I'm so excited to tell you all about this amazing book! It was first published in English in 2023. Its English title is Sensational.

But, you know, because we're so used to relying on our senses, it can be tough to step back and see what they really mean for us. It's amazing how the senses not only give us a way to take in the world around us, but they're also a big part of who we are as people and shape our society and culture.

The saying that there are as many Hamlets as there are eyeballs is not only a literary and aesthetic assertion, but also an image-based summary of the characteristics of sensory operation. Isn't that fascinating? The author has a really interesting way of looking at the senses. They say that the reality we perceive is nothing more than a complex and beautiful set of illusions. Even though we've always thought that seeing is believing, it's important to remember that what we see can be influenced by a number of factors. These include our physical state, the way our brains work, our emotions, and other things. It's so interesting how every creature and every person perceives the world in their own unique way! We all see the world in different ways, and that's totally normal! We all have different materials for understanding the world, and that affects how we understand it and perceive ourselves. So, from this perspective, it's your senses that shape you, and that's a wonderful thing!

And let's not forget that our wonderful senses also help us to create culture and form society. As cultures and societies grow and change, they can also affect our senses in wonderful ways. Isn't it fascinating how different cultures have different preferences? Some cultures value sight, while others value smell more. Some societies use touch as a way to connect with each other, while others prefer to keep their distance. I think it's so lovely how the interaction between our senses, culture, and society has made our world so rich and colorful!

This book is all about the amazing senses we have! It gives a super detailed introduction to how our senses of sight, hearing, smell, taste and touch work, how they affect us and how they shape our cultural and social lives. We're all used to looking at the world from the outside in, through the doors of the world. But this time, we can look back at ourselves through these doors, with the author's guidance.

I'm delighted to introduce Ashley Ward, the wonderful British biologist and professor of animal behavior at the School of Life and Environment at the University of Sydney, who wrote this book. His main research interest is the sensory behavior of animals, and this book is a wonderful reflection of his lifelong passion. I think it's worth mentioning that Ashley Ward has poor eyesight and has lost his sense of smell and taste. I'm sure this experience helped him understand the importance of the senses in a deeper way.

All right, let's dive right in! I'm so excited to introduce you to this book! I'll be sharing it with you in three parts. First, we're going to chat about how our amazing senses have shaped us as humans. Then, we'll take a closer look at how our senses shape us as individuals. And finally, we'll explore how our senses shape our social lives.

1. The senses make us human, and they're pretty amazing! Let's start with how the senses make us human.

The ancient Greek philosopher Aristotle once made a very interesting observation. He pointed out that humans have five senses: sight, hearing, taste, smell, and touch. Today, his theory of the five senses is not considered accurate. As we will see later, humans have many other senses, but the five senses are indeed the most important ones. They have largely shaped today's humans, and we're going to dive into that now!

Let's start with vision, as it is often considered the primary sense. The retina is a thin layer at the back of the human eye. It's the key structure that provides vision, converting incident light into nerve signals. Isn't that amazing? The retina is a tiny little thing, about the size of a quarter bank card, but it has more than 100 million photoreceptor cells inside it! The two most important types are the "rod cells" and "cone cells." Rod cells are like our trusty little light detectors. They help us to see things in black and white and to perceive brightness. Cone cells are like our color detectors. They help us to see things in color. Our amazing eyes have three types of cone cells, each responsible for short, medium, and long wavelengths of light. These roughly correspond to blue, green, and red light, which is pretty cool! And they also respond to colors next to each other on the color spectrum. Isn't it amazing that our three types of cone cells work together to give us the ability to distinguish subtle differences in color?

