In 1967, polygrapher Cleve Backster connected electrodes to a house plant to measure psychogalvanic reflex (PGR)—how quickly moisture increased in the plant after it was watered. During the experiment, he became curious about what else the equipment might measure. For instance, could it detect the plant’s stress levels?

He dunked a leaf in a cup of hot coffee. Nothing. He pondered what to try next. Aha! he thought. I’ll burn the leaf. The instant the thought leapt into his mind, the needle on the machine jumped—just as it would for a human experiencing sudden stress. The plant seemed to sense Backster’s diabolical plan … and it was afraid.

Sound crazy? Maybe. But Backster was no quack. He began his career as an interrogation specialist with the CIA and went on to become Chairman of the Academy of Scientific Interrogation’s Research and Instrument Committee. And he wasn’t the first to believe plants might be sensitive.

In All I Really Need to Know I Learned in Kindergarten, Robert Fulghum relates the story of unique logging rituals in the Solomon Islands. When it’s time to prune unwanted trees, the loggers lay aside their cutting tools. For 30 consecutive days, they creep up on the trees at dawn and scream at them in rage. When the 30 days end, the trees drop dead.

If evil thoughts and hateful words cause plants to wither and die, imagine what they do to a human spirit that fully understands their meaning. Good enough reason to spend our time offering kindness and encouragement.

“That best portion of a good man’s life; His little, nameless, unremembered acts of kindness and of love.”

—William Wordsworth, poet

“No act of kindness, no matter how small, is ever wasted.”

—Aesop, fabulist

“Kindness is a language the [mute] can speak and the deaf can hear and understand.”

—Christian Nevell Bovee, author and lawyer

“I expect to pass through this world but once. Any good therefore that I can do, or any kindness that I can show to any fellow creature, let me do it now. Let me not defer or neglect it, for I shall not pass this way again.”

—William Penn, religious leader and founder of Pennsylvania

“Kindness is more than deeds. It is an attitude, an expression, a look, a touch. It is anything that lifts another person.”

—C. Neil Strait, pastor

“Let no one ever come to you without leaving better and happier. Be the living expression of God’s kindness: kindness in your face, kindness in your eyes, kindness in your smile.”

—Mother Teresa, missionary and humanitarian

“If everyone received the encouragement they need to grow, the genius in most everyone would blossom and the world would produce abundance beyond the wildest dreams. We would have more than one Einstein, Edison, Schweitzer, Mother Theresa, Dr. Salk, and other great minds in a century.”

—Sidney Madwed, author and poet

“What sunshine is to flowers, smiles are to humanity. These are but trifles, to be sure; but, scattered along life’s pathway, the good they do is inconceivable.”

—Joseph Addison, essayist and statesman