Information

Why does a distraction cause a longer reaction time?


Does it have something to do do with the fact that the individual isn't concentrating on reacting to the stimulus, so it takes longer for it to be processed? How can this be out in terms of neurones and neurological pathways? what is happening for there to be a delayed reaction time?


When one processor is running two processes, A and B, it is not running them simultaneously: it is switching between them. The switching between A and B takes time---hence the delay.


I am not sure which sort of answer is expected. The minimal answer to that would be that the more distracted you are the longer it needs to sample the stimulus space of interest as you are sampling another distracting stimulus simultaneously with your limited sensory capabilities.

Cognitive tasks get just more complex with distraction as the brain cannot know which features (of the full stimulus space from all the sensory modalities) to take into account and therefore needs to sample more data to find out which of the inputs matter for the specific task. In most of natural situations the inputs match together in terms of experienced stimulus combinations (visual field and sound while walking for example) except for surprising situations that require to alter ones attention (a sound that does not match to the visual scenery is unexpected and might be important to check for danger). To decide whether the system can ignore such parts of the input requires computation and computation takes time. I don't think it is useful to tackle the question in terms of delayed signaling along specific neurons or pathways. The signaling itself is more or less of constant speed and not directly altered by distraction. Of course on a very basic level an increased adrenaline level or similar due to distraction might affect the "weights" of certain basic pathways as one is pushed into another state. In such cases therefore it requires the system to compensate those changes with respect to the actual task of interest as it might be biased to different reaction scheme that is not useful for the specific task.

Actually our brains are very good in focusing on specific parts of the inputs that are important for a task (i.e. cocktail party problem) but still it needs more time to correct the erroneous parts in the presence of distraction. In terms of a simple Hopfield network that does pattern completion distraction would be like an increase of the noise level which leads to a higher number of iterations required for convergence while the speed of signal transmission from neuron to neuron was not altered.


Smartphones make people distracted and unproductive

Thinkstock

Opinion by Mike Elgan

Silicon Valley is draining away the economy's most precious resource for its own benefit.

OK, I'd better explain that.

The economy's most precious resource is human attention — specifically, the attention people pay to their work. No matter what kind of company you own, run or work for, the employees of that company are paid for not only their skill, experience and work, but also for their attention and creativity.

When, say, Facebook and Google grab user attention, they're taking that attention away from other things. One of those things is the work you're paying employees to do.

As a thought experiment, imagine that an employee who used to pay attention to your business eight hours each day now pays attention only seven hours a day because he or she is now focusing on Facebook during that last hour. You're paying the employee the same, but getting less employee attention for it.

Facebook is getting that attention - and monetizing it with additional advertising dollars. In short, Facebook CEO Mark Zuckerberg is transferring wealth from your company to his. And he's doing it every day, and constantly increasing how much he takes.

Of course, it's far more complicated than that. Employees are distracted by smartphones, web browsers, messaging apps, shopping sites and lots of social networks beyond Facebook. More alarming is that the problem is growing worse, and fast.

One data point from the analytics firm Flurry found that U.S. users are spending more than five hours per day using their smartphones and that the time spent using mobile apps increased 69% in a single year (from 2015 to 2016).

The time spent on social networks is also growing fast. The Global Web Indexsays says people now spend more than two hours each day on social networks, on average. That extra time is facilitated by smartphones and apps.

If you're suddenly hearing a lot of chatter about the deleterious effects of smartphones and social networks, it's partly because of a new book coming out Aug. 22 called iGen. In the book, author Jean M. Twenge makes the case that young people are "on the brink of a mental health crisis" caused mainly by growing up with smartphones and social networks. (You can read an excerpt in the September issue of The Atlantic - which, incidentally, is now owned by Steve Jobs' widow, according to this article in The Washington Post, which, incidentally, is owned by Amazon CEO Jeff Bezos. We'll save the topic "tech money buying old media" for a future column.)

These depressed, smartphone-addicted iGen kids are now entering the workforce and represent the future of employers. That's why something has got to be done about the smartphone distraction problem.

But wait! Isn't that the same kind of luddite fear-mongering that attended the arrival of TV, videogames and the Internet itself?

It's not clear. What is clear is that smartphones measurably distract.


What Factors Affect Reaction Time?

