Temporal occlusion paradigmThe temporal occlusion paradigm is a method which requires participants to guess “what
happens next” when asked to view video or film sequences in which key sport-related
information has been occluded deliberately (e.g., by disguising the ball flight-path). In an
ecological variation of this method, liquid crystal occlusion glasses may be used to
replicate film occlusion procedures in actual sport settings. For example, a tennis player
may be asked to wear such glasses while receiving a serve on court. Both variations of
this paradigm are especially useful for assessing expert-novice differences in advance cue
usage (A.M.Williams, 2002b). For example, a top-class tennis player can guess which
side of the court his or her opponent is likely to serve to by making predictions from the
direction of the server’s ball-toss. Thus a right-handed server tossing the ball to his or her
right will probably swing the serve to the right of the receiver. The occlusion paradigm
has also been used to study how soccer goalkeepers anticipate the direction of penalty-
kicks against them in the actual pitch environment. Early anticipation of the direction of a
penalty-kick is vital as goalkeepers have less than half a second to decide which way to
dive in an effort to save the shot. Thus researchers at the Australian Institute of Sport in
Canberra have used occlusion goggles with goalkeepers in an effort to vary the amount
and type of pre-contact cue information available to them. In this way, the goalkeeper’s
use of early visual cues from the penalty-taker (e.g., his or her posture, foot angle and
arm swing) can be analysed (M.Smith, 2003). From such research, it should be possible
to develop anticipatory training programmes for goalkeepers. Unfortunately, little is
known as yet about the efficacy of instructional programmes designed to improve
athletes’ knowledge of situational probabilities in specific sports (A.M.Williams, 2003).
Before concluding this brief discussion of the laboratory version of the occlusion
paradigm, we need to acknowledge that its fidelity or realism is open to question. For
example, to what extent is watching a video sequence of a tennis serve on a large screen
equivalent to being on the receiving end of it on court during windy conditions? A
detailed discussion of the advantages and disadvantages of this technique may be found
in A.M.Williams et al. (1999).
Eye-tracking technologyIf the eyes serve as windows to the mind, then the study of eye movements can provide
insights into the relationship between “looking” (or visual fixation) and “seeing” (or
paying attention). Two main types of eye movements have been identified (Kowler,
1999). On the one hand, saccadic movements are conjugate, high-speed jumps of the eyes
which shift people’s gaze from one location to another (e.g., notice how your gaze is
moving from one word to the next while you read this sentence). On the other hand,
smooth pursuit eye movements help people to focus on a given target (e.g., a ball) during
the intervals between the saccades. These smooth pursuit movements are important
because they enable perceivers to compensate for any displacements on the retina that
may be caused by variations in either head or object position.
A variety of eye-movement registration techniques have been developed for use in
sport settings (see A.M.Williams, 2002a). One of the most popular of these approaches is
the Applied Science Laboratories’ (ASL) 5000 SU eye-tracking system (see Figure 6.3).
What lies beneath the surface? Investigating expertise in sport 165