Ethan talks a lot about interdependence at what might be called the macro level, for example, in terms of food production and consumption. So what’s the micro level?
Have you ever noticed that people pick up the attitudes, preferences and habits of the people with whom they spend a lot of time, or with whom they are emotionally connected? Some examples:
*Your best friend loves Bruce Springsteen. You cringe at the opening notes to “Born in the USA.”  After a few years, you decide that your friend is right. The Boss is a genius.
* An American who lives in London for a year not only picks up a bit of an accent but also starts reporting the time differently—“half three” instead of three thirty. She is unaware that she is doing this until American friends point it out.
*Your grandmother is a master gardener. You don’t know a trowel from a shovel. But when she passes away you develop an overwhelming need to take up gardening, and find that it brings you great joy.
*You have a coworker who manages to “keep on the sunny side.” No matter what happens, she remains steadfast in her positive, constructive approach to life. You find that when you are around her you feel a little more optimistic than you do otherwise.
*You wake up in a good mood and get ready to start your day. As you leave the house, you find yourself stuck in a traffic jam. People are honking, shouting, flipping each other off, driving erratically. By the time you arrive at work, you are anxious and irritable.
Do we have any thoughts or feelings that are entirely independent of other people? Is our subjective impression of the world actually subjective?

These are somewhat simple examples. But the phenomenon itself is complex and pervasive. Ethan likes to define interdependence by saying, “nothing happens in a vacuum.” This includes our thoughts and perceptions and emotions. You don’t perceive a given car separate from the car you own, the one you wished you owned, or the car your parents owned when you were five. When you watch a movie, you don’t somehow forget every other film you’ve seen. You evaluate it in part based on other films you’ve seen, your ideas and expectations about that film, and about films in general, and on the reactions of those who are watching the film along with you.
For me, the most fascinating way to contemplate interdependence is at the level of intimate one-on-one interaction in the present moment. If you think about the people you are close to—family, friends, lovers—you may feel that you are a slightly different person with each of them, or perhaps that you express a different part of yourself with each of them. The reason for this may be due in part to what Daniel Stern, MD, calls “the intersubjective matrix.” In a moment of interaction, you are taking in a lot of information about the other person through body language, voice tone, etc. The things you think, say and do in that moment are affected by that information. Your perceptions shape your social interactions, and those interactions in turn shape your perceptions. So it isn’t only that each person resonates with you a little differently. It is that over time the two of you co-create your relationship to each other, such as it is, and that relationship in turn changes you both. You then take that changed person into your other relationships.
We know this already, of course, because we know people whose adult relationships are still negatively affected by early relationships with their parents or other caretakers. But what we don’t seem to think about as often is the extent to which our lives are continually influenced by our daily interactions with people: coworkers, neighbors, friends, or even online communities. The influence can be obvious but also subtle. You may find yourself walking down the street smiling without really knowing why, or you may find that your stress level is higher than normal without really knowing why. You may develop different preferences as a result of those relationships. Ideally our meditation practice helps us to be more in touch with our true selves so that we can better identify feelings and their causes, but even then it is still very difficult to attribute cause and effect, because the reasons are so multi-faceted, and because we tend to underestimate the influence the people in our daily lives have on our mind and emotions.
In the world of science, there was a time when the “nature vs. nurture” debate was popular. Is a given disease or psychopathology a result of genetic makeup, or of a person’s environment? We have learned that in almost every situation, the answer is both. We know this primarily from studies of identical twins: instances in which two people with identical genetic materials are followed for a given period of time, and one develops a condition while the other does not, even though they were raised in the same family. Science is still trying to make sense of how that happens, but the take home message seems clear to me: at every level of existence, our reality is a combination of who we are and the accumulated experiences and interactions of our lives.
Buddhism tells us that the fundamental cause of suffering is lack of awareness of our fundamental interconnectedness. There is plenty scientific data out there suggesting that our very existence as living beings depends on having healthy and supportive bonds with other people. Developing brains require feedback from others in order to function properly—this goes for the brains of kittens, monkeys, human babies, etc. Many of you may be familiar with the attachment theories popularized by John Bowlby, or on the earlier famous experiments by Harry Harlow, in which baby monkeys were given the choice of two inanimate “surrogate mothers,” both of which offered food. One was made of wire mesh and the other of soft terry cloth. Baby monkeys who had a comfortable terry cloth “mother” to cuddle to received some emotional comfort from frightening situations. Those who only had a cold wire mesh “mother” demonstrated severe terror and anxiety when frightened. Monkeys who were entirely deprived of mothering for the first eight months of their lives suffered permanent damage.
Attachment is one aspect of intersubjectivity. But what I’m talking about is even more basic. Our thoughts and feelings are co-created by the thoughts and feelings of other people. Babies left in solitary confinement will die even if given food and water. Adults left in solitary confinement will go mad. Our brains aren’t made to operate that way. They simply cannot function properly in isolation. Our very sense of ourselves as individuals is a construct. Even the most adamant loner is defining him or herself as such in relation to the people around him or her, and even that loner has a deep-seated need to feel seen and understood by somebody.
It is an overwhelming thing to contemplate. Where do I end, where do you begin? Do I have any feelings and perceptions that are entirely my own? What do I do with this idea of intersubjectivity, this fact of the interdependent nature of my existence even at the level of consciousness? For me, it leads to even greater motivation to become awake and aware, to get out of my own head, to develop compassion, to be kind, to choose my friends wisely, and to avoid situations that are harmful to others or myself.
If you are interested in reading more about these ideas, I highly recommend checking out:
Daniel Stern, MD, The Present Moment in Psychotherapy and Everyday Life, chapters 5-8
Daniel Goleman, Social Intelligence: The New Science of Human Relationships