exchanges of neurotransmitter molecules and new cell growth at synapse (the junctions between neurons which store data from a related experiences).  For example, a synapse of a nerve receiving the message of a painful burn creates short term memory by releasing neurotransmitter molecules across the existing synapse.  But repeat or extended experiences where another neuron stores visual information of a burning match develops long term memory by growing a new connecting synapse associating the pain with the visual information, thus help avoid a future repetition.  (See Biochemistry 7: Memory for diagrams and explanations in greater detail.)

By superficial analysis, it might appear that the above proposed definition for love often involving a negative stimuli would result in learning to avoid future acts of love.  But love apparently involves a more complex process.

Synapse also grow linking neutral information from our senses with those involving positive rewards.  Children, from birth, begin to learn to associate the receipt and taste of nourishing milk with other contemporary nerve information such as the warmth and pressure of being held and cuddled.  Later visual and auditory information is also linked so that a baby recognizes the parent who provides the food.

Months later an infant learns to recognize facial expressions and vocal sounds as carrying distinct messages which are initially associated with receiving food and the cuddling now associated with the food.  Other sounds and visual images may begin to be associated with discomfort and even pain.  Gradually an infant learns to distinguish more subtle differences.  But equally important, chains of synaptic connections form so that a child's brain eventually will know that a language question about hunger is indirectly associated with the potential of receiving food.  By developing long chains of synapse connections, words such as yes and good become distinct from no and bad.

This same mechanism of linked synapse is eventually used to learn that some actions which provide satisfaction and pleasure in others are good even though they may bring temporary discomfort to the individual providing the action.  For example, learning to behave properly often means that the individual must forego their own immediate fun and pleasure, but could eventually result in delayed reward or the absence of eventual pain or other punishment.  This provides the mechanism of how love is learned.  The individual denies or delays immediate personal pleasure to instead try to provide benefit for another person.  The brain still obtains a vicarious pleasure through the chain of synaptic links back to the original receipt of nourishment, while in reality a direct reward may often be missing.  The neurotransmitter still provide the equivalent of a chemical reward certificate for brain synapse, even though there is often no direct inflow of any positive reward from the senses.  The individual's act of love often may produce some personal discomfort or even occasional pain.  But the vicarious, learned chain of associations provides the reward needed to establish and maintain such acts of love.

occasional strange consequences

Sometimes this mechanism for learning to love produces strange or undesirable consequences.

If children spend significant time playing video games (or other activities) where they gain a reward or game provided pleasure for acts of violence or destruction, and they fail to receive stronger learned associations for more appropriate social interactions from parents and those around them, they might have an inclination to use violence or destruction to solve problems when older.  In short, it may be wise to monitor and consider what sort of synaptic associations are likely being developed in young children to make sure that they learn to love and to behave in socially acceptable ways when faced with problems in teenage years and adulthood.

A portion of the population apparently learns to enjoy personal pain.  Likely financial hardship pushes some people to do so, but others voluntarily submitting themselves to torture, prostitution and other denigrating experiences.  Many people developing a healthy ability to love which includes an empathy of what actions will likely provide for the needs and pleasure of others.  But others appear to have developed chains of synaptic links which provide sufficient vicariously pleasure when receiving pain for them to directly desire pain for themselves!

some tests for love

The following classical teenage challenge of his date may be a true test of her love: If you love me, you will have sex with me!  But the classical response may be an equal test of love: If you love me, you will wait until we marry! But for these to be true tests of love, the date must have not shared the wish.  If they both want the pleasure of immediate sex or wish to wait until marriage, the test fails the condition that they otherwise would not have had.  One is not acting out of love for the other to do what one wants for one's self.  In the traditional definitions of love, the emphasis is that love is an act of giving rather than getting.  Love occurs when a person foregoes what one would want for their own pleasure, substituting instead what the other person desires or needs.  With a little thought, countless other tests of love can be formulated, most of which are much less harsh than these two.

While determining whether one is acting out of love or not may be largely a semantic exercise, there may be value in defining love in such a way that it can provide tests for whether we have learned to love in ways that are socially acceptable and conducive for forming and maintaining optimum relationships with others.


We have a mechanism in which new connections develop between the synapse at neuron ends in our brains in response to stimuli our bodies receive.  These links both provide long term memory and associations.  We use these associations to learn cause-effect relationships in nature, to learn the meaning of language and non-verbal communication, and to feel satisfaction and pleasure for experiences and actions which don't directly carry their own reward.  These grown physical connections between nerves in the brain also provide us a mechanism to act out of love for another, foregoing what may be in our own immediate interest or pleasure.  The same mechanism which is involved in all learning including learning to be loving, can also result in learning less desirable behaviors.  So it would seem appropriate to give considerable attention to how infants and young children are taught so that they mature into healthy, happy, productive individuals.

to the next page: Romance



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Early learning learn & to Love
Biochemistry 6: Brain Chemstry
Biochemistry 7: Memory
Biochemistry 10: Mating

created 27 February 2008
latest revision 4 April 2008
by D Trapp
Mac made