Forces that alter or interfere with perception – including state of attention, muscle tension, age, practice, distractions and physical fitness – affect reaction time. Because reaction time depends on the ability to perceive stimulus and respond, these factors affect the speed of responses and skew judgment about choosing between responses.

Much experimentation in reaction time studies human response to traffic and other rapidly changing situations. In those cases, subjects must first prove that they can perceive a stimulus and then react to it. A subject receives a rating according to his raw reaction times factored against a base state calculated from preparation for testing, life experience, age, physical fitness and state of attention.

Scientists commonly test to measure reaction times for four different types of reactions: reflex, simple, complex and discriminative. Because reflex reactions, such as eye blinks, are instinctive, they usually take the shortest time. Simple reactions, which also have short reaction times, are those to ordinary, everyday stimuli, such as the response to a traffic light turning from red to green. Complex reactions, where a subject has to choose among multiple responses, have longer reaction times and involve choosing the appropriate response based on experience, but without advanced planning. The most complex reactions with the longest reactions times are discriminative reactions, where subjects must choose from multiple responses which are not practiced or habitual.


Reaction Time Ruler

In this activity, the students participate in a simple ruler drop experiment and learn about the body’s response behind it.

When your friend drops the timer in the experiment, you see it start to move. A nerve signal travels from your eye to your brain then to your finger muscles. Your finger muscles move to catch the timer. The whole process takes between 150 and 220 milliseconds.

The neural pathway involved in a reaction time experiment involves a series of neural processes. This experiment does not test a simple reflex. Rather, this activity is designed to measure the response time to something that you see.

Catching a dropped ruler begins with the eye watching the ruler in anticipation of it falling. After the ruler is dropped, the eye sends a message to the visual cortex, which perceives that the ruler has fallen. The visual cortex sends a message to the motor cortex to initiate catching the ruler. The motor cortex sends a message to the spinal cord, which then sends a message to the muscle in the hand/fingers. The final process is the contraction of the muscles as the hand grasps the ruler. All of these processes involve individual neurons that transmit electrochemical messages to other neurons.

A person’s reaction time depends on a couple of things that can be improved and a couple that cannot.

Practice does make perfect because you can create a “muscle memory” that means you do not have to think so much to catch the ruler. You can take the time it takes to decide things out of the equation. Much of the time it takes you to react to the ruler dropping is the time it takes electrical signals to travel along your nerves. Moving at about 100 metres per second, a signal telling a finger to move has to travel from your brain down your spinal cord and into your arm. Signals for muscle control generally move faster than other ones. (Pain signals for example, move very slowly, often less than one metre per second). But these signals are “involuntary” which means that no matter how hard you try, you cannot control how quickly they occur.

The distance the reaction timer travels before you catch it has been converted to time using the equation d=1/2at² where a is the acceleration due to gravity.


As We Age, Loss of Brain Connections Slows Our Reaction Time

Have you ever wondered why kids seem so much better at video games than adults? A University of Michigan study suggests that, as we age, our brain connections break down, slowing up our physical response times.

According to the study, older adults seem to have excessive &lsquocross-talk&rsquo between the two hemispheres of the brain. This cross-communication occurs through a brain structure called the corpus callosum, which can act as either a bridge or a dam between brain hemispheres.

The bridge action is very important during two-sided motor skills and certain cognitive functions. However, during one-sided motor skills requiring strong focus from only one side, the corpus callosum switches roles and serves as a sort of dam between hemispheres.

As we age, breakdowns in the corpus callosum occur, breaking down the dam effect, and causing more cross-talk to occur between hemispheres, even when it&rsquos not particularly useful.

The study is the first known to show that this cross-talk happens even while older adults are at rest, says Rachael Seidler, lead study author and associate professor in the University of Michigan School of Kinesiology and department of psychology.

This resting cross-talk suggests that it is not helpful or compensatory for the two halves of the brain to communicate during one-sided motor movements because the opposite side of the brain controls the part of the body that is moving. So, when both sides of the brain talk simultaneously while one side of the body tries to move, confusion and slower responses result, Seidler says.

Previous studies have shown that cross-talk in the brain during certain motor tasks increases with age but it wasn&rsquot clear if that cross-talk helped or hindered brain function, says Seidler.

&ldquoCross-talk is not a function of task difficulty, because we see these changes in the brain when people are not moving,&rdquo adds Seidler.

