2026年机经41

Earlier in class, we talked about the Dutch Tulip Craze of the early 1600s, a time when tulip bulbs became luxury symbols, prices soared, and fortunes vanished almost overnight. It was one of history's first economic bubbles, fueled by speculation and status. America had its own version in the early 19th century when the country was swept up in the mulberry craze. The idea sounded simple: plant mulberry trees, raise the silkworms that eat their leaves, collect the silk from the worms' cocoons, and rake in the profits. Silk was a prized luxury import, and producing it locally promised enormous wealth. Farmers and investors rushed to buy mulberry saplings. Prices for the young trees soared from pennies to several dollars—classic bubble behavior. And the speculation wasn't all about money. Silk itself, the idea of silk, carried powerful symbolism: refinement, status, and aspiration. For a brief moment, middle-class Americans imagined silk dresses as attainable, blurring old class distinctions. But reality intervened. Silkworms are delicate, requiring precise care and stable climates. Harsh winters wiped out silkworm populations across the country. Mulberry groves lost their purpose, The trees lost their value. The bubble burst, and by the mid-1840s, folks who'd invested their fortunes in the venture were ruined financially. And the bottom line? I mean, for us today? Well, just like Tulip Mania in the Netherlands, the American Mulberry Craze shows how ambition and hype can outpace ecological and practical limits. This is a cautionary tale for modern-day investment booms.

In recent years, more people have started growing plants in urban spaces, a practice known as urban gardening. This includes cultivating plants on rooftops, balconies, and in community gardens. Urban gardening can help reduce some negative effects of urbanization, such as pollution. One benefit is improved air quality. Plants absorb carbon dioxide and release oxygen. Which helps clean the air and make cities more livable. Another advantage is enhanced food security. By growing their own produce, city residents can access fresh, healthy food and rely less on commercial agriculture. This is especially helpful in deserts, areas where access to fruits and vegetables is limited. Imagine an abandoned plot in a city, maybe a piece of land where an old factory used to be. Now imagine clearing the land and building a small community center surrounded by garden plots. People from the neighborhood come to workshops to learn how to plant and cultivate spinach, strawberries, tomatoes—whatever produce they want. These neighborhood volunteers then cultivate the garden plots and harvest their produce. As you can imagine, this would bring people together and encourage cooperation and shared responsibility. However, there are challenges to urban gardening, such as soil contamination. In some instances, the soil may contain harmful substances like heavy metals or industrial chemicals. Gardeners often need to test and treat the soil or use raised beds with clean soil to ensure safe growing conditions. Despite these obstacles, cities are adopting policies to support gardening and improve residents' quality of life.

Imagine you're a painter. Now, would your passion for painting be driven purely by internal motivation? In other words, would you paint just for the joy of it? What if you're being paid for your paintings? Intuitively, we might assume that an external reward, or financial incentive would amplify your motivation. But that's not the case. Paradoxically, the opposite often occurs, a phenomenon known in psychology as the overjustification effect. Intrinsic motivation decreases when external incentives come into play. Let me describe an experiment from the 1970s. Children who naturally gravitated toward drawing with markers were observed. Some children were promised rewards for their drawings. Then, during free time, the group that expected rewards spent significantly less time drawing compared to other kids, suggesting that extrinsic rewards can lower an individual's interest. The underlying mechanism here is a perceived shift in autonomy. So, take an activity that's initially pursued just for the fun of it. Introduce an external reward, and individuals feel their actions are no longer self-driven, but driven by the reward itself. The activity feels more like an obligation than a passion. And you can imagine implications across various fields. Education, business, where encouraging intrinsic motivation is crucial. Students or employees who are rewarded for activities they already enjoy could lose their natural enthusiasm over time. Understanding the overjustification effect can help us when we're creating settings intended to nurture, not suppress, intrinsic motivation.

During the Roman Empire, soldiers had a lot of, uh, weapons and armor, and they needed a place to store them. Their arms and armor soldiers used boxes called armariums to store this gear. Armariums were big portable wooden storage boxes. Later, people, including civilians, kept using armariums in their homes, but to store items like clothing, books, or other valuables. In France in the 16th century, wealthy people had them and called them armoires. Armoire is a term we still use today for a large, standalone piece of wooden furniture for storing things. Around the same time, some homes in England started to have what they called closets. But these closets were more like, uh, small studies where people could store things or also just read or be alone. Someone might play their guitar in one to relax. So both the armoire and the English closet, they were kinda precursors to the modern closet. If we fast forward to the mid-1800s in the early United States, We're starting to see closets that are built directly into homes as part of the floor plan. The big benefit of these was that they were less pricey than armoires—way cheaper! People had less clothing then than they do today, and they'd usually use a small chest to store clothes, or hang them on a peg or hook. Coat hangers weren't invented until the late 1800s. But still, closets in the home were handy places to store other belongings.