Cognitive Factors -

Overview:

  • Factors affect the ability to execute a movement, in response to a stimulus and when a stimulus isn’t relevant to the movement.

  • Cognitive factors include: decision-making, attention, motivation, emotional aspects, memory, the ability to switch between tasks - These can effect Task, and related to the Environment

  • Underlying assumptions = Movement is more difficult when cognitive demands of the tasks are higher.

  • Reaction time is often used to study how cognitive factors influence movement

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  • Factors that affect the ability to respond to a stimulus:

    • Individual: readiness (anticipation), attention, arousal/anxiety, motivation

    • Stimulus factors: Modality of presentation (visual, auditory, tactile), Intensity (loudness, brightness), Complexity (amount of information), Predictability

    • Number of choices

    • Stimulus-response compatibility

    • Required accuracy of response

    • Time between response (psychological refractory period - PRP)

    • Task Practice

Anticipation:

Prepared for what and when a signal cueing one to move occurs

  • Experimenters design tasks so participants can’t anticipate the stimulus (to control other factors)

  • In real-life people commonly anticipate situation in daily life e.g when walking and we see a different terrain in front we might step differently.

    • Research Example - How a person deals with a slippery surface.

      Walked along steel rollers, that the researchers could lock or unlock. In some trials participants were told whether the surface was slippery or not. In others they were told nothing.

    • The flat foot strategy was used when participants knew the surface was slippery. Also reduced horizontal impulse and rate of loading - foot lands on surface with less force and you shift weight onto that foot slower

  • Effector Anticipation:

    • Have to estimate the duration of the motor planning and execution of your own movement, then factor this interval into the decision of when to initiate the movement at the appropriate time.

    • E.g Baseball Batter - when to swing the bat

    • This concept relates to all interceptive actions. A person must know how long it takes to plan and make their move.

  • Temporal Anticipation

    “The ability to anticipate when a stimulus will occur. “

    • It depends on:

      • Foreperiod regularity - Foreperiod = interval between warning cue & stimulus onset

      • Regular results in reaction time - as one can predict the duration and thus knows when the stimulus will appear.

    • Foreperiod Duration

      • Too short of duration leads to increased reaction time - possibly to not enough time to prepare

      • Too long of duration (aging foreperiod) - leads to increased reaction time when ‘catch’ trials intermixed (Catch trial = normal stimulus is withheld)

      • Leads to shorter reaction time when no ‘catch’ trials present - Longer the duration, the more probable the stimulus will occur

Attention

“The information processing capacity of an individual” - has a fixed capacity

also defined as “The preparedness for and selection of certain aspects of our physical environment..” - because of selection, certain processes are prevented from occurring

  • Pre-Cue paradigm to study effects of attention

    • Shows how attention can influence reaction time

    • Each trial participant fixates on centre of screen and receives 1 of 3 cues, task is to lift finger from key as fast as possible after stimulus onset.

    • You can move you “spotlight attention” based on the arrows and if the pre-cue is valid, your are faster

Multitasking and Movement

You must often deal with a variety of competing demands. Performing multiple tasks simultaneously can impact performance on one or all of the tasks

  • Dual-task paradigm:

    • Studies the effect of multitasking

    • logic (or assumption):

      • Information processing capacity is limited for any individual

      • Performing a task requires a given portion of that individuals capacity

      • So if two tasks are performed simultaneously and require more than the total capacity, then performance diminishes

    • Paradigm has a primary and secondary task

      • Primary: Usually the motor behaviour (walking, reaching, standing) - depends on the experimental question

      • Types of secondary tasks:

        1. Continