Archive for March, 2014

Choice Reaction Time – are we really that simple ? Part 2

Part 2

Following on from February’s blog here is part two, what I have attempted to do here is convey the understanding that some ideas should be thoroughly examined before we take them as fact.


If the above was not enough evidence there are some that take the basic idea of CRT and expand it to use a doubling rule.   In citing this rule they believe that every decision over and above your first choice will double the time taken to react.   A simple piece of mathematics will help us here.  Choosing between two choices takes approximately 300 milliseconds (ms), add another choice and we get 600ms, another 900ms, another 1 second, 200ms etc – you get the concept I’m sure.    What we have is 1.5 seconds to choose between 6 choices, if this were the case, then not only would we see a fantastic staggering effect when it comes to most highly skilled sports like motor racing, MMA, tennis, football, the list can go on and on, we would also in all probability not be the dominant animal on the planet today, as those 1.5 seconds to make a choice between 6 strategies and actions would have made us food rather than the hunter.

After Hick’s Law came the Power Law of Practice (“PLP”).   In 1980, Newell, Allen and Rosenbloom published a paper that explored the subject of practice and the performance improvements that it creates along with the supporting mechanisms that allow the improvement to become embedded in the behaviour of the individual.  This research considered the chucking theory of learning as a means to explain some of the outcomes of performance that relies on practice. They wanted to confirm the empirical reality that this law was applicable to learning in general rather than just being restricted to skill. The PLP is usually associated with perceptual-motor skills. Before I move on with their research it’s important to understand a little more about the processes involved in learning skills.

The development of perceptual-motor skills begins early in childhood and continues throughout life, providing that the adult individual continues to expand their skill set. There are three stages to this process of development.

  1. Cognitive
  2. Associative
  3. Autonomous

The first stage looks at what is needed to perform a move or task.   This stage requires a certain understanding of the action that is to be learned.

At the second stage, practice is required; another term for this could be “training”, where an individual trains a move or sequence of moves over and over again.

The final stage is embedding the moves into the subconscious so that they can be performed without having to pay attention to any procedures that need to occur. The aim here is to produce speed and accuracy, anything other than this would revert itself back to stage two.


Any hand eye coordinated movements fall into the category perceptual-motor skills, other examples would be body movement and control, which includes bilateral movement, postural formation and control, auditory language skills, visual-auditory skills and any martial based activity would fit into this category. Before any of the higher skill levels can be achieved or worked on an infant must first acquire the basics, which include rolling, crawling, standing, walking, running and so on until they have a good overall control of their body. Once this has been achieved, more advanced skills can emerge, such as running and jumping, catching and writing, these all involve motor skill practice. The next explanation needs to focus on the perceptual side of this equation. Perception is harder to define, as it’s the knowing of how to do something rather than the performance of the skill. Perception skill also has to be separated from intellectual skills, these are generally skills that can be written and defined to allow others to follow the instructions and gain an understanding of how a particular skill is performed.  For example, a person could after some explanation write a manual on how to play chess.   Now imagine trying to write a manual on how to ride a bike, the general principles could be written down, but the ‘how’ could not.   It’s the performance of the ‘how’ part that relates to perceptional-motor skills which cannot be gained by simply reading a description of the act. Once these types of skills are internalized they become part of natural behaviour, in other words the skill becomes an ability, which is performed spontaneously without input from the conscious mind and it’s these highly developed perceptional-motor skills that can be learnt and developed with enough volitional practice.   Here we can see the link between the PLP and the perceptional-motor skill ability as over extended periods of time the ability is learned and transferred from a simple motor skill into a perceptional-motor skill. The transference occurs and performance speed increase when practice becomes a habit and not just something that is trained a few times a week and that’s the biggest difference, if an individual is practicing as a result of habitual processes then the behaviour will soon become ingrained, becoming a perception-motor skill.

The research conducted by Newell, Allen and Rosenbloom (1980) into the ubiquity of the Power Law of Practice theory did not fit the simple power law. They concluded that there were systematic shape deviations in the log-log space, in their words “ There exists a ubiquitous quantitative law of practice, it appears to follow a power law. That is plotting the logarithm of the time to perform a task against the logarithm of die trial number always yields a straight line, more or less. We will refer to this law variously as the log-log linear learning law or the power law of practice”.  To summarize their research they found that the law holds for performance measured as the time to achieve a fixed task.   They looked at three learning curves; exponential, hyperbolic and power law. They found that there was a mechanism that was slowing down the rate of learning and those errors in practice decreased with practice and accuracy increased with practice. This was true for different types of learning, which included perceptual-motor skills, perception, motor behaviour, memory and complex routines. This provides evidence that simple basic responses like those that were tested in Hick’s Law, will, along with complex movements, all fall into the category of PLP.  It is therefore a mistake to focus on simple movements to the exclusion of complex ones as both have the same learning capacity according to the law of power learning.

