The Power of Time Perception

by Jean Paul Zogby

  Chapter 2

  How Do Our Brains Perceive Reality?

  All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.

  ― Emmanuel Kant

  The Real Purpose of Our Brain

  If you look closely at yourself in a mirror, behind those great looks lies the sophisticated world of the most complex organ ever to be produced in the history of this universe: the human brain. Weighing around 1.4 kg, the brain is made up of around 100 billion neuron cells and each neuron is connected to 10,000 other neurons, with the total connection exceeding the number of stars in the Milky Way Galaxy. That is how complex the brain is. But what is the purpose of such a complex organ?

  From an evolutionary point of view, one of the main reasons for our brain is not to help us think, feel, or create art, but actually to control the movement of our body. According to neuroscientists, a brain is useless in an organism that does not move. Consider plants and trees. They do not have a brain because they do not need to move. The sea squirt is a good example; it starts its life as a small tadpole that has one eye, one tail, and a very primitive brain that guides its movement in water. In the second part of its life, it searches for a suitable piece of rock to attach to for the remainder of its life and never moves again. Once it stops moving, does it use that time to contemplate on the meaning of life? No, it eats its own brain for energy!

  Our brains have evolved over millions of years, perfecting the way we move, long before we started developing any of the more sophisticated functions of thinking and planning. But why is movement so important? Remember that we evolved in a ruthless environment: eat or be eaten. Our ancestors had to develop the ability to move in search of food while avoiding becoming food themselves. That is the reason why our brains are counter-intuitively located inside our head. It would have made more sense for nature to place the brain in the chest area for better protection, rather than attaching it to the rest of the body by such a weak slim stem as our neck. But the brain is best located in the head because the eyes, ears, and nose are also situated there. These three sensory organs are best positioned in the head where they get the best view and optimal orientation when looking, sniffing, or listening for desired targets. With their millions of receptors receiving signals, such as light, smells, and sound vibrations from far distances, the sensory organs transmit critical information to the brain through a sophisticated network of neurons. The closer the brain is to those sensory organs, the faster the transmission speed. The eyes, ears and nose are essentially just an extension of the brain. They provide an early warning system for locating potential prey and predators, giving the brain enough time to react with a suitable plan of action. This power of prediction is the engine driving the evolution of intelligence in all animal species, especially humans. But what does this have to do with time?

  Time is nothing but the measure of change. Without change, time would not exist. The great physicist John Wheeler says, “Time is what keeps everything from happening at once.” Understanding how our brains perceive changing reality is vital to understanding time and how we experience it. As we shall see, the need to track motion and change is what produced our sense of time.

  We Do Not “See” What is Real

  One aspect of in our perception of reality is the fact that we only experience a partial image of reality, one that is filtered by our primary senses. Our senses of sight, hearing, smell, taste, and touch create signals that are used to paint a picture of reality, and this differs from what is actually out there. For instance, red light has a wavelength of around 650 nanometers, and this is constant regardless of the observer. But what you see as “red” is purely subjective and might be different from my perception of “red,” depending on how each of our brains process that color wavelength. There is no way to tell if your red is the same as mine, even though the same light wave is being reflected off that apple. In fact, color does not really exist in the real world in the same way that material objects exist, but it is instead a figment of our brain and is created from signals that are filtered by our unique senses. In the same way, we can all agree that chocolate tastes good, but there is no way for someone to know exactly how chocolate tastes to you. We do not see and taste what is real; only what we “think” is real. There is an important distinction between the world as it is and the world as we perceive it, and we can never truly have access to the former, as the philosopher Emmanuel Kant duly observed. If you have seen the movie The Matrix, you will recall a central question about what is real and how reality is defined. The reality that we feel, smell, taste, and see is a set of electrical signals created by our brains, even though they produce an image in our mind that is spectacular in its beauty and splendor.

  How Our Brains Lag Behind Reality

  In addition to the fact that due to our brain’s filtering mechanism we do not perceive true reality, we also lag in time behind reality. The senses gather information from the outside world and send it to designated areas in the brain for processing. The brain’s processing speed can be defined as the time it takes the brain to receive information, process it, and give an appropriate response. When you detect the scent of baking cookies, see the color of a flower, or hear the ringing of an alarm clock, it takes a fraction of a second for your brain to recognize that signal, identify a possible source, and respond. That fraction of a second is your reaction time. Psychologists use reaction time tests to study the speed of the brain’s processing capabilities. They found that it takes about one tenth of a second for signals to reach the brain, even when we are concentrating. This means that, for example, if you have to suddenly step on the car brakes because of an obstacle that appears in front of you, there will always be a time lag of at least one-tenth of a second between when the obstacle appears and when your brain processes the information and decides on a response.

