After a person has experienced a strong stimulus, any subsequent stimulus becomes insignificant to that person. In short, a major first stimulus can diminish the impact of a smaller second stimulus. When introducing this law, many people use romantic relationships as the subject and describe it from the victim’s perspective, which makes it easier for people to empathize. However, many people do not realize that stimuli—whether positive events or negative ones—are all subject to the Weber–Fechner Law.
Based on the characteristics of this law, we can identify two very interesting human phenomena: asking for an inch after being given a foot, and becoming numb and indifferent.
Getting an inch and wanting a mile: in other words, the positive effects of continuous and stable rewards diminish over time, causing people to underestimate sustained benefits. For example, when most people are transferred to a new position with a salary increase, they are initially very happy, but after a few months they become accustomed to it and instead start complaining that their commissions have decreased. They then become increasingly dissatisfied with their work and may even plan to seek opportunities elsewhere. But if you think rationally, a consistently high salary is almost certainly better than unstable commissions. There are also people who become especially moved, even bursting into tears, when they occasionally receive help from strangers, yet turn a blind eye to the care and attention of the person beside them. Without even doing the math, the benefits gained from the continued care of someone close to us are far greater than those from a single act of help by a stranger. This is what it means to get an inch and want a mile.
Numb and callous: here, “callous” means having no sensation. In other words, the same kind of continuous negative stimulation also gradually returns to normal over time. Of course, this cognitive bias is also a form of self-protection. For example, when people have been troubled by a certain illness for many years, they gradually adapt to the state of being ill as time passes. When most people face some kind of misfortune, if they know that it cannot be changed, they will also develop an attitude of calmly facing it after it continues for a period of time. This is what it means to become numb and callous.
It is worth noting that this continuous negative stimulation must be stable: there should be no variation in the type of stimulation or in the severity of the harm. In other words, misfortunes may come one after another, but please do not let them fluctuate in intensity; otherwise, because we cannot anticipate the harm, we will never have peace.
The reason these two interesting things happen is that we humans have two basic instincts: seeking benefits and avoiding harm. We gradually undervalue ongoing benefits—that is, we keep wanting more and pushing our luck. That’s the instinct to seek benefits. We calmly accept ongoing pain in order to reduce suffering. Becoming numb and indifferent is the instinct to avoid harm. But this doesn’t mean we’re insatiable or deceiving ourselves; it’s simply our instincts following life’s basic algorithm, which is hard to change. Since it’s hard to change, we can make use of this principle. How?
First, when something has a diminishing effect over time, we can turn it into intermittent, random stimulation. Since people keep wanting more, be a little shameless: once you realize that surprising clients every time means it’s no longer a surprise, and that over time they’ll want more, you should vary the pace of your service so the surprises are unpredictable. Don’t just work relentlessly, all the time, until you’ve drained your creativity—only to find that the client is still dissatisfied.
Second, when faced with a small request, people tend to look back at the larger one that came before it. Rather than laying the groundwork with a big request followed by a small one, since they’ll become numb to it, you can be ruthless. When you want someone to be more willing to accept a request, you can first make a somewhat unreasonable demand. After they refuse, make the smaller request you actually want, and they’ll be more likely to accept it. You could say the room is too dark and suggest putting in a skylight, but everyone would surely object. If you instead advocate tearing off the roof, they’ll try to reach a compromise and agree to put in a skylight. Many instinctive patterns of thought and psychological effects can be exploited once they’ve been described. It’s good to think about how to use them to your advantage—or keep your eyes open to avoid being harmed by them.