Hurtful words in a relationship can be like a drop of red dye in a glass of water that turns the whole glass pink. What starts out as a slip of tongue, a small slight from one person to another, sets a process in motion that slowly (or quickly) permeates a relationship and begins to define its tone.

It's easy to think criticism is a constructive process -- one member of a relationship feels that they know the other in and out, and in making "suggestions" for how they might change or improve, they are merely helping them overcome their flaws and deficiencies. "You're a handsome man," she might say, "but wouldn't you rather wear a dress shirt than those ratty T-shirts?" He might say "You're always blabbing to your friends on the phone, you should be quiet -- read a book or something." Sometimes this works. Perhaps the other person abides the advice and adjusts the behavior to make you happy. Other times this doesn't work: "If she doesn't like my clothes, I'm going to wear the outfits she hates most."

Criticism may not always take the form of words. It can be a touch, a glare, an eye roll, or two hands thrown up in the air. However it comes out, the message is that one person is superior and the other inferior. One person is up, the other person is down. It's an unpleasant feeling for the person down, a feeling that has its roots in the animal-like parts of our brain, sometimes referred to as our "lizard brain." Harsh words can induce a feeling of anxiety. Anxiety, at its roots, is the nervous system responding to a stimulus of danger -- the fight or flight response. The response of the criticized person also takes one of these forms: They may slink away, play dead in a submissive posture, or take on the accuser by fighting back.

Whether criticism is phrased in a gentle way or a cruel way, it comes from the same place of judgment. Unconsciously, the critic believes that their opinion is the "only" correct one. The way he or she looks at the world is the only reasonable way to see it, and if the partner, on some level, differs, they must have no sense, or taste -- in fact, they're crazy! The other person, in a way, ceases to be a person, and is instead an object to be molded into the critic's (sane) way of looking at the world.

That said, a relationship without dialogue, without one person being able to express a concern, is also an unhealthy place. Suppressed thoughts and feelings lead to passive-aggressive behavior, or to the gradual dissolution of affection for one another.

The path out of this relational trap is to first take on an approach of zero negativity: for both parties to commit absolutely to refraining from put downs, negative comments and behaviors. It's imperative that both members of a couple make a strict commitment to this approach. Not just temporarily, but always. In a particularly unhealthy relationship, this might in fact mean that both people have nothing to say to each other for a long period of time. In this case, the dynamic between the partners has become so toxic, so stuck in a loop of one-up, one-down behavior that it's violated both members' feelings of trust and safety.

Ultimately, though, all committed relationships contain a seed, no matter how small it may seem, of meaningful love and affection. Even if the approach of zero negativity leads to, essentially, a vow of silence, eventually the mantle of fear will dissipate and both parties will find the warmth toward each other that they once had. They will find things to say that are neutral and eventually positive. As the activated fear in the lizard brain diminishes, both people will begin to feel safe with one another, which is the primary and most important foundation of a healthy relationship.

The zero negativity approach doesn't imply that partners shouldn't be allowed to express concerns or desires for behavioral change in a relationship. It's all about the way it's presented. A hurtful comment out of nowhere or passive-aggressive put down is unacceptable. But one phrased carefully and delicately can lead to the desired effect.

One way to frame a safe conversation is to start with a statement like "I'm having a hard time with something, and I want to share it with you. Is now a good time to talk?" If it's not a good time for the other person to hear this, the requester must accept it. But the other person must in turn offer a time he or she would be more open to hearing your concerns. Knowing that you are going to express something critical takes away the element of surprise and defensiveness in the other person, and allows you to state your concern in a thought out, gentle way. It makes it much more likely that they will be willing to compromise and come closer to your side of the fence.

This is the second step in creating a healthy, constructive environment for change. But again, the very first step is zero negativity. It's a rule that's easy to remember but may be difficult to follow at first. In time, you'll begin to notice all the ways you were being unconsciously critical -- making jokes at the other's expense, speaking negatively about them to others, thinking passive aggressive thoughts. This awareness itself can motivate change.

I challenge you to give it a try -- not a word, not a comment, not a glance in a negative direction. It may just take you from zero to 60.