In some diseases where the corpus callosum is very deteriorated, such as in multiple sclerosis, a person will have &ldquomirror movements&rdquo during one sided-motor tasks, in which both sides of the body move in concert because there is too much communication between the two hemispheres of the brain, Seidler says. These mirror movements can also be seen in very young children before the corpus callosum is fully developed.

During the study, scientists gave joysticks to adults between the ages of 65 and 75 and measured and compared their response times against a group approximately 20 to 25 years old.

Researchers then used a functional MRI to image the blood-oxygen levels in different parts of the brain, a measurement of brain activity.

&ldquoThe more they recruited the other side of the brain, the slower they responded,&rdquo Seidler says.

Researchers believe there is hope, however, and just because we all get older, it doesn&rsquot have to be our fate to react slowly. Seidler and her colleagues are developing and piloting motor training studies that might rebuild or maintain the corpus callosum to limit overflow between hemispheres, she said.

A previous study done by another group showed that doing aerobic training for three months helped to rebuild the corpus callosum, she said, which suggests that physical activity can help to counteract the effects of the age-related degeneration.

Seidler&rsquos group also has a study in review that uses the same brain imaging techniques to examine disease-related brain changes in Parkinson&rsquos patients.

The study appeared in the journal Frontiers in Systems Neuroscience.


Speedy Science: How Fast Can You React?

Introduction
Think fast! Have you ever noticed that when someone unexpectedly tosses a softball at you, you need a little time before you can move to catch it (or duck)? That's because when your eyes see an incoming signal such as a softball, your brain needs to first process what's happening&mdashand then you can take action. In this activity, you can measure just how long it takes for you to react, and compare reaction times with your friends and family.

Background
You may not realize it, but when your senses pick up clues from the outside world&mdashthe smell of baking cookies, the color of a stoplight, the rrrring! of an alarm clock&mdashit takes a fraction of a second for you to recognize that signal and respond. During that time your brain receives information from your senses, identifies a possible source, and allows you to take action. The jam-packed fraction of a second is called your reaction time.

This activity teaches you about your brain's reaction time, but it also relies on the laws of physics. Specifically, you can calculate your reaction time using our handy chart, which is based on how quickly a ruler falls. How do we know how quickly your ruler will fall? Gravity pulls all objects toward Earth's center at the same speed. If you want to try this out at home, try dropping a tennis ball and a basketball from the same height: They should both hit the ground at the same time!

Materials
· Ruler (inches or metric)
· Paper
· Pencil
· Chart (below)

Line Where Partner Pinched Ruler
(inches | centimeters)
Reaction Time
(seconds | milliseconds)
2 in. 5 cm. 0.1 sec. 100 ms.
4 in. 10 cm. 0.14 sec. 140 ms.
6 in. 15 cm. 0.17 sec. 170 ms.
8 in. 20 cm. 0.2 sec. 200 ms.
10 in. 25.5 cm. 0.23 sec. 230 ms.
12 in. 30.5 cm. 0.25 sec. 230 ms.
17 in. 43 cm. 0.3 sec. 300 ms.
24 in. 61 cm. 0.35 sec. 350 ms.
31 in. 79 cm. 0.4 sec. 400 ms.
39 in. 99 cm. 0.45 sec. 450 ms.
48 in. 123 cm. 0.5 sec. 500 ms.
69 in. 175 cm. 0.6 sec. 600 ms.


Preparation
&bull You need to use some math skills in this challenge. To make things easier, we've provided a chart, above, that you can print or copy out on a piece of paper. The basic rule: 100 milliseconds translates into about two inches or five centimeters.
&bull On a clean sheet of paper, write the name of each person&mdashincluding yourself&mdashwho will take part in this experiment. You only need two people for this activity, but it's also great for a group. Leave five spaces below each name.