What is evident from the above is that humans have a capacity to learn complex movements and have protracted capability to remember data. This will help to explain the complicated skills that are involved in sports that have complicated routines like playing tennis, boxing, self-defence systems, or actions like typing, playing chess all involve the ability to learn, memories, practice and over time internalise so that the activity becomes a part of the perceptual-motor skill, no longer requiring complex thought processes to maintain the behaviour.

Lets take a look at some more up to date evidence that relates to this work, research by Silva, Cid, Ferreira and Marques (2011) into the attention and reaction time in Shotokan Athletes produced some interesting results. The aim of their study was to analyze the attention capacity and reaction time in Portuguese karate Shotokan athletes.  The participants were physically characterised into weight, height, body mass index and body fat mass percentage and evaluated on Simple Reaction Time (SRT), Choice Reaction Time (CRT), Decision Time (DT) and Distributed Attention (DA).   What they found was that both female and male participants, when tested for SRT, reacted near to the 300 ms mark and that there was no significant difference between the two gender groups. However both the CRT and the DT indicated a significant difference, which was higher in the Dan and 35+-year group than in any other group.  The Dan 35+ group also showed a lower percentage of mistakes. The athletes who had more years of practice and were higher in grade needed more time to react to the stimulus than the younger less qualified individuals, however they made far fewer mistakes in their choices than the other group.

Reaction times have been the subject of study for many years, they were first studied by Donders (1868), the results that were obtained showed that a simple reaction time is shorter than a recognition reaction time, and that the choice reaction time is longest of all and it’s this CRT that Hick studied.

This brings me all the way back to those that blindly quote a small part of Hick’s Law to justify their simplistic approach to human movement and reaction times, knowing how the human body works and how psychology has helped to explain very complex abilities within the brain enables a logical system to be built. One that allows for the complex ability of the human brain and the highly coordinated ability of the body to move in space and time.   Let’s not just sit back and pull the wool over people’s eyes. I have not touched too much on attention, fear or startle reactions that can, in the right circumstances and with the proper training, increase the body’s reaction speed, let alone symmetry or arousal based reactions.  So it’s fair to say that we have come a long way since the early tests of Hick and certainly Ockham in the 14th century. Ultimately, simplicity will always be a part of any system, but it does not have to stop there, correct training on stimulus based reactions will get results, scenario based systems will get results, simple techniques, will get results, what matters is how they are trained and what mental processes are engaged in the practice. So let’s not try to rubbish other arts for the sake of another student and another pound, let’s push the boundaries instead and convey knowledge and skill the best we can.


Jefferys, W H. and Berger, j O. (1992) Ockham’s razor and Bayisean analysis. American Scientist. Vol. 80. No 1 (January-February 1992), pp. 64-72. Published by Sigma Xi, The Scientific Research Society.

Cohen, N. Poldrack, R. Eichenbaum (1997) Memory for items and Memory for relations in the Procedural/Declarative memory framework. Psychology press, an imprint of Erlbaum (UK) Taylor & Francis Ltd.

Darryl W. Schneider, John R. Anderson Cogn Psychol. Author manuscript; available in PMC 2012 May 1. Published in final edited form as: Cogn Psychol. 2011 May 1; 62(3): 193–222. doi: 10.1016/j.cogpsych.2010.11.001

Newell, Allen and Rosenbloom, Paul S., “Mechanisms of skill acquisition and the law of practice” (1980). Computer Science

Department. Paper 2387.

Kosinski, R, J. (2010) A Literature review on Reaction Time. Updated September 2013,. Accessed on 17-02-2014 @

Silva, C. Cid, L. Ferreira, D. and Marques, A. (2011) Attention and Reaction time in Shotokan Athletes. Published Revista de Artes Marciales Asiaticas (2011), vol, 6 issue 1, p141 16p. accessed on 17-02-2014 @

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