1. ANTICIPATION

2. Learning objectives understand what is meant by interceptive actions
understand how information processing theory explains interceptive actions
understand how action systems theory explains interceptive actions
understand the nature and role of perceptual anticipation in skilled performance
understand how information processing theory explains perceptual information
understand how action systems theory explains perceptual anticipation
understand the difficulties of carrying out research into anticipation
understand the main research findings into anticipation
have a basic knowledge of the key developmental issues

3. Interceptive actions
Hitting a tennis ball, kicking a soccer ball or catching a netball are all examples of interceptive actions
Punching someone in boxing is an interceptive action
Avoiding interception is a form of interceptive action
e.g. avoiding a punch in boxing

4. Information processing theory and interceptive actions
Poulton (1957) called the making of interceptive actions coincidence anticipation
Coincidence anticipation = effector anticipation plus receptor anticipation
Effector anticipation refers to how long the individual thinks it will take them to move their limbs in order to make the interception
Receptor anticipation is how long the person thinks that it will take for an external event to happen
It is a working memory task
Depends greatly on LTM store of similar situations
Pattern recognition plays a major role

5. Action systems theory and interceptive actions
Light waves from the person’s eyes to the object to be intercepted and back again provide information about the line and speed of flight
We subconsciously ‘calculate’ tau () or time to contact
The rate at which the size of the image of the object on the retina increases provides all the necessary information to calculate
Lee (1976) showed that the inverse of the relative rate of expansion of the retinal image gives an accurate measure of 
When contact is imminent, the object provides an affordance to make or avoid contact
Perception-action coupling allows the interception to be made or avoided

6. Criticisms of the  hypothesis
The  hypothesis is based on the assumption that the speed of the approaching object is constant
In real life, it is not
It normally slows due to various resistances in the atmosphere
Lee claimed that the individual automatically takes this into account and, in such situations, determines what he calls tau dot (̇ )
̇ is the rate of change in  itself
the person does not calculate  once but does so ‘on-line’, i.e. calculates the continuous rate of change in 

7. Catching ‘skyers’ and ‘fly balls’
Michaels and Oudejans (1992) claimed that fielders aim to maintain a ‘constant bearing angle’ between their head and the ball
This eases the calculation of ̇
As we do not catch with our eyes, a late second interceptive movement is necessary in order to get the hands or glove into position to make the catch
Lenoir et al. (1999) claimed that fielders attempt to maintain a constant bearing angle between the hands (or catching mitt) and the ball
Thus only one calculation is needed
When the ball is to be intercepted by say a racquet, as in tennis, or a foot, as in soccer, the bearing angle is kept between the racquet (or foot) and ball
López-Moliner et al. (2007) claimed that  and ̇ are supplemented by knowledge of the object to be intercepted

8. Perceptual anticipation
Perceptual anticipation is the ability of the performer to predict upcoming events based on partial information
It is vital in situations that require a decision to be made in faster than one reaction time
It also plays a major role in the way we make decisions when not under time pressure
Allows us to plan ahead

9. Information processing theory and perceptual anticipation
A working memory task
Relies on large LTM store
Pattern recognition is very important

10. Ecological psychology and perceptual anticipation
All necessary information is in the environment
Biomechanical information allows pattern recognition
Affordances are present
These are obvious as long as we know the aims of the game
We do become attuned to these affordances through practice

11. Research paradigms in perceptual anticipation
Temporal occlusion
Comparison of experts and novices watching videos and having to decide what was going to happen when the video is stopped before or just after a key point (e.g. racquet-ball contact when watching a serve in tennis)
Spatial occlusion
Comparison of experts and novices watching videos and having to decide what was going to happen when body parts or equipment (e.g. the racquet in badminton) are occluded
Participants have to mark on a map where they think the ball would have landed
Some paradigms have the participant make a simulated movement

12. Visual search research paradigms in perceptual anticipation
Tracking eye movements of experts and novices while they watch a video and have to make an anticipatory decision at a chosen point
Eye-mark (or eye-tracking) recorders are worn
Can be used in real life situations
Scan paths, fixation locations and durations can be measured
Dependent variables can be verbal or motor (make some kind of movement)

13. Research results Very early cues can be used to aid anticipation
Often pre-ball release/contact by an opponent
Decisions are not always ‘all or nothing’ but the person continues to monitor the situation and make changes ‘on-line’
Experts better than novices, and to lesser extent intermediate level performers, when using the early cues
Expert-novice differences in number of fixations on key parts of the display, scan paths and lengths of time focusing on key points
Experts better in real life situations than in video simulations

14. Development and anticipation: interceptive actions
By eight months infants catch objects moving along the ground at 125 cm/s
Changes in infancy are due to developments in the sensory and motor cortices, and physical development
Later changes are greatly affected by experience
By 3 years children can make a catch using arms and body
By 5 years children can catch a small ball using hands only
By 6 years they are capable of producing a mature catching action
By 6-7 years the child can hit a stationary ball with a mature pattern
Age at being able to hit a moving ball depends on experience and varies greatly

15. Development and anticipation: perceptual anticipation
Information Processing theorists and ecological psychologists agree that ability is dependent on cognitive development and experience
According to Information Processing theorists, everything is dependent on
Working memory
LTM store
According to ecological psychologists everything is dependent on
Attunement to affordances