Many people take the commonsense view that color is an objective property of things, or of the light that bounces off them. They say a tree's leaves are green because they reflect green light — a greenness that is just as real as the leaves. Others argue that color doesn't inhabit the physical world at all but exists only in the eye or mind of the viewer. They maintain that if a tree fell in a forest and no one was there to see it, its leaves would be colorless — and so would everything else. They say there is no such thing as color; there are only the people who see it. Both positions are, in a way, correct. Color is objective and subjective — "the place," as Paul Cézanne put it, "where our brain and the universe meet." Color is created when light from the world is registered by the eyes and interpreted by the brain.

Kids tire of their toys, college students get sick of cafeteria food, and sooner or later most of us lose interest in our favorite TV shows. The bottom line is that we humans are easily bored. But why should this be true? The answer lies buried deep in our nerve cells, which are designed to reduce their initial excited response to stimuli each time they occur. At the same time, these neurons enhance their responses to things that change — especially things that change quickly. We probably evolved this way because our ancestors got more survival value, for example, from attending to what was moving in a tree (such as a puma) than to the tree itself. Boredom in reaction to an unchanging environment turns down the level of neural excitation so that new stimuli (like our ancestor's hypothetical puma threat) stand out more. It's the neural equivalent of turning off a front door light to see the fireflies.

Some countries have proposed tougher guidelines for determining brain death when transplantation — transferring organs to others — is under consideration. In several European countries, there are legal requirements which specify that a whole team of doctors must agree over the diagnosis of death in the case of a potential donor. The reason for these strict regulations for diagnosing brain death in potential organ donors is, no doubt, to ease public fears of a premature diagnosis of brain death for the purpose of obtaining organs. But it is questionable whether these requirements reduce public suspicions as much as they create them. They certainly maintain mistaken beliefs that diagnosing brain death is an unreliable process lacking precision. As a matter of consistency, at least, criteria for diagnosing the deaths of organ donors should be exactly the same as for those for whom immediate burial or cremation is intended.

The term minimalism gives a negative impression to some people who think that it is all about sacrificing valuable possessions. This insecurity naturally stems from their attachment to their possessions. It is difficult to distance oneself from something that has been around for quite some time. Being an emotional animal, human beings give meaning to the things around them. So, the question arising here is that if minimalism will hurt one's emotions, why become a minimalist? The answer is very simple; the assumption of the question is fundamentally wrong. Minimalism does not hurt emotions. You might feel a bit sad while getting rid of a useless item but sooner than later, this feeling will be overcome by the joy of clarity. Minimalists never argue that you should leave every convenience of the modern era. They are of the view that you only need to eliminate stuff that is unused or not going to be used in the near future.

A remarkable characteristic of the visual system is that it has the ability of adapting itself. Psychologist George M Stratton made this clear in an impressive self-experiment. Stratton wore reversing glasses for several days, which literally turned the world upside down for him. In the beginning, this caused him great difficulties: just putting food in his mouth with a fork was a challenge for him. With time, however, his visual system adjusted to the new stimuli from reality, and he was able to act normally in his environment again, even seeing it upright when he concentrated. As he took off his reversing glasses, he was again confronted with problems: he used the wrong hand when he wanted to reach for something, for example. Fortunately, Stratton could reverse the perception, and he did not have to wear reversing glasses for the rest of his life. For him, everything returned to normal after one day.

Participants in a study were asked to answer questions like "Why does the moon have phases?" Half the participants were told to search for the answers on the internet, while the other half weren't allowed to do so. Then, in the second part of the study, all of the participants were presented with a new set of questions, such as "Why does Swiss cheese have holes?" These questions were unrelated to the ones asked during the first part of the study, so participants who used the internet had absolutely no advantage over those who hadn't. You would think that both sets of participants would be equally sure or unsure about how well they could answer the new questions. But those who used the internet in the first part of the study rated themselves as more knowledgeable than those who hadn't, even about questions they hadn't searched online for. The study suggests that having access to unrelated information was enough to pump up their intellectual confidence.

Anthropologist Gregory Bateson suggests that we tend to understand the world by focusing in on particular features within it. Take platypuses. We might zoom in so closely to their fur that each hair appears different. We might also zoom out to the extent where it appears as a single, uniform object. We might take the platypus as an individual, or we might treat it as part of a larger unit such as a species or an ecosystem. It's possible to move between many of these perspectives, although we may need some additional tools and skills to zoom in on individual pieces of hair or zoom out to entire ecosystems. Crucially, however, we can only take up one perspective at a time. We can pay attention to the varied behavior of individual animals, look at what unites them into a single species, or look at them as part of bigger ecological patterns. Every possible perspective involves emphasizing certain aspects and ignoring others.

Plato's realism includes all aspects of experience but is most easily explained by considering the nature of mathematical and geometrical objects such as circles. He asked the question, what is a circle? You might indicate a particular example carved into stone or drawn in the sand. However, Plato would point out that, if you looked closely enough, you would see that neither it, nor indeed any physical circle, was perfect. They all possessed flaws, and all were subject to change and decayed with time. So how can we talk about perfect circles if we cannot actually see or touch them? Plato's extraordinary answer was that the world we see is a poor reflection of a deeper unseen reality of Forms, or universals, where perfect cats chase perfect mice in perfect circles around perfect rocks. Plato believed that the Forms or universals are the true reality that exists in an invisible but perfect world beyond our senses.

The adolescent brain is not fully developed until its early twenties. This means the way the adolescents' decision-making circuits integrate and process information may put them at a disadvantage. One of their brain regions that matures later is the prefrontal cortex, which is the control center, tasked with thinking ahead and evaluating consequences. It is the area of the brain responsible for preventing you from sending off an initial angry text and modifying it with kinder words. On the other hand, the limbic system matures earlier, playing a central role in processing emotional responses. Because of its earlier development, it is more likely to influence decision-making. Decision-making in the adolescent brain is led by emotional factors more than the perception of consequences. Due to these differences, there is an imbalance between feeling-based decision-making ruled by the more mature limbic system and logical-based decision-making by the not-yet-mature prefrontal cortex. This may explain why some teens are more likely to make bad decisions.

The decline in the diversity of our food is an entirely human-made process. The biggest loss of crop diversity came in the decades that followed the Second World War. In an attempt to save millions from extreme hunger, crop scientists found ways to produce grains such as rice and wheat on an enormous scale. And thousands of traditional varieties were replaced by a small number of new super-productive ones. The strategy worked spectacularly well, at least to begin with. Because of it, grain production tripled, and between 1970 and 2020 the human population more than doubled. Leaving the contribution of that strategy to one side, the danger of creating more uniform crops is that they are more at risk when it comes to disasters. Specifically, a global food system that depends on just a narrow selection of plants has a greater chance of not being able to survive diseases, pests and climate extremes.

Many of the first models of cultural evolution drew noticeable connections between culture and genes by using concepts from theoretical population genetics and applying them to culture. Cultural patterns of transmission, innovation, and selection are conceptually likened to genetic processes of transmission, mutation, and selection. However, these approaches had to be modified to account for the differences between genetic and cultural transmission. For example, we do not expect the cultural transmission to follow the rules of genetic transmission strictly. If two biological parents have different forms of a cultural trait, their child is not necessarily equally likely to acquire the mother's or father's form of that trait. Further, a child can acquire cultural traits not only from its parents but also from nonparental adults and peers; thus, the frequency of a cultural trait in the population is relevant beyond just the probability that an individual's parents had that trait.