  The notion that signals take time to travel to the brain came as a surprise in the 19th century, as it was in conflict with the popular idea that the world was experienced instantaneously, as it happened, i.e. without any lag between sensation and awareness. In 1850, German physiologist Hermann von Helmholtz experimented with frogs by connecting their leg muscles to wire so that when the muscle contracted it switched on a lamp in a circuit. By showing the frog scary images that caused its legs to contract, he found that it took about a tenth of a second (or 100 milliseconds) for a signal to travel from the brain to the muscle and cause the lamp to switch on. In another experiment, Helmholtz applied mild electric shocks to people’s skin and asked them to give a sign as soon as they felt it. In spite of the participants’ dismay, his results confirmed that sensory signals took time to travel to the brain. In fact, people took longer to respond to shocks that were applied to the toe because the path to the brain was longer, as compared to shocks applied to the lower back.

  Of our five senses, vision is responsible for the largest portion of information processed by the brain. Hearing complements vision even though each perceives the world in a different way. When you hear a car honk, you can find out which car made the sound by detecting the direction the sound came from and looking at the car closest to it. Our brain integrates both to perceive reality in a seamless way. The speeds at which these signals travel to the brain vary from one sense to another. All sensory signals arrive at different areas of the brain at slightly different times and are processed at different speeds. However, the color, motion, and sound signals of a red Ferrari that is zooming past you are all combined into a single perception in your mind, even though the processing of these sensory signals is distributed throughout several locations in the brain. The brain’s auditory cortex, for instance, processes an audio signal from your ear faster than a visual signal is processed in the visual cortex. The difference is around 40 milliseconds, which is not much, but it is enough to justify using a gun for starting a race, instead of a light flash. The faster audio processing speed means that sprint run
ners react more quickly to a bang than to a flash of light. This, incidentally, is another vestige of evolution that we inherited from our days in the jungle, when we could hear a tiger long before we could see it!

  The brain must account for the discrepancies in travel time and processing speeds yet still manage to synchronize all incoming signals and construct an extremely precise and unified perception of the world. An example of this synchronization was discovered when people started watching TV in the 1960s. In the early days of television broadcasting, engineers found it problematic to keep audio and video signals synchronized. They then accidentally discovered that as long as the signals arrived within one tenth of a second, or 100 milliseconds of each other, the viewers’ brains would automatically synchronize the signals and not notice the lag. If the time difference between receiving the audio and video signals was more than 100 milliseconds, the broadcast would appear like a poorly dubbed Chinese Kung Fu movie. The reason was revealed when neuroscientists found a 100-millisecond delay from the moment something is sensed to the moment it is registered in your brain. The brain needs that split second to integrate various information arriving from all senses and tag them together as a single event. To do that, the brain has to wait for the slowest sensory signal to catch up with the fastest, so that it sends them off all at once. What you are seeing right now on this page is actually a delayed live broadcast! Your eyes sensed it 100 milliseconds ago. It is as if you are constantly living in the past, like a radio station that broadcasts with a five-second delay to avoid bloopers. You might say 100 milliseconds are not much. Negligible, right? Well, apparently not.

  Using the brain’s ability to synchronize and integrate various sensory signals, scientists can play weird tricks with the brain. In 2006, American neuroscientist Dr. David Eagleman, along with his collaborators, came up with an experiment to investigate how synchronization affects our sense of causality. 13 Volunteers played a computer game in which a light flashed when they clicked the mouse button. Unknown to the participants, the experimenters then introduced a fixed delay of 150 milliseconds between the mouse click and the light flash. However, after a few tries, the participants playing the game quickly adapted to the delay and felt as though the flash appeared immediately after the mouse click. Their brains automatically adjusted for that delay, subconsciously cutting it out completely, in the same way that viewers of early TV broadcasts automatically synchronized the lag between audio and video signals. Now the fascinating discovery was that when the experimenters later removed the delay, the volunteers started seeing the flash before they even pressed the button! What had happened was that the brain was tricked and started switching the order of events so that they were seeing the outcome before the action. Cause and effect were reversed. It was as if time was going backwards!

  Neurotransmitters: The Brain’s Messengers

  The synchronization and processing of sensory signals occurs in a fraction of a second. The processing speed depends on how fast the brain neurons can talk to each other, which in turn depends on the level of brain chemicals called neurotransmitters. Our thoughts, emotions, and actions rely on these chemical messengers and their role in allowing neurons to communicate. When one neuron wants to transmit an electric signal to the next, it releases a neurotransmitter into the space between them. The neurotransmitter binds to a receptor on the other side, which then transmits the signal to the adjacent neuron. The adjacent neuron then repeats the same sequence, and so on so forth (several hundred times per second). Neurons fire, reset, and fire again at phenomenal speeds, such that if you were to stretch a series of neurons across a football field, an electric signal could traverse the full length in just one second.

  Neuroscientists have so far discovered over 50 neurotransmitters in the brain and identified which ones are responsible for processing information. They found that neurotransmitters, such as dopamine, play an important role in time perception. Time is a measure of change and the perceived speed of time is a measure of how fast we perceive change. This in turn depends on how fast the brain can process the ever changing sensations detected by our senses. The brains information processing speed relies heavily on the amount of neurotransmitters that are available in the brain for communication. Neuroscientists also found that abnormal levels of these brain chemicals are linked to most mental disorders like schizophrenia, Parkinson’s disease, ADHD, mania, or depression and, in some cases, they are the drivers of creativity and genius. Too much or too little of these brain neurotransmitters will affect the various brain functions like alertness, attention, and information processing speed. But what is relevant to our subject is the fact that the amount of these neurotransmitters play an important role in how fast we experience the subjective flow of time.

  The infinitesimal time it takes for our brain to process sensory information determines how fast we can absorb the ever-changing reality around us. As we shall see later, this brain processing speed, in turn, affects how fast we experience time. Therefore, it is important to understand the brain mechanisms that are behind this processing speed and how scientists measure it.

  Brainwaves: The Brain’s Electricity

  When groups of neurons release brain neurotransmitters to communicate and process sensory information, they generate spikes of electrical activity inside the brain. This was first observed in 1875 by British electro-physiologist Richard Caton when he introduced an electrode in a monkey’s brain, laying the groundwork for the discovery of brainwaves. Following that discovery, in 1924, German Psychiatrist Hans Berger invented the EEG (Electroencephalography) to record brain electrical activity and brainwaves. The story goes that Hans was in military service when he fell from his horse and landed in the path of a horse-drawn cannon. Luckily, the driver halted the horses in time, leaving Hans shaken but with no serious injuries. At the same time, his sister who was at home many miles away had a feeling he was in danger and sent him a telegram. That incident made such an impression on Hans that he believed his thoughts about his imminent death must have been somehow transmitted miles away. He became determined to find out how the brain transmits “psychic energy,” which eventually led to the invention of EEG for recording electrical activity in the human brain.

  The EEG records the synchronized electrical pulses from billions of neurons in the form of brainwaves. The number and magnitude of the electrical spikes produced depends on the task we are doing, such as active thinking, dreaming, sleeping, or meditating. It defines how alert we are. When sleeping, fewer neurons are active and so brainwaves are slow with high amplitudes. In activities like reading or calculating, more neurons are active and brainwaves are fast with lower amplitudes. The higher the intensity and speed at which our neurons are firing, the faster our EEG brainwaves, the more alert we are, and of course, the faster we can process sensory information. As we shall see, this is a crucial factor in how fast we experience the speed of time. Scientists use brainwave recordings to assess the brain’s overall information processing speed. The quicker you react to a stimulus, the more intense electrical activity is inside your brain. Consequently, people with faster brainwaves have quicker reaction times and faster information processing speeds compared to people with slower brainwaves. 14, 15 They are also generally quick thinkers, impulsive, hyper-sensitive, emotional, and highly stimulated compared to those with slower brainwaves who are described as calm, cautious, steady, and slow.

  “The higher the intensity and speed at which our neurons are firing, the faster our EEG brainwaves, the more alert we are, and the faster we can process sensory information”

  Brainwaves and the level of electrical activity inside the brain are also important to what psychologists call “psychomotor speed.” It simply means being able to coordinate thinking fast with doing something fast, like driving a car. While driving, you are constantly looking around and monitoring your relationship to other cars, pedestrians, and that cat attempting to commit suicide by crossing the road. At the same time, you are pressing the bra
ke or accelerator and turning the steering wheel to navigate to your destination. Your brain does all that on autopilot in a smooth, subconscious way. Psychomotor speed is also important in our ability to interact. When you are listening to what someone is saying, you are processing and deciphering sounds before you receive the next stream of sound bites. In older people, a slower psychomotor speed makes it harder for them to understand and follow conversations. That is because psychomotor speed depends on the overall collective action of brain neurons, which tends to decline with age.

  The brainwaves therefore act as a sort of an “internal clock” to regulate the pace at which sensory information is processed. As we shall see in a subsequent chapter, the level of innate electrical activity and brainwaves also helps to define certain traits of our personality, such as being an introvert or extrovert, a morning or a night person, our patience or impulsiveness, and how easily we get bored. These traits affect the speed at which we experience time as well.

  Recap

  To sum up what we have covered so far, our brain is in the business of detecting motion and controlling movement by capturing and processing sensory information in a specific order so that the world makes sense to us. This processing takes a fraction of a second, which is why we are always lagging slightly behind reality. The brain’s electrical activity and amount of neurotransmitters determine the speed at which our brain absorbs and processes sensory information. This brain information processing speed can be assessed by measuring reaction times and performing psychomotor speed tests. It can also be measured by the amount of electrical activity produced by neurons, displayed as brainwaves in EEG scans. This electrical activity reflects the state of our brain’s consciousness and alertness, from fully awake to fully asleep, and as we shall see next, it defines the essence of our time experience. With this basic understanding of the inner workings of our brain, we are now ready to look at how our ability to detect the ever-changing world around us defines our sense of time. You will have to bear with me through this next chapter, which is slightly longer, but I promise it is worth the effort.