Using Task Complexity Wisely

Task complexity is critical part of learning process and motor learning researchers have used a classification system to act as a guide for clinicians and trainers to organize the learning environment. 

Body motion only. Low complexity, but perhaps challenging for a new learner. 

Body motion only. Low complexity, but perhaps challenging for a new learner. 

Motor learning researcher, Ann Gentile, generated what is called a taxonomy of skills which serves as a working model in order to understand how the complexity of a task is staged.  

Her two-dimensional classification system is organized according to relationships of the task at hand and describes sixteen categories of skills that include not only the function of the task itself, but the conditions under which the task is being performed.  She arranges the action function into two broad categories: body stability, which means the body does not change locations, and body transport, whereby the body does change locations.  For golfers, the body is stable during the swing so we don’t have to worry about adding the complexity of transporting our bodies while swinging (unless, of course, you are making a “Happy Gilmore” swing).  Within these two broad categories she adds whether or not an object is being manipulated at the same time. Golf always involves object manipulation by nature- you need a club to play golf.   The addition of the club increases the skill complexity and difficulty.  Therefore, if an instructor wanted to reduce difficulty for a learner, they would take away the club.

In addition to the function of the action (which is only one part of this two-dimensional taxonomy) is the consideration of the environmental context.  This is the space around the individual when they are performing the movement and it is divided into two categories: regulatory conditions and intertrial variability.  Regulatory conditions refer the specific features in the environment which might effect the movement.  In golf, regulatory conditions would include the lie of the ball and whether it is buried in deep rough or sitting on a cart path.  The golf course could be familiar or new.  Other examples might be the wind and how it effects a player’s balance, the course conditions, uneven lies, or hitting out from under a branch.  The degree of difficulty increases as these regulatory conditions increase. Intertrial variability means the regulatory conditions change from one trial to the next.   This part is particularly important area for golf instructors to pay attention.  If a player is hitting the same shot with the same regulatory conditions one after the next, there is no intertrial variability.  An example of this would be hitting to the same target on the practice range with the same club.  Or hitting the exact same shot on the golf course from the same place.   To involve intertrial variability, the player adjusts those conditions from one swing to the next.  On the golf course, there is always intertrial variability.  Very seldom is a player faced with exactly the same shot twice in a row.  On the range, unless the target or the club or the lie are changed, there is no intertrial variability .

According to Gentile’s taxonomy, the number of variables the performer needs to pay attention to and the specific elements in each category adds up to how demanding the task will be for the performer.  The simplest skill when learning golf is to make a movement without the club.  The level of complexity is increased when a club is added.  With club in hand, there is an enormous room for changing the degree of difficulty based on how complex the task it.  The range could start with small and simple (such as a putting stroke) to big and complex (like the full swing).  The amount of manipulation taught should be considered carefully as degree of difficulty makes a big difference with a new learner.

Gentile’s taxonomy is a good starting point for understanding the break down in motor skill and for evaluating a performers movement capabilities and limitations.  As golf instructors we can use this as a guide to diagnose deficiencies by changing the conditions in the environment and or changing the movements. The assessment should evaluate the skill from simple to complex such as putting to chipping to full swing.  It also serves as a systematic approach to determining how well the performer can function in various levels of difficulty and complexity. 

As an example, Sally was able to hit pitch shots from the practice area on soft grass and a flat lie.  But when she moved to the golf course, she realized that she needed a shot that required a smaller swing than she had been used to in practice (so she had to adjust her object manipulation) and the lie she was standing on was now uphill (her regulatory conditions were unfamiliar).   The demands on Sally were higher than she was ready for leaving her unable to perform giving us one answer as to why she couldn’t bring her “range game” to the course.


Gentile, A. M. (2000, 1972). A Working Model of Skill Acquisition with Application to Teaching. Quest, Vol. 17, Iss. 1. 

Gentile, A.M. (2000). Skill acquisition: Action, movement, and neuromotor processes. In J.H. Carr, & R.B. Shepherd (Eds.), Movement science: Foundations for physical therapy, 2nd ed., pp. 111-187. Rockvill, MD: Aspen.