Procedure
&bull Hold the ruler vertically so that the zero end hangs down.
&bull Ask your partner to stand next to you and place his or her hand below the ruler's zero line, ready to catch the ruler when it falls by pinching it between his or her thumb and index finger. Your partner's fingers should be just below the ruler, but as close as possible to the bottom edge without touching or overlapping.
&bull Tell your partner that you will count from one to five and drop the ruler at some point during the count. Your partner will need to catch the ruler as quickly as he or she can, pinching the ruler between his or her fingers.
&bull Count from one to five and drop the ruler at some point
&bull Your partner should catch and pinch the ruler. How fast did your partner appear to act? Did your partner's fingers pinch near the zero line?
&bull Write down the centimeter or inch line where your partner's fingers pinched the ruler.
&bull Calculate how long it took your partner to respond using the chart provided. Was your partner as fast as you thought?
&bull Repeat the drop four more times for your partner, and record the measurement each time. Does your partner's reaction time change? Are the five reaction times different? Vary when you drop the ruler: For example, you could drop on the count of five first, then drop on two.
&bull Switch tasks and try catching when your partner drops the ruler, then compare your results with the others. Do most people have a similar reaction time? Are older people faster than younger people? Are girls faster than boys?
&bull You can also try a few variations: What happens when you tell your partner when you will drop the ruler? Does reaction time improve with practice?
&bull Extra: Ambidextrous, anyone? Repeat this activity and compare your results when you use your dominant hand&mdashthe hand you write with&mdashand when you use your other hand. Is there any difference between hands?
&bull Extra: Consider adding other distracting sounds and sights&mdashsuch as turning on a TV set or flicking a flashlight on and off&mdashduring the activity. Do your responses slow with so many sensory signals?


Observations and results
Did you and your partner usually catch the ruler around 15 centimeters (six inches)? What took so long?

On average, reaction time takes between 150 and 300 milliseconds. If that sounds like a long time, think about how much has to happen for you to react. When your eye sees the ruler falling, information travels from sensory cells called neurons from the eye to the brain's visual cortex, an area devoted to understanding what you see. Next, the motor cortex&mdashthe part of the brain that directs movement&mdashhas to send signals along your spinal cord and to your arm, hand and finger muscles, telling them to respond in the proper sequence to catch the ruler&mdashquick! That's a lot happening in less than half a second&mdashand a pretty amazing feat!

More to explore:
Experience versus Speed from Scientific American MIND
Brain Brakes Car Faster Than Foot from Scientific American
Reaction Time Test from the Human Benchmark
How fast are your reactions? from the BBC


Easily Distracted?

If you are paid to answer emails or deal with customers all day then this post might not be for you. But if you're someone who often needs to get some thinking done, read on.

An epidemic of overwhelm
People everywhere seem to be experiencing an epidemic of overwhelm at work. I believe it's a function of two things. Firstly it's the amount of information we now process, which our brain may not be used to. I read somewhere that The New York Times on Sunday contains more information than the average 18th century French Nobleman learned in his lifetime (now, if only I could remember where I read that. )

Secondly, we have all these new technologies which are very good at distracting us, which our human habits have not caught up to. The challenge is that we have not realized the true cost of distractions: they use up what is actually a limited supply of attention each day, and make us far less effective if we need to do deeper thinking work. For example, a university of London study found that being always connected impacts your IQ equivalent to losing a night's sleep or taking up marijuana.

Attention is a limited resource
Every time you focus your attention you use a measurable amount of glucose and other metabolic resources. Studies show that each task you do tends to make you less effective at the next task, and this is especially true for high-energy tasks. So distractions really take their toll.

Here's more on this from the book:

Distractions are everywhere. And with the always-on technologies of today, they take a heavy toll on productivity. One study found that office distractions eat an average 2.1 hours a day. Another study, published in October 2005, found that employees spent an average of 11 minutes on a project before being distracted. After an interruption it takes them 25 minutes to return to the original task, if they do at all. People switch activities every three minutes, either making a call, speaking with someone in their cubicle, or working on a document.

Distractions are not just frustrating they can be exhausting. By the time you get back to where you were, your ability to stay focused goes down even further as you have even less glucose available now. Change focus ten times an hour (one study showed people in offices did so as much as 20 times an hour), and your productive thinking time is only a fraction of what's possible. Less energy equals less capacity to understand, decide, recall, memorize, and inhibit. The result could be mistakes on important tasks. Or distractions can cause you to forget good ideas and lose valuable insights. Having a great idea and not being able to remember it can be frustrating, like an itch you can't scratch, yet another distraction to manage.

