I spy with my QE - 3.1

Question 1

visual perception

Answer 1

Almost half of the cerebral cortex is devoted to vision-related functions.

It follows then that the neural processes that transform visual information into the representations that allow us to perceive the world and interact within it, are central to brain function.

In sport – vision is by far the most important sense (although auditory and tactile information is also important)

This information is needed to successfully make decisions (anticipate) & perform goal-directed actions (movement)

Question 2

Uiga et al. (2015) - Acquiring visual information for locomotion by older adults

Answer 2

older people focus couple of steps in front

Question 3

eye-tracking

Answer 3

Gaze direction can be calculated by comparing the relative position and the relationship between the pupil (A) and corneal reflection – the glint (C).

Infra- red illumination of the eye produces the ‘bright pupil’ effect (B) and makes the tracking easier

overlaid with video

Question 4

eye movements and gaze control

Answer 4

fixations

saccades

Question 5

fixations

Answer 5

Gaze is maintained on objects or locations for sufficient time to allow information to be processed

Within 3 degrees of visual angle for 100ms or longer

(NB at least 180 ms needed to see an object and initiate a simple movement).

ends when deviate

Question 6

saccades

Answer 6

Eyes move quickly from one location to another

Rapid jumps – bring new part of visual field into foveal vision

Range in duration from 60ms to 100ms

Saccades are the fastest type of eye movement, (max vel. of 500 degrees per second

We cannot pick up information during a saccade (saccadic suppression) - reason why all of our perceptions are different

Question 7

eye movement metrics

Answer 7

no. fixations

gaze/fixation duration

scan path

Question 8

no. of fixations

Answer 8

a concentration of a large number of fixations in a certain area may be related to a user’s interest in the object or detail presented in that area when viewing a scene.

Question 9

gaze/fixation duration

Answer 9

gaze is defined as a number of consecutive fixations in an area of interest.

Gaze duration is the total of fixation durations in a particular area

longer for experts

Question 10

scan path

Answer 10

the scan path is a line connecting consecutive fixations.

It can be revealing of a viewer’s visual exploration strategies and is often very different in experts and novices.

Question 11

PCE in sport: a meta-analysis

Answer 11

Mann et al (2007)

systematic diffs in visual search behavs also observed, with experts using fewer fixations of longer duration, including prolonged QE periods, compared with non-experts

Question 12

Mann et al (2007)

Answer 12

Expert-novice differences in Visual Search Strategy have been found in a range of sport settings including: racquet sports, baseball and volleyball

1. Experts are better than non-experts in picking up perceptual cues, as revealed by measures of response accuracy and response time.
2. Systematic differences in visual search behaviours; with experts using fewer fixations of longer duration, (including prolonged quiet eye periods), compared with non-experts.
3. Several factors (e.g., sport type, research paradigm employed, and stimulus presentation modality) significantly moderated the relationship between level of expertise and perceptual-cognitive skill.

Question 13

Mann et al (2007) - point 2

Answer 13

Experts (generally) have a lower search rate:
– Fewer and longer fixations
– Less scattered / More efficient

Expert athletes use their rich knowledge base to pick out the most salient aspects of the display.

In addition, lower search rates are associated with less saccadic suppression (and hence more time to process relevant information; Moran et al. 2002)

Question 14

search rate

Answer 14

number of fixations / mean duration of fixations

Question 15

visuo-motor control

Answer 15

Movements are guided by vision

Movements are more accurate when guided by accurate vision

Gaze tends to rest on a target before motor act is initiated and this visual information is used to guide action

The neural mechanisms regulating goal-directed movements profit from the accurate and timely spatial information of the foveated target

Question 16

visually guided actions

Answer 16

task-specific (goal-directed) eye movements
– support the planning and control of manual action
– are present throughout action sequences for more complex tasks
- form of attention in brain - paying attention to goals and goals directing movement

Top-down instructions dominate gaze behaviour in the performance of visually guided actions

“The challenge is now to find out how descending attentional mechanisms control gaze during purposeful action” (Land 2009, pp.61).

Question 17

the head tracks and gaze predicts: how the world’s best batters hit a ball

Answer 17

Mann et al.

track where will hit the bat

who are the experts they are using

Question 18

QE

Answer 18

Defined as the final fixation or tracking gaze directed to a single location or object in the visuomotor workspace within three degrees of visual angle for a minimum of 100 ms.

The quiet eye has an onset that occurs before the final (critical) movement in the motor task, and an offset that occurs when the fixation or tracking deviates off the target by more than three degrees of visual angle for more than 100 ms (Vickers, 2007).

Basically….the last fixation to a target before moving

longer duration the better

Question 19

QE - why useful?

Answer 19

It’s simple : your hands are controlled by your brain, which gets valuable information about what to do from your eyes.

As you perform a visually guided motor task, your brain needs to organize more than 100 billion neurons. These neural networks are informed by your gaze, and control your hands, arms and body as the stroke is performed (e.g., Land, 2009).

These networks will stay organized for only a short period of time; a window of opportunity opens that must be used when it is at its most optimal - brain has lots of other things to be doing

50% of brain taken up by visual cortex

info from eyes incredibly valuable when going to move

Question 20

the specifics of the QE

Answer 20

interested in timing and duration

how do we know QE imp?

Question 21

interested in timing and duration

Answer 21

1. How long do performers track / aim at a target?
2. When do they initiate this final fixation (QE onset)?
3. When do they stop this final fixation (QE offset)?

Question 22

how do we know QE imp?

Answer 22

1. Proficiency Differences
2. Effects of Anxiety
3. Training

Question 23

Empirical studies - types of tasks

Answer 23

whilst tasks require diff motor actions, perceptually they all ask subject to fixate on critical target area and to time acquisition of info so there is optimal coupling

Question 24

Experts golf putt

Answer 24

focus on just one dimple of ball

average 2-3s QE

QE reflects the optimisation of visual attention for the planning and control of movement parameters

Question 25

final fixation prior of initiation of back swing

Answer 25

Vickers argues that about 2s qQE periods optimal

3 key aspects of putt

1. look at ball prior to initiation of stroke
2. look at ball during stroke
3. maintain dwell on ‘ball location’ just after stroke

Question 26

control of goal-directed and stimulus-driven attention in the brain

Answer 26

want to use dorsal attention and less of ventral attention

Question 27

From Wilson et al (2015)

Answer 27

more interaction from dorsal and less from ventral - focused state - smoother motor control output - get more info

Question 28

pressure and QE

Answer 28

Increased anxiety disrupts effective attentional control (QE)… AND … subsequent performance

Question 29

QE and choking: online control breaks down at the point of perf failure

Answer 29

putted until missed

final shot - also breakdown of QE

dwell - crucial to keeping perf going

Question 30

QE and perf in sport: a meta-analysis .- Lebeau et al (2016)

Answer 30

look at effect sizes of diff QE studies

large effect size for diff between experts and novices

large effect size between QE period to perf