It's pretty amazing when you think about it. From the perspective of color vision alone, humans are actually an anomaly among mammals. It's so interesting to learn that the vast majority of mammals are dichromats! This means that they only have two types of cone cells in their eyes. For example, our furry friends, dogs and cats, cannot see red or bright green when they look at the world. They have a limited color spectrum, which is made up of just two primary colors: yellow and blue. It's pretty amazing to think that apart from us humans, the only other mammals with three types of cone cells are our ape and monkey friends. They make up a very small proportion of the mammal world, but they're still pretty special! Birds and fish are quite different. They have a much richer sense of color! Fish are pretty amazing, too! They have a sense of color that's pretty similar to ours. But birds are in a league of their own! They have four types of cone cells and can see ultraviolet light, which we humans can't.

Humans are pretty amazing, aren't they? We're actually the best mammals when it comes to visual acuity! Have you ever wondered what visual acuity is? It's the amazing ability of our eyes to distinguish the fine structure of an object. The more details you can see, the better your visual acuity is! Birds of prey are the best example of visual acuity! They have extremely sharp eyesight and can easily see small animals on the ground while soaring through the sky. Even though we humans aren't quite as good at visual acuity as birds of prey, we're still pretty darn good at it compared to other mammals! Cats, for instance, have much less impressive visual acuity than we do. They can't see objects within 30 cm or objects 6 m away. Dogs are a little better, but they're still not quite as good as us.

We wish we could compare all aspects of vision, but we just don't have the space! From the performance of color vision and visual acuity, though, you can see that although human vision is not as good as those of the best students in nature, it is also outstanding among mammals. This just goes to show what we've always known: humans are a visual animal, and our amazing vision has helped us perceive the world in a big way.

Apart from sight, hearing is super important, especially when combined with language. It's thanks to this that humans have been able to develop a unique form of communication. Our amazing human bodies can hear sounds thanks to the cochlea, a snail-shell-like structure in our ears. The amazing cochlea is lined with hair cells, which are arranged in a sequence according to position. These cells can respond to sounds of different frequencies, recognizing sounds from 20 to 20,000 Hz! I'd love to know what you think this means! This means that we can hear a much wider range of frequencies than most animals, which is pretty cool!

And there's more! Our amazing ears are especially tuned in to sounds in the 1,000 to 6,000 Hz range, which is right where our voices live. Isn't it truly remarkable that we humans can speak? It's so interesting to think about how many animals make sounds, but only humans can truly communicate in a meaningful way. It's really hard to know where the ability to speak came from. Some studies even suggest that language ability might have popped up as recently as 150,000 to 50,000 years ago! Since then, our amazing ears have gradually adapted to language, developing maximum sensitivity to specific sound ranges for language frequencies.

Thanks to our amazing hearing and language abilities, we can communicate with each other quickly and efficiently. This allows us to connect and form societies, and it even helps us to create cultures where ideas can come together! It's safe to say that everything humans have achieved today is thanks to our amazing hearing abilities!

Next, let's take a peek at the sense of smell, which is often overlooked. Our ears are pretty amazing, aren't they? They have about 3,500 hair cells that sense sound, which seems like a lot, but it's nothing compared to the tens of millions of olfactory receptors in our noses! Our amazing human genome contains about 400 olfactory genes, each one encoding a different type of olfactory receptor. It's pretty amazing when you think about it! Genes come from both parents, so a person can have up to about 800 types of olfactory receptors. That's enough to perceive a wide range of different odors!

We often think of human olfaction as not being very sensitive, and it's true that we don't have as many receptors as dogs do. But here's the thing: human olfaction is actually pretty amazing in some ways, too! Isn't it amazing that we can smell certain substances at a concentration of less than 100 billionth, which is equivalent to less than one drop of water in an Olympic-sized swimming pool? In one study, researchers compared the olfactory sensitivity of humans and dogs to 15 chemical substances and found that we humans won in five of them! They're especially attuned to the sweet scents of flowers and fruits, while our furry friends are more tuned in to the aroma of their next meal. This study is really important because it shows us that our sense of smell is actually pretty impressive! Even though our noses aren't the most sensitive, we can still beat the canine "champion" in some areas!

Even though we humans are only just behind dogs when it comes to smell, we can make up for it when it comes to taste! Our amazing bodies are designed to perceive taste through tiny little structures called taste buds, which are mostly distributed on our trusty tongues. Humans are pretty lucky in the taste department, with between 5,000 and 10,000 taste buds, which is just about perfect! Carnivores have fewer taste buds than us humans. Dogs have only a quarter of the number of taste buds that we have, and even domestic cats have less than 500! On the other hand, herbivores have a lot more taste buds than we do! For example, cows have about 25,000. Herbivores have more taste buds than other animals because they need to be able to tell the difference between poisonous plants and the tasty greens they eat! Carnivores don't have to worry about this as much because their diet is pretty simple and their prey rarely contains toxins. So, they don't need to evolve a very sensitive sense of taste.

Humans are pretty much right in the middle, with a number of taste buds that are similar to those of omnivores. Absolutely! Humans are omnivores, through and through. Maybe it's these just-right number of taste buds that let us enjoy the deliciousness of veggies, fruits, and meat dishes! This is why taste has shaped the eating habits of humans.

Overall, humans are a pretty lucky bunch! We're so lucky to have such acute vision, sensitive and practical hearing, and a good enough sense of smell and taste! We're pretty much all-rounders! We don't have any obvious specialties, but we also don't have any shortfalls that hold us back. We can absolutely achieve excellent standards in each subject! It's thanks to these amazing senses that we humans have been able to stand out in the evolutionary race and achieve who we are today, as well as our society and culture.

2. Our senses help us to define who we are as individuals. Now that we've talked about how the senses have shaped the human species, let's focus our attention a little closer to home. As we all know, a person's physical condition is closely related to their gender, age, genes, and other factors. All these factors come together to create something really special: the unique sensory conditions that define each individual. Let's take a peek at what factors on a physiological level influence individual differences in human senses and how the senses define individuals.

One of the main things that makes us all different when it comes to our senses is our gender. As a general rule, women tend to have more sensitive senses than men. Take smell, for instance. It's not just that women can detect odors at lower concentrations. They also have a more expansive and nuanced olfactory experience. The good news is that this difference has a very simple explanation! It all comes down to the fact that the part of the brain that processes smell has 50% more neurons in women than in men. This is probably because the more sensitive sense of smell allows women to avoid toxic substances better during pregnancy.

And it's not just smell! Women's taste buds are also more sensitive than men's. Guess what! The number of taste buds doesn't change depending on whether you're a man or a woman. But here's something else that's different: women's taste receptors are more responsive. And it all comes down to the wonderful business of having and raising little ones! It's amazing how estrogen enhances women's perception of taste! So, it's no surprise that women of reproductive age have the sharpest sense of taste! And their sensitivity peaks during pregnancy. It's totally normal for women to be extra sensitive to bitterness during this time. It's actually a natural, protective mechanism that's been developed over time to keep our little ones safe!

As a general rule, women tend to have a slight edge over men when it comes to most basic senses. The only exceptions are visual acuity and motion sensitivity, where men tend to have a slight advantage. The author thinks this is probably because in the past few million years of hunting and gathering, men were the main hunters. They had to be really good at spotting prey, which probably made their vision more important than it is for women.

It's so interesting how gender, which is something we're all born with, can affect our senses in different ways throughout our lives. On the other hand, as we get older, our senses change a bit more often.

As we chatted about earlier, our human hearing range is 20 to 20,000 Hz. But, this figure doesn't apply to everyone. As we get older, our hearing range will naturally change a little bit, just like the ebb and flow of the tide. Once we hit our 20s, we'll lose about 1 Hz of hearing every day. By the time we reach our 50s, we'll basically be unable to hear sounds above 10,000 Hz.