Remove temptation
So how can we address this?
The answer is quite simple. Once you understand how much energy is involved in high-level thinking like planning and creating, you might be more vigilant about allowing distractions to steal your attention. One of the most effective distraction-management techniques is switch off all communication devices during any thinking work. Your brain prefers to focus on things right in front of you. It's less effort. If you are trying to focus on a subtle mental thread, allowing yourself to be distracted is like stopping pain and enjoying a mild pleasure: it's too hard to resist! Blocking out external distractions altogether, especially if you get a lot of them, seems to be one of the best strategies for improving mental performance. There is no 'trick' to this: you simply must switch things off, or you wont focus.

So part of the solution to managing distractions is quite easy in theory, it just takes some courage. It's also not negotiable: there's no way not to be distracted by distractions, it's built into the brain in the way we pay attention to novelty.

Distractions are not just external though. Here's more from Your Brain at Work:

Awash with activity
As adolescence hits and you become more conscious of an inner life, many people notice that their mind is hard to control. Strange thoughts pop into awareness at odd moments. The mind likes to wander, like a young puppy sniffing around here and there. As frustrating as this tendency can be, it's normal and it tends to stay this way through life. One reason for your wandering attention is that the nervous system is constantly processing, reconfiguring, and reconnecting the trillions of connections in your brain each moment. The term for this is "ambient neural activity". If you were to look at the electrical activity even in a resting brain, it would look like planet earth from space with electrical storms lighting up different regions several times a second.

Trey Hedden and John Gabrieli, two neuroscientists from MIT, studied what happens in the brain when people are distracted by internal thoughts when doing difficult tasks. They found that lapses in attention impair performance, independent of what the task is, and that these lapses in attention involve activating the medial prefrontal cortex. The medial prefrontal cortex is located within the prefrontal cortex itself, around the middle of your forehead. It activates when you think about yourself and other people. This region of the brain is also part of what is called the "default" network. This network becomes active when you are not doing much at all, such as being in between activities while in a scanner. Hedden and Gabrieli found that when you lose external focus, this default brain network activates and your attention goes to more internal signals, such as being more aware of something that may be bothering you.

Driving away from distractions
You might wonder how you ever stay focused. We have specific neural circuitry for this process, though it doesn't work the way you might expect. A key part of maintaining good focus occurs based on how well you inhibit the wrong things from coming into focus.

A common test that neuroscientists use to study the act of focusing is the "stroop" test. Volunteers are given words printed in different colors, and told to read out the color of the text, not the word itself. In the example below, the brain has a strong desire to answer "Grey" for option c., as it's easier for the brain to read a word than to identify a color.

a. Black
b. Grey
c. Grey
d. Black

To not read the word "Grey" requires inhibition of an automatic response. Using scanning technologies neuroscientists have observed people inhibiting their natural responses, and discovered the brain networks that are activated when this happens. There is one specific region within the prefrontal cortex that keeps showing up as being central for all types of inhibition. It's called the right and left ventrolateral prefrontal cortex (VLPFC), and it sits just behind the right and left temple.

The VLPFC inhibits many types of responses. When you inhibit a motor response, a cognitive response or an emotional response, this region becomes active. It appears that the brain has many different ‘accelerators', with different parts of the brain involved in language, emotions, movement, and memories. Yet there is only one central braking system used for all types of braking.

Your ability to use this braking system well, the VLPFC, seems to correlate closely to how well you can focus. It seems that to focus we need to learn to stop ourselves from going down the wrong path. One of the challenges with this process though is that this braking system isn't very effective.

Putting on the breaks
If you were a car company and were building a new type of on-road vehicle you would make sure the braking system was made out of the most robust materials possible, because brake failure is not a happy thing. Well in the case of human brains, the opposite has happened. Our braking system is part of the most fragile, temperamental and energy-hungry region of the brain, the prefrontal cortex. Because of this, your braking system only works at its best every now and then. If cars were built like this you'd never survive your first drive down to the store. All this makes sense when you consider it: stopping yourself from acting on an urge is something you can do sometimes, but is often not that easy. Not thinking about an annoying, intrusive thought at times can be very difficult. And staying focused, well sometimes that appears downright impossible.

