Schema Theory

Understanding and using Schmidt’s Schema Theory

Schmidt’s Schema Theory tries to explain how we learn and perform ‘discrete perceptual motor skills’. Discrete skills are skills that take a short time to perform and have a clear beginning and end (the ‘discrete’ part). They involve using our senses to understand what is happening (the ‘perceptual’ bit) and then using our bodies to take action (the ‘motor’ bit).

Schema Theory attempts to overcome some of the limitations of earlier theories of motor learning. Closed-Loop Motor Control Theory (Adams 1971), only works with simple and slow limb-positioning movements such as balancing on a beam. It emphasises the role of continuous intrinsic feedback. This feedback is used to modify the movement produced through comparison of the stored memory trace with the on-going perceptual trace.

Fast or ballistic movements, such as a tennis serve, only provide feedback after completion of the movement and therefore intrinsic feedback is not readily available and there is no time for it to help modify the action. So an Open-loop Control Theory was developed for these ballistic actions.

Schema Theory addresses another problem; the idea that each skilled action we have learned requires its own individual Motor Programme. Given that we can learn a vast number of individual actions, there is the question of how can people store so many Motor Programmes in their long-term memory.

Another aspect of movement that was difficult to explain was how people could produce a correct action even though they had never performed that particular set of movements before. Such actions can be called ‘novel skills’ and can be exemplified by performers producing successful responses in situations they have never encountered.

Schmidt’s simple idea was that in many sports we hardly ever repeat exactly the same action. Even considering just one action, like a forehand drop shot in badminton, the shuttlecock is always unique in its height over the net, oncoming trajectory, how far it has dropped before you play it, and so on. We also vary our intentions of how to hit the shuttlecock; faster or harder, or to place the shot left or right. Even when two shots look identical (high forehand serves for example), they will still be slightly different.

So if most shots are unique actions then what do we learn that makes us more skillful? Most definitely it is not a fixed pattern of instructions to muscles, that would not allow for the variations in skills that we see.

Schmidt’s suggested that to perform a skill we need three things:

1. A Generalised Motor Programme

2. Recall Schema; and

3. Recognition Schema.

A Generalised Motor Programme is the basic form of our movements. It’s the basic ability to play a forehand drop shot, to kick or catch a ball. It’s called ‘generalised’ because the programme doesn’t just produce one specific motion. It can generate a variety of similar actions, such as forehand drop shots at a variety of heights or with varying amounts of power.

The theory is that the exact action produced by a Generalised Motor Programme is driven by specific circumstances (e.g. required speed, height), which are fed to the Generalised Motor Programme by the second bit of the theory, the Recall Schema. Recall Schema are simple ‘bits’ of information that are used to adjust the Generalised Motor Programme.

The Recall Schema provides adjustments to the Generalised Motor Programme after understanding the situation you are in (initial conditions) and your intentions (response specifications). For example, if your opponent has remained at the back of the court and is positioned more to your forehand side, then a Recall Schema will feed adjustments of direction and speed to a Generalised Motor Programme for you to move into position and to play a drop shot to your opponents’ open side of the court.

The Recognition Schema is what allows you to know when you’ve made an error. These are the results of the actions; the response outcomes gained though our extrinsic feedback; mainly knowledge of results. The other recognition schema are the sensory consequences, which are how the skill felt, based on our kinesthesis.

So, according to Schmidt, four things are stored in memory after an individual generates a movement:
1. The initial conditions of the movement, such as the proprioceptive information of the limbs and body.
2. The response specifications for the motor programs, which are the parameters used in the generalised motor programme, such as speed and force.
3. The sensory consequences of the response, which contain information about how the movement felt, looked and sounded.
4. The outcome of that movement, the response outcome, which contains information of the actual outcome of the movement with knowledge of results (KR).

This information is stored in components of the motor response schema, which include the recall schema and recognition schema. The recall and recognition schema are linked together, as they use the relationship between the initial conditions and response outcomes. They differ in that recall schema is used to select a specific response with the use of response specifications. Recall schema are used prior to the action response.

Recognition schema are used to evaluate the response with the sensory consequences; they are used during and after the response. Throughout a movement, the recognition schema is compared to the expected sensory information (e.g., kinesthetic and extrinsic) from the ongoing movement to evaluate the efficiency of the response. If the response outcomes are not perfect, the schema are then modified based on the sensory feedback and knowledge of results.

As a simple example of how schema work, get students to attempt a novel skill. Throwing an object (a ball of paper) into a waste paper bin is simple and satisfies most health and safety requirements.

When faced with this skill, the student will select a generalised motor programme to accommodate the requirements of the skill. They could throw underarm/overarm/like a dart/like a javelin/left-handed/right-handed – they decide

They will then decide what adjustments to make to the generalised motor programme based on the initial conditions; how much does the paper weigh, how far do they have to throw the paper, what angle to release the paper, etc. They will also consider the response specifications; how much power is required, how much force needs to be generated, what flightpath is required, etc.

These recall schema are used to adjust the generalised motor programme to produce a suitable movement sequence to achieve the desired outcome.

The performer then attempts the skill. Whether successful or not, the sensory consequences; how did the movement feel, are remembered as a comparison to the expected sensory consequences. Similarly the response outcomes, including detail such as the flightpath, the angle of entry to the waste paper bin, etc. are then stored in memory.

The recognition schema of sensory consequences and response outcomes are then used as a basis on which to make adjustments to the generalised motor programme for a second attempt at the skill, which invariably is more accurate than the first attempt. Subsequent attempts refine the generalised motor programme by the recall schema adjusting it.

In order to learn discrete perceptual motor skills, we first need to develop a generalised motor programme. This needs to be as simplistic as possible and therefore the suggestion is that beginners should learn fundamental or simple skills before sport specific skills. This will involve some trial and error, which is important as the errors prompt adjustments, especially to the Recall Schema.

The more you practise the generalised motor programme the more you relearn/adjust the Recall Schema. Remembering that skills are rarely performed in exactly the same way each time, the more variations that occur, the better for the generation of recall and recognition schema. Performing the skill gets easier each time; the generalised motor programme actually evolves.

Exam-type questions tend to fall into three main categories:

• Those that ask about the four main sources of information used during a skill: initial conditions, response specifications, sensory consequences and response outcomes and what they actually mean – what’s happening; what do I need to do; how did it feel; what happened?
• Those that ask to distinguish the components of either the recall or the recognition schema and how/when they work – recall before and recognition after skill attempt
• Those that ask how to make sure suitable schema develop – learn simple skills first; vary practices; develop recall schema

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