As we get older, our sense of smell also tends to change. It's sad to say that by the time we reach 80, around three-quarters of us will have lost our sense of smell. This is why some older folks have what we lovingly refer to as the "old person's smell." It's not because they've become careless about hygiene as they get older. It's because, sadly, they really can't smell anything. It's a real shame, but the main reason for this decline in the sense of smell is that the number of olfactory neurons and nasal mucus both decrease with age. Many geriatric diseases also have the unfortunate side effect of a decline in the sense of smell.

As for the sense of touch, it's probably safe to say that it also declines with age. Did you know that our skin is made up of nearly 250,000 tiny nerve fibers? In the early years of life, something pretty amazing happens. The number of nerve fibers in our bodies increases with age, reaching a peak in our teens and twenties. And then, as we all know too well, it's that familiar feeling of decline. It's so sad, but every ten years, people lose about 8% of their nerve fibers. By the time they reach 80, the total number is only half of what it was! It's really sad that the loss of nerve fibers is most noticeable in the hands, feet, and face. These are the parts of our body that are most sensitive to touch and have the most colorful tactile experiences.

We can't avoid aging, and as we get older, our hearing and vision naturally change. As we age, our senses can become a bit like windows and doors that are hard to keep clean. Over time, they can become a little blurred with the accumulation of dust. This is how our senses define aging. The best we can do is to understand and be more tolerant of aging.

It's not just gender and age that affect our senses. Our genes also play a big part. Let's take the sense of smell as an example. Everyone's nose is special and perceives odors in their own unique way. Take the sense of smell as an example. Everyone can smell a lemon, but we all experience it in our own unique way. I'd love to know why this is!

It all comes down to our genes. Isn't it fascinating? Each human olfactory receptor has a specific genetic code! It's truly fascinating to think that among humans worldwide, there are millions of variations in the 400 olfactory genes! In other words, it's pretty unlikely that two people will have the same set of olfactory receptors! Because everyone has their own special olfactory experience, this olfactory difference is also known as a person's "olfactory fingerprint."

Each of us is wonderfully unique, with our own special combination of gender, age, genes, and other factors that make up our individual senses. It's amazing how our senses shape our experiences of the world and our sense of self. This is why our senses make us who we are. They help us to become different people, and that's a wonderful thing!

3. Our senses and culture are so closely connected! It's so interesting how societies interact with each other!

If the portal to the world of the senses is the most intuitive influence on us at the physical level, then its deeper transformation of human beings is inseparable from the role of society and culture. Next, we'll dive into how the senses connect with society and culture in a really interesting way.

It's so clear that our senses are the foundation of our social and cultural development. Our senses are the gateway to the world for each and every one of us. They provide us with all the material we need to understand the world around us. It's pretty obvious that what we see and hear is really important for our survival. I'd love to use the example of touch to show you how important the senses are for social and cultural development.

Did you know that chimpanzees and bonobos are the two ape species in the natural world that are most closely related to us humans? In their society, every member spends five hours a day showing love and affection by carefully stroking each other, grooming and tickling each other. This is great for keeping our bodies clean, but it's even better for keeping our social bonds strong! The lovely act of mutual stroking releases oxytocin, which makes us feel more connected to each other. This is why touch is such an important part of ape societies. It helps to keep everyone connected!

And it's the same for human societies too! In our daily lives, we might not think about how important our senses are to each other, but some extreme examples can show us the consequences of a lack of senses. In the 13th century, the Holy Roman Emperor Frederick II had a fascinating idea. He wanted to find out what language the mythical Adam and Eve spoke. So, he ordered a group of babies to be taken from their mothers and raised in complete silence. Once they started talking, they would only speak their native language, which was surely that of Adam and Eve.

At Frederick II's request, the nannies caring for the babies were asked to refrain from speaking to them or having any unnecessary physical contact with them. Even though the babies were fed and bathed, they were completely without human contact because there was no intimate physical contact or conversation. Sadly, these poor children fell ill and died one by one. They never got the chance to grow up and speak. It's pretty clear that being able to communicate through our senses is essential for our survival. It's also a big part of how we build and maintain our societies and cultures.