Timing is of the essence
So, inhibiting distractions is a core skill for staying focused. To inhibit distractions, you need to be aware of your internal mental process and catch the wrong impulses before they take hold. It turns out that, like the old saying goes, timing is everything. Once you take an action, an energetic loop commences that makes it harder to stop that action. Many activities have built-in rewards, in the form of increased arousal that holds your attention. Once you open your email program and see the messages from people you know, it's so much harder to stop yourself from reading them. Most motor or mental acts also generate their own momentum. Decide to get out of your chair and the relevant brain regions, as well as dozens of muscles, are all activated. Blood starts pumping and energy moves around. To stop getting out of your chair once you start will take more focus and effort than to decide not to get up when you first have the urge. To avoid distractions it's helpful to get into the habit of stopping the wrong behaviors early, quickly, and often, well before they take over.

And here's a big take away from all this. Manage what you focus on.Pay attention to your attention, and stop yourself from getting on the wrong train of thought early, before it takes over. This is the oppositive of being mindless: it's being mindful.

The best way to do that is to practice being aware of your own thoughts, by activating your observer function. How do you do that, when you have a ton of information pouring through your head as you process a hundred emails in the morning? The answer is clear: you can't. If you want to do deeper thinking work, don't start your day overwhelming and exhausting your brain. Start with the tougher work that requires a more focused, quiet mind. Many people have this back to front. If your job is to think, tackle thinking tasks early, and tasks that are relatively 'interesting' such as checking your emails (which means your brain will go there easily) later when you are tired.

So in summary, how do you beat back distractions? Turn everything off. And do your deeper thinking work in the morning while you still have the ability to control your attention. Sounds easy enough. In practice it's tough, but it works.

Next week I will post about the neuroscience of mindfulness, explaining mindfulness in a simple and practical way, and illustrate how being mindful affects the brain in the short and long term.


What is reaction time in sports exactly?

Reaction time describes the time interval between an external signal and your reaction to it. The most simple example of this is hearing a starting pistol and accelerating towards the finish line. Of course, similar situations can be found in all court-based sports where you have to quickly adjust to changing situations.

And, unlike reflexes, where the information goes straight to a muscle from the spinal cord and doesn’t involve the brain, reactions need to be processed first. Thus, your brain decides whether the stimulus is important enough to respond to – and how to do it most efficiently.

Reaction time is dependant on three main factors

In a sports context, a stimulus can be either visual (seeing), auditory (hearing) or kinesthetic (touch) depending on the activity. Once the signal is perceived through the sensory system (part of the nervous system responsible for processing sensory information), your brain quickly processes the information and responds by sending a message down the spinal cord to the right muscles and creates a contraction.

Therefore, your reaction time is a result of these three components working together. If one of them is hindered, your reaction time will be longer as a result. However, bear in mind that since reaction time requires a physical response from your muscles, it is not the same as processing speed, which describes how fast you can detect a signal. Hence, why fast reaction time is often associated with good reflexes.

Different types of reaction time in sports

Reaction time can also be divided into simple reaction time and complex reaction time.

Simple reaction time refers to reacting to a single stimulus and is usually very fast (around 0.13-0.18s). This is due to the fact that there is only one stimulus and one response to it. For example, reacting to a starting pistol during a 100m sprint is a simple reaction time task.

Complex reaction time, also known as choice reaction time or compound reaction time, describes the time it takes to respond to the correct stimulus out of many stimuli and responding to it in the best way possible. However, since the brain receives more information from the environment, it also takes a slightly longer time to process. This is also known as Hick’s law. One example of a choice reaction time is a soccer player who needs to react to the movement of the ball and other players on the field.

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Quicker decision making can slow down the game around you and help maintain balance in sudden situations.

The physiological factors of reaction time in sports

There are a few factors that can affect your reaction time in sports and life in general. These include genetics, sex, age, cognitive abilities, training background and even body temperature. All of these factors have their own impact on how fast your reaction time is and how well you can improve it.

Genetics and reaction time go hand in hand. Unfortunately, reaction time can only be improved around 10-20% outside of these biological factors. This is due to the fact that reaction time is hardwired into our bodies through nerves and therefore impossible to improve. However, there is always that small improvement you can achieve if you’re willing to put in the work.

Sex can also have a small effect on reaction time. On average, males and females have a similar muscular contraction time. However, males show stronger motor responses which result in faster reaction times. One thing to keep in mind is that this data is somewhat old and these differences are becoming smaller and smaller. This is partly due to females having a better opportunity to participate in fast-paced activities like motorsports and eSports.

