Research by psychologist Benjamin Converse at the University of Virginia finds that human beings tend believe in a kind of karma, namely our western skew on the spiritual axiom that good deeds result being treated well by fate; we believe we can influence uncontrollable outcomes by performing good deeds, with the often underlying expectation that the universe will pay us back in kind. Confronted with bad news, we may think "If I can get through this, I'll be a better person from hereon."
Karma is thus a kind of reciprocity: I'll buy this round, you'll buy the next, however the deal is made with the universe itself, rather than specific individuals. It's an attempt to steer life towards expected and advantageous directions. We hope our acts of kindness to pave the way for journeys through life that are safe and not too challenging; we hope our kind words inoculate us from pain and discomfort; alas, life doesn't comply with these demands.
Yet, as the Buddha taught in the first noble truth, aging, sickness and death are in store no matter how we behave, and so to will we experience a wide array of setbacks, separations and frustrations, often on a daily basis. While skillful actions can sometimes bring about positive external situations; just as often our generosity is not rewarded with validation or financial rewards. Meanwhile, truly vile and harmful individuals often achieve notable successes in the world; Dick Chaney and Henry Kissingers, for example, are very rich, criminal assholes (which is an insult to anuses, frankly).
And so when our best efforts result in lemons we may react by losing conviction in our spiritual paths. We turn nihilistic, feeling duped by spirituality, as if we've purchased a product that doesn't act as advertised. "Why did I bother helping so and so when they now don't return my calls?" is an all too common refrain.
The Buddha's teaching on karma, however, is not a promise of pleasure, acclaim or financial rewards for our skillful deeds. It's not even a promise of a good rebirth, or even that rebirth actually happens. Note the Buddha's great teaching to a people known as the Kalamas:
What if there is no life after death, if our actions, both right and wrong, have no external benefits? Still, here in our present lives, if we act without harmfulness or ill will, we will live in a state that is easeful, serene. -- Kalamas Sutta, Anguttara Nikaya, 3.65
In other words, if we act from generosity, good will, gratitude, we'll experience whatever life brings us with greater peace of mind; if we act aggressively, our psyches become agitated as result: no matter how wealthy we become, we wont truly enjoy it. Selfish and harmful acts result in feelings of lack of trust and connectedness with others, which is truly a dire state to find oneself in. I don't know how much misery Dick Chaney or Henry Kissinger experience, but I'm sure their internal realms would feel like hell to me.
Karma thus becomes intelligible and easy to understand once we understand that positive mind states, such as pride, confidence and inner esteem, arise from actions that connect us securely to others, whereas negative emotional states, such as shame, guilt, remorse and loneliness arise from actions that place us in competition with others. Happiness, in other words, arises less from accumulation or achievement, but from enacting a series of speech acts and behaviors that enhance our feelings of affinity and relatedness to others.
Human beings are pack animals; actions that benefit others, and integrate us into a community make us feel safe, and create what the psychologist Barbara Frederickson call "broaden and build" emotions: happiness, serenity, optimism. In Matthew Lieberman's clinical research, summarized in his book Social: Why Our Brains Are Wired to Connect, it is clear that the area of the brain that highlights emotional pain -- the anterior cingulate cruciate -- is principally activated by how well allied we feel with other people. In Robin Dunbar's work in anthropology and evolutionary psychology, summarized in his landmark text How Many Friends Does One Person Need? show that we are built to connect, which provides the foundation for peace of mind. In "A General Theory of Love" by psychologists Thomas Lewis and Fari Amini, it is established that human beings require secure connections to establish emotional stability and any sense of tranquility, for we rely on others for limbic regulation.
So karma is a psychological teaching, not a mechanical, Newtonian view. It demands that we take responsibility for the decisions we make, becoming accountable to both the harm or ease to others than can result, understanding that its our emotional states, not external conditions, that can be influenced. It's one of the great teachings in spiritual life: karma doesn't change our universe as much as it changes how we interpret and experience life. And how we experience life determines our happiness and peace of mind.
So, how would you like to proceed?