It's so important to understand how our senses shape our lives and our communities. And it's fascinating to see how our communities influence our senses!

First, culture can affect how we experience the world through our senses. A great example of this is a classic comparative study based on language and color. English has 11 lovely color terms, while Korean has 15! Isn't it fascinating how different languages represent colors in different ways? For instance, in Korean, there are two words for "green," one for a yellow-green and the other for a true green. This shows that Korean makes finer distinctions between colors, which is pretty cool! And guess what? The experiment also found that native Korean speakers are better at distinguishing shades of green than native English speakers! This high correlation between language and vision shows us that culture can really influence how we experience the world through our senses.

Another study really goes to show this, too! We all love almonds, don't we? They're a common dessert ingredient in the United States, but in Japan they're often used as a savoury snack. The researchers decided to test this out in an experiment. The smell of benzaldehyde is very similar to that of almonds! The researchers kindly asked volunteers to smell benzaldehyde at a very low concentration—one that was difficult to detect directly—while at the same time tasting a drop of liquid. The liquid could be either pure water, salty water with added monosodium glutamate, or sweet water with added saccharin. Whatever it was, it was delicious!

The results were really quite fascinating! When the American volunteers tasted the sweet water, they immediately recognized the faint smell of benzaldehyde in the air. They were so clever! However, when they tasted the pure water or salty water, they didn't seem to react much. When the Japanese volunteers tried the same experiment, they found that salty water was the liquid that brought out the benzaldehyde smell. This experiment showed us something really interesting! It seems that our neurons in the human brain make specific associations between culture and the senses. If your culture often associates almonds with sweetness, then your brain will be really good at linking sweetness with almonds! If you think almonds are salty, you'll be more sensitive to the taste of salt. This is why the experiences we have through our senses aren't totally objective. They're actually influenced by culture and seen through a cultural lens.

Sometimes, culture can even influence how we perceive the importance of our senses! If someone were to ask you which sense is most important to you, I think most people would say sight. And you know what? That's actually true! It's pretty amazing to think that nearly three-quarters of English words are based on visual experiences! It's quite different when you think about smells, with less than 1% of words relating to that sense. English doesn't have a lot of words to describe smells, does it? It can be summed up in a few words, like "aromatic" or "musty," or it can be associated with something else, like smelling like mint or like citrus. This linguistic inability to express ourselves adequately makes the image of a smell in our mind even more hazy and ineffable. It's so sad that in modern times, people are kept away from nature because of their busy lives. This makes it harder for us to connect with smells and realize how important our sense of smell is.

But in other societies, the sense of smell is used in a totally different way! The lovely Desana people who live in the Amazon rainforest call themselves "wira," which means "people who smell." The lovely Desana people learn to track the scent trails in the air from a very young age. They can identify animals and plants by their scents, navigate in the forest, and even distinguish between different communities around them by their scents! The lovely Angke people living in the Andaman Islands also have a soft spot for the sense of smell and admire odors. Each season is defined by the lovely aroma of the flowers that bloom at that time of year. When they meet and greet each other, they also ask each other, "How's your nose?" This greeting might sound a little unusual, but it truly shows how important the sense of smell is to them.

It's not just about how important the senses are, but also about the social and cultural influences that shape our sensory preferences. Let's take touch as an example. In the 1960s, the wonderful Sydney J. Jurgens, a Canadian psychologist, studied how customers interacted in cafés in different parts of the world. He discovered something really interesting! It turns out that Londoners are the most reserved when it comes to physical contact. They don't touch each other at all! Americans were a little more enthusiastic, touching each other about two times an hour on average. In France and Puerto Rico, people just couldn't get enough of touching each other! They averaged 110 and 180 touches per hour, respectively. It's so interesting how people's preferences for touching each other can differ so much! It's a great example of how social culture can influence us.