Age can have a significant effect on your reaction time. In fact, there are signs that your brain’s response time starts steadily declining at age 24 at a rate of approximately 0.5ms/year. However, studies suggest that your ability to detect a signal stays similar even as you grow older while the response time to the signal becomes slightly longer.

Fatigue is a crucial factor in reaction time. This is due to the fact that once your nerves get tired they are not able to send or receive messages as efficiently as before. These factors are especially apparent if you are under severe physical stress or suffering from sleep deprivation. Even substance abuse can have similar effects for your reaction time. Thus, fatigue leads to longer reaction and response times, which can be detrimental in a variety of sports scenarios.

Training background can also have a big effect on reaction time in sports. On average, simple reaction time is between 0.16s to 0.2s among most people. However, top-tier athletes have shown reaction times as low as 0.15s which of course means faster acceleration in very high-intensity sports. However, even the best sprinters cannot go below 0.1s. Reaction time can also be practiced and maintained, but it needs consistent training.

Body temperature also has an effect on your reaction time. According to some studies, the optimal reaction time occurs at higher body temperatures. Furthermore, as the body temperature cools down, your reaction time will become longer as a result.

The faster your reaction time is, the more time you have to process what happens on the field and make the right decision.

The mental and environmental factors of reaction time in sports

Reaction time isn’t just a result of your biology. You see, there are also a few environmental and mental factors that can affect your reaction time in sports. These include alertness and tiredness, some cognitive abilities, the intensity of the stimulus, personal experience and environmental distractions just to name a few.

The complexity of the stimulus itself is one of the main factors in reaction time. This is due to the fact that simple reactions do not need the same mental power as more complex reactions. Additionally, even the perception mechanism of the stimulus plays a part in how fast you can respond. Visual being the fastest way to respond to a stimulus, followed by hearing.

Alertness and fatigue also have a strong correlation in reaction times in sports. Studies have shown that being too tired, too relaxed or even too tense will result in longer reaction times. This means that you must be well-rested, mentally ready and laser-focused during an athletic performance.

Anticipation and experience are also crucial factors for reaction time in sports. This is because you also have to be technically and tactically ready for the stimulus and act accordingly on the field. This means using the skills and experience you have learned in your sport to know when and where the stimulus might occur. Thus, it is easy to see why concentration, observation and split-second decision-making are crucial skills for an athlete.

Some cognitive abilities such as higher IQ have been linked to faster reaction times in some studies. However, the actual mechanism for this is still unclear. One theory is that individuals with higher IQ may show better focus and attention or have more effective information processing in the brain.

Distractions are also common in elite level sports. Sometimes background noises such as whistles, yells or chants may disrupt your thought process and hinder reaction times. In fact, even poor vision can significantly delay your reaction times due to having less visual feedback. Therefore it is all the more important that an athlete can mentally phase out all unnecessary distractions and try to train in well-lit conditions.


INTRODUCTION

The main purpose of athletes and coaches is to achieve the optimal performance during sport events, so knowing about the important factors which have effects on athletic performances, is necessary. Sleep loss can have profound effects on human performance. In the laboratory setting, a variety of performance tasks have been shown to be affected by sleep deprivation [1𠄲] .

Although athletes and coaches believe that adequate sleep is essential for peak performance, there are many situations (e.g. jetlag or anxiety) in which sleep is disturbed prior to an athletic event. Total sleep deprivation (TSD) has been shown to negatively affect many physiological, cognitive, and behavioral measures within the body [3] .

Available literature points to sleep deprivation attenuating a person's ability to perform a variety of psychomotor tasks designed to measure neuromuscular function. Of the measures of psychomotor ability used to assess the effects of sleep deprivation, reaction times, both simple and choice are most frequently reported. For example, sleep deprivation has been associated with longer reaction times and reduced force on a simple and choice reaction time test [4] . Other studies have shown that sleep deprivation ranging from 30 to 64 h influences simple and choice reaction time significantly [5] .

