Let’s go for a moment two million years back to an early form of hominids, who did not have language and abstract concepts yet. They acted on instinct. Just as the blow of a reflex hammer below the kneecap makes the leg twitch. Or the pupil shrinks as soon as a lamp illuminates it. Or piano players are pressing the correct keys at the required speed with the appropriate momentum to play a rehearsed piece of music without conscious control of the fingers. Our thinking started with inarticulate feelings. Over time, our mind evolved – our thinking, our speech, and our deliberate actions. Until now, we do not know how consciousness functions. However, as we interact with the world, we follow the Cycle of consciousness. Those who are still reading hither are already using their thinking skills. The mental models, ideas, themes, and concepts have been crucial in determining how curious readers still are.

Let us consider in the following how thinking might have developed since the beginning. However, the actual development remains hidden from us.

• Thinking 1.0 – Speech
  Scientists assume that humans imitated sounds of the environment onomatopoeically in the beginning. We still use the so-called onomatopoeia nowadays to depict the audible world – quack, tick-tock, splash. Over time, this expression mode has expanded to include inaudible and abstract things – looking, believing, calculating. Neanderthals could speak three hundred thousand years ago and Homo sapiens for at least sixty thousand years. Since those beginnings, an estimated 7000 languages have survived until today. Eighty percent are distributed among 50 mother tongues. Knowledge from these early times could only be passed on orally. Today we can only guess what thoughts and words, contents, and meanings were exchanged orally in the past. It means that the mental models of past generations remain inaccessible to us. However, the heritage of onomatopoeic expression is still in us. We continue to internalize sonically charged messages better – She clicks through the web page. The car rumbles through the street.
• Thinking 2.0 – Writing
  The earliest “written” evidence of humans is over thirty thousand years old. It survived in the darkness of inaccessible caves. Among the known rock drawings of animals and humans, Genevieve von Petzinger found characters, some of which are still found in computer characters today (×, Ο, ↑, ∇, #, ∼, ♥, ω, -). The writing was invented over eight thousand years ago. In the beginning, administrators kept stock records. The oldest evidence of writing is the Jiahu symbols, from China, which is almost 9000 years old. The more durable the medium (i.e., stone, clay, metal plates, papyrus, leather, and linen), the more evidence can be found. For the most part, we understand the evidence we find. An exception is, for instance, the Voynich manuscript, whose writing, imagery, and meaning have yet to be decoded. Although we can decipher the scripture, we often lack the pronunciation and original meaning of the phrases. Until the advent of mechanical reproduction, especially letterpress printing with movable type, scribes produced written documents manually. Handwritten manuscripts still convey a sense of credibility. However, as with speech, there is much room for different interpretations in texts. By putting our thoughts on paper, readers have more time to engage with the content than with quickly evaporating talk.
• Thinking 3.0 – Media
  The reproduction of written documents took place at an early stage on papyri, scrolls, wooden tablets, parchments, or papers. Since the eighth century, printers have used wooden types. In the sixth century, over 13 thousand books were produced manually in Western Europe. With Gutenberg, the information age began in the middle of the 15th century. Individuals could reach many readers (1 to n). From then on, the mental models of readers were confronted with familiar thoughts from the neighborhood and contemporary views from all over the world. By 1800, circulations in Western Europe approached one billion print copies. In Germany alone, nearly 400 million books were printed in 2013. The global reach of books means that the most exotic ideas can now get to remote places. Knowledge is thus expanding, becoming more diverse, more contradictory, but also harder to overview. To handle the flood of information, we try to protect ourselves from too many points of view. We defame those that differ from our own opinion as fake news without noticing that our statements might already be fake. With the rise of the Internet, complexity increases further.
• Thinking 4.0 – Internet
  In the nineties of the last century, the World Wide Web reached the public. Since then, anyone with access to the Internet has been able to contact every single person in the world. Interconnectedness thus creates an alternative, earth-spanning room for all previous forms of expression – monologue, dialogue, and discussion. The monologue talk (1 to n) that takes place these days on, for example, Facebook, YouTube, or Spotify now reaches not only bystanders but everyone connected worldwide. The two-way conversation (1 to 1) is also extended across geographical boundaries through videotelephony. Chats and video telephony allow us to take up contact with others and share our thoughts. Discussions (n to m) virtually occur in video conferencing, such as Zoom, Teams, and Skype. Here, many people can participate in an event. Just as geographical boundaries become less disturbing, the requirements for participants increase. They need new skills, such as computer literacy, multilingualism, cultural understanding, and empathetic behavior. Did you ever enter Chinese or Japanese forums? Despite the constantly improving machine translators, these cultural abysses are difficult to cross.
• Thinking 5.0 – Artificial Intelligence (AI)
  Researchers have been trying to create Artificial Intelligence for decades. After the AI winter at the end of the last century, due to disappointed expectations, increased computer power and new ways of “configuration” are creating an AI spring. In 1997, DeepBlue put Gerry Kasparov in checkmate. In 2015, DeepMind defeated Fan Hui, the European Go champion. Since 2006, Google Translate has been transmitted automatically from one language to over a hundred others. The intriguing question is whether thinking is required for this. John Searle distinguishes between weak AI, which simulates the mind, and strong AI, which has a mind (John Searle, Mind, 2004). In everyday life, it will become increasingly harder to distinguish machines from people. Quantum computers process data in parallel at unprecedented speeds. Machine learning is replacing programming algorithms and delivering impressive results for most of us. Current examples are autonomous vehicles, which are already reaching the level of human error. However, it is a matter of faith whether the machine is capable of thinking. In the end, this even cannot be proven for humans. In any case, this already allows today results that humans can only achieve with great effort, if at all.

Bottom line: Based on the above developmental stages, it may have become apparent that thinking went through different stages: speech, writing, media, Internet, and AI. Our environment has a significant influence on how thinking evolves. It appears in diverse cultures and their mental models. The stories of feral children show the impact of the environment on behavior and speech. Subliminally, the different stages still affect everyday interaction. For example, if we hear Bouba, we have a rounded shape predominantly in mind  and with Kiki a more of a jagged one  . With writing, we convey content without personal contact. The natural flood of information became possible through media and its mass products. With the Internet, we have arrived in the global village, where again individuals exchange ideas – worldwide. Artificial intelligence casts its first shadows when we stop memorizing but immediately google when we have questions. Despite all progress, the levels are still at work in our minds. Attention! Those who master the mechanisms control the rest of us.