It's amazing how social culture can influence everything, even what we eat! Diet and taste preferences are closely related, and they're both shaped by social culture. Moreover, it's not just about climbing the leadership ladder. It's about understanding the big picture and making changes that align with the market and the company's values. The first level of leadership is all about keeping things efficient, keeping costs down, and making a profit. It's a utilitarian approach that's all about taking. But, since the middle of the 20th century, something pretty amazing has happened. We've entered the era of the experience economy! I truly believe that the best profits come from spiritual experiences, not just goods.

The author makes a great point: you can measure how many tables a waiter has cleaned, but you can't measure his smile. And if you try, he'll fake it! On top of that, the global economy is becoming more and more uncertain. People are starting to question the idea of relying on yourself to get ahead at work. Against this background, it's no surprise that employees' expectations of organizations and society's standards of "what exactly is a good organization" have begun to change.

We want companies to be more than just a place to work. We want them to be a place where we can feel at home, and where we can let our emotions run free. It's not just a transactional relationship. It's also about forming an emotional connection, sharing values, and accepting the individual. The book says that there's a voice inside us all that says, "As long as I'm professional enough, I'll know how to do it and not care about how I feel." Only children are so sweet! They act based on their feelings. But there's another voice that says, "In a company with such a relationship of interests, is it too idealistic to talk about emotions and feelings?" But if you really think about it, does your feeling affect your performance? I'd love to hear your thoughts on this! I'm sure everyone will say yes!

So, maybe thinking that a complex person can become a one-dimensional machine after entering a market relationship is a bit simplistic, don't you think? Of course, don't worry! Practicing the third level of leadership doesn't mean completely abandoning the first level of leadership and efficiency-centeredness. I truly believe that functionality is the foundation of a business. It would be great if we could find a way to make emotion and efficiency work together to create the best possible situation for everyone! It's even possible for an organization to show that it can do more than just get the job done. In fact, it can create more economic value! I'd love to share an example that really impressed me with you. One year, I was delighted to volunteer to help organize a company visit. My colleague and I got there a little early to get things ready.

The lovely girl in charge of reception told us, "Oh, I'm so sorry! Let's change to another meeting room." "Oh, those windows in that room don't close properly." On the way there, we had a good laugh and said, "Our customers are like our pandas – they can't get sick!" I instantly felt a great impression of this company. I'm sure she didn't mean to!

It's one thing to make sure employees are trained to do the reception process meticulously, but it's another thing to control whether they'll considerately think about whether the customer will feel cold. The lovely thing about this process is that it's all about the emotional side of a company, beyond just efficiency.

Treat people as the wonderful individuals they are!

How can we best serve as leaders at the third level? This is a really big topic, and it's so important! The book is full of helpful tips and techniques!

For instance, a leader can help employees connect their actions with the company's values by exploring what motivates them. It's also super important for leaders to have a strong moral foundation, because that's what helps them inspire others. There are four main practices for effective leaders. They might sound simple, but they're not easy to achieve! And the four main things we can all do to be more effective leaders are: tell the truth, keep promises, be fair, and respect individuals. This is the only way you can gain the recognition of your employees on a values level.

At the heart of it all is a simple question: do you see each person as an individual, or as a role? If you see each person as an individual, they'll naturally do the right thing. For instance, you can often guess what someone's values are based on how they act.

This means being curious about the person as a human being, just as you are. They, just like you, have their own inner passions and are influenced by the ideas that surround them. It's so important to understand the values of others. That's the only way you can influence them, resonate with them, and inspire them to follow. Another great example is paying attention to how the other person is feeling.

We all know that employees are not cold machines. If you can see his emotions and help him deal with them, you'll win his heart! He'll recognize your kindness and even be grateful to you. Hey there! Why not ask a question? Do you think you could recognize the emotions of your colleagues? After all, you work with them every day! Would you be willing to help them manage their emotions? Another great example is that leaders should always keep their promises.