Recently, I’ve been thinking about a very interesting social phenomenon, and I wonder if you’ve ever experienced it. You’re especially attentive to friends or colleagues, helping out a lot. At first, they’re extremely grateful, but gradually they start taking your efforts for granted. What’s more awkward is, when you’re unable to help once, you’re instead criticized, as if you’ve changed your mind. Honestly, I’ve fallen into this trap myself — during that time, I really wanted to be the “good guy,” but I found that gratitude didn’t increase, and expectations only grew higher.

Actually, there’s a psychological principle behind this called the Law of Habituation, which is quite obscure but really practical. Simply put: people are initially very sensitive to certain stimuli and respond strongly, but if the same stimulus repeats too often, the brain automatically “gets used to it,” and the response weakens over time. It’s like receiving a gift from a friend for the first time makes you very happy; the second time might still touch you, but after many times, it feels less special. This isn’t human indifference, but a self-protection mechanism of our brain — cognitive resources are limited, and we can’t be equally sensitive to all good things.

From a neuroscience perspective, it’s even more interesting. Good things initially release a large amount of dopamine, making you excited and happy, but the brain quickly learns to predict these good experiences, so the actual thrill diminishes. This also explains why the honeymoon phase always passes, and doing the same thing afterward feels less exciting. In economics, there’s a similar concept called diminishing marginal returns — the same investment initially yields high returns, but as you add more, the stimulation from the gains gradually decreases.

Psychologist Babb conducted a classic experiment: when people hold a 400-gram weight and then switch to 405 grams, most can immediately feel the difference. But if the first weight is 4000 grams and only 5 grams are added, almost no one can tell the difference. In 2016, the British Psychological Society published an experiment where participants received small favors at different frequencies every day. The result was that the novelty of frequent rewards quickly disappeared, whereas reducing the frequency made people cherish and remember the favors more. It’s a chilling realization — sometimes less really is more.

So, how to reverse this “marginal diminishing effect of giving”? First, deliberately control the frequency of your efforts, making kindness scarce. Don’t give everything at once from the start, especially in newly established relationships — low-frequency but high-quality help is more likely to be appreciated than being constantly at someone’s beck and call. When friends ask for help, occasionally take the initiative, or say “This time’s not convenient, but I’ll do my best next time,” which can help rekindle their anticipation.

Second, create small variations to increase unpredictability. The brain loves surprises. Instead of mechanically repeating the same good deeds, change things up regularly, using different approaches. Even just altering how you show concern can have a surprisingly noticeable effect. Most importantly, gracefully maintain boundaries and learn to say no when needed. Every act of kindness should make the other person realize it’s not easy to come by, and setting boundaries is actually about maintaining a “psychological threshold” in emotional interactions. Occasionally saying no keeps the interaction fresh and respectful.

Ultimately, understanding the core of the Law of Habituation isn’t about calculating or manipulating others, but about learning to regulate your own sensitivity and make deliberate choices in giving. Don’t let your sense of value depend entirely on others’ reactions, and don’t treat kindness as a hard currency that’s always on sale. If you can apply this principle to self-awareness, every proactive act of kindness will carry more weight. Carefully manage your giving threshold — be sensitive when needed, be less sensitive when appropriate — and others’ responses won’t cause you to lose control of your social initiative.