Similar results have been found for tasks that involve higher levels of cognitive functioning. That is, sleep deprivation results in decreased performance characterized by increased lapsing, cognitive slowing, memory impairment, decrease in vigilance and sustained attention and shift in optimum response capability [6,7] . It was shown in a study that there is a relationship between a decrease in levels of attention and total sleep deprivation [8] . Evidence suggests athletes worry about the effects of inadequate sleep on performance [9] , although sleep deprivation on physical performance (e.g. anaerobic power, muscle strength, endurance, physiological responses such as heart rate, ventilation, and oxygen consumption) is not clearly understood [10�] . Rodgers et al [12] reported that 48 hours period of sleep deprivation significantly decreased the physical work tasks requiring 30�% VO2max without affecting anaerobic power. Further, Souissi et al [13] demonstrated that duration of sleepless period may be important as peak power was not affected after 24 hours sleep deprivation but significantly decreased after 36 hours of wakefulness. On the other hand, some studies suggested that sleep deprivation of up to at least 24 h has not been shown to influence physical performance capabilities like muscular strength, and cardiovascular and respiratory responses to exercise [13�] while some studies suggested the temporal change of these abilities [16,17] .

Reaction time and anaerobic power are two important factors affecting the performance of many sports, therefore this study was to investigate one night sleep deprivation (due to being epidemic among athletes) on anaerobic performance parameters such as peak power and mean power obtained from the 30-second Wingate Test and choice reaction time.


New Study Says Texting Doubles a Driver’s Reaction Time

Researchers at the Texas Transportation Institute have determined that a driver’s reaction time is doubled when distracted by reading or sending a text message. The study reveals how the texting impairment is even greater than many experts believed, and demonstrates how texting drivers are less able to react to sudden roadway hazards.

The study — the first published work in the U.S. to examine texting while driving in an actual driving environment — consisted of three major steps. First, participants typed a story of their choice (usually a simple fairy tale) and also read and answered questions related to another story, both on their smart phone in a laboratory setting. Each participant then navigated a test-track course involving both an open section and a section lined by construction barrels. Drivers first drove the course without texting, then repeated both lab tasks separately while driving through the course again. Throughout the test-track exercise, each participant’s reaction time to a periodic flashing light was recorded.

Reaction times with no texting activity were typically between one and two seconds. Reaction times while texting, however, were at least three to four seconds. Worse yet, drivers were more than 11 times more likely to miss the flashing light altogether when they were texting. The researchers say that the study findings extend to other driving distractions that involve reading or writing, such as checking e-mail or Facebook.

The study, sponsored by the Southwest Region University Transportation Center, was managed by Christine Yager, an associate transportation researcher in TTI’s Center for Transportation Safety. Forty-two drivers between the ages of 16 and 54 participated in the research.

In addition to the reaction-time element, researchers also measured each driver’s ability to maintain proper lane position and a constant speed. Major findings further documented the impairment of texting when compared to the controlled driving conditions. Drivers were less able to:

  • safely maintain their position in the driving lane when they were texting and their swerving was worse in the open sections of the course than in barreled sections.
  • maintain a constant speed while texting, tending to slow down in an effort to reduce the demand of the multiple tasks. By slowing down, a driver gains more time to correct for driving errors (such as the tendency to swerve while texting). Speed variance was also greater for texting drivers than for non-texting drivers.

The fact that the study was conducted in an actual driving environment is important, the researchers say. While simulators are useful, the dynamics of an actual vehicle are different, and some driver cues can’t be replicated in a simulator. By using a closed course, researchers can create an environment similar to real-world driving conditions while providing a high degree of safety for the participants.

“Most research on texting and driving has been limited to driving simulators. This study involved participants driving an actual vehicle, “Yager says. “So one of the more important things we know now that we didn’t know before is that response times are even slower than we previously thought.”

The total distance covered by each driver in the study was slightly less than 11 miles. In the interest of safety for both participants and the research staff, researchers minimized the complexity of the driving task, using a straight-line course that contained no hills, traffic or potential conflicts other than the construction zone barrels. Consequently, the driving demands that participants encountered were considerably lower than those they would encounter under real-world conditions.

“It is frightening,” the researchers wrote, “to think of how much more poorly our participants may have performed if the driving conditions were more consistent with routine driving.”

Federal statistics suggest that distracted driving contributes to as much as 20 percent of all fatal crashes, and that cell phones constitute the primary source of driver distraction. Researchers point to two numbers to illustrate the magnitude of the texting while driving problem: an estimated 5 billion text messages are sent each day in the United States, and at least 20 percent of all drivers have admitted to texting while driving.