What is reaction time?
the time from the onset of a stimulus to the response.
What is classed as a false start in an 100m sprint?
What are 2 methods of measuring reaction time?
when the reaction time is 0.1s or less. This is usually measured using a threshold(determined by SD on blocks when ready) and lights, then counting 20ms per frame.
* The 2 methods of measuring reaction time are: force plate measurements are taken in all directions. Whereas video method is only in the horizontal direction. The force plate has higher force points so is more accurate, but can also detect the movement of weight in preparation to the start.
Which test brings the fastest reaction time?
- The stimulus identification stage takes roughly 62.5ms longer (discrimination test/ simple RT)
○ shows that processing and identification stages take longer when there is a decision between 2 responses, but the same number of stimuli- one stimulus-response, the response selection stage takes longer. With the same number of stimuli, but different responses, any differences in reaction time are due to the specific stages compared.
- Choice reaction time test was faster due to the compatibility of the stimulus being on the same side as the response needed to be. (left side, left hand)
○ This used the ambient(spatial orientation)/dorsal stream(discrimination of objects) to make a compatible choice
○ Choice uses vison and concentration - In compatible-incompatible choice reaction time tests: choice reaction time compatible was SHORTEST, and choice reaction time incompatible & arms crossed was LONGEST
When is visual information most important
- After 400ms(between 400-600) the amount of catches made decreases by over 20%, as it becomes noticeably affected by the occlusion.
Visual information is mainly used in the last 400ms before catching, shown as occlusion between 400-800ms has the greatest decrease in number of successful catches- most important part of ball flight is the early stage, as only seeing the ball during the late stages gives the person very little time to process the information. Seeing the early stage allows for a prediction of the ball flight to be made(useful information)
Give an example in sport of a visual occlusion
- An example in sport is: the initial part of a pass must be seen to view its trajectory, so the player can get into the right position to catch the ball.
○ Whereas occlusions late e.g.: shoot at goalkeeper (occlusion of people)
○ Goalkeeper can use information on body language of shooter to predict where the ball will go
What are some considerations of the time to process visual information lab?
- Considerations are: a lab setting is not realistic to a real life situation. Different weather conditions and other experimental stimuli impact decision making. Also the experiment does not count for movement time of the response.
What is the effect of increasing the number of stimulus-response alternatives?
- When the number of stimulus-response alternatives doubled, the reaction time increased by approx. 210ms(gradient of line)
- Each additional stimulus increased reaction time by 100-200ms
What are some considerations of the Hick’s law lab?
- When 10 stimuli were reached you had to keep looking down at the keys.
○ Response time was not measured(reaction time + movement time) = so causes an increase- Penalty shot version of can game. There was no correlation of numbers.
Relied on spatial correlation inside the goal, needing greater thought and longer reaction time
- Penalty shot version of can game. There was no correlation of numbers.
What is the affect of changing the target size (W) or distance between targets(A)?
- When target size(W) is constant, but distance between targets(A) increases the average movement time increases linearly
- When amplitude(A) constant but target width(W) decreases the average movement time increases
- When the ratio between A and W remains constant, the average movement time increases slightly in a linear fashion.
What is the effect of close and open loop feedback on speed-accuracy trade-off?
○ When ratio increases, so does movement time (R squared = 0.995) therefore Fitts Law
○ Closed loop - increase distance and movement time allows enough time for feedback
○ Open loop - is between subsequent movements, but overall closed loop is used even if it takes longer feedback is still there
At what time is there still a chance of being successful?
Provide a sporting example
- There is a 50:50 chance of being successful at inhibiting the response around 175ms
- An example in sports: a penalty in football, the shooter can inhibit their movement by stuttering/jumping before kicking the ball. This doesn’t give the goalkeeper enough time to change the direction of their dive because it is too late in the response programming stage.
When can response time be positive/negative in the psychological refractory period?
- At 300ms the response time is almost the same as when the visual stimulus alone. This is because the first no longer effects the second stimuli.
○ Less than 300ms = NEG effect on response time
○ More than 300ms = NO difference in response time
What is a sporting example of the psychological refractory period?
- Sporting example: catching a pass in basketball(S1) and reacting to a defender(S2). Close time proximity doesn’t give enough time for the player to react. The longer-time period gives more reaction time to deceive the defender.
When did practise increase performance?
- Practise did increase the general performance, sharp rise at the start, but then plateaued
○ Between throws 30-50 there is an increase in consistency because it was a novice skill
○ Would improve the experiment if there was a graph showing all the throws
Why were the lab transfer test conditions not optimal?
What are some criticisms of this experiment?
- Transfer test conditions could have been more intense to make the situation more accurate. It is difficult to draw a conclusion from one transfer test, less accurate to determine if the skill can be transferred into a competitive environment
- Issue is that the low competitive environment caused the transfer trial to be another 6th trial block. So there is no motivation to do well
- Results of suggest that the improvements during practise are slightly permanent(retention)
○ The criticism is that there were not enough practise trials. The retention trial was within close proximity to the practise trial also.
○ Retention test is higher than the initial test
○ Transfer test was higher than retention test, 30mins caused the score in retention test to drop drastically
- Results of suggest that the improvements during practise are slightly permanent(retention)
What was expected from the feedback given compared to actual results?
- Difference between retention test and first trial block
○ No feedback = same in retention
○ Qualitative = expected differences (not in reality)
○ Quantitative = expected differences (also in reality)
○ Irrelevant = not expected differences (differences in reality)
What are some criticisms of the feedback in skill acquisition lab?
How could the experiment be improved?
- Criticism of conclusions drawn on the basis of this data:
○ Bean bags slid on floor as they landed, not accurately measuring where they landed
○ Retention test is in close proximity to the other trials, so doesn’t measure long-term retention
○ Human error
○ Measurement error - The experiment can be improved by;
○ Making sure the number of people in each group are equal
○ Average is taken from very little amount of people
What conditions had the greatest effect on balance?
- The condition with the most sway was the eyes closed and stood on the foam mat. This altered and moved most of the sensory pathways
- It was most difficult to balance in the eyes closed and head back condition
○ Vestibular feedback accounts for 20% whereas visual feedback is only 10% , so vestibular is more important in quiet standing on one leg
○ Visual was the eyes closed decreased standing time
○ Worst difference was between eyes closed and eyes open with head back(so vestibular is more important)
- It was most difficult to balance in the eyes closed and head back condition
What are some clinical ways that balance is measured?
- The ankle strategy mechanics control quiet standing
○ In clinical conditions this is tested by tensing calves or holding onto the ground with toes to keep balance
Provide a sporting example of balance
- Transition balance was found to be the most challenging overall
- When there were 2 conditions the increase in time taken, increased accuracy, because of the speed accuracy trade off theory
- An example in sport: gymnastics, netball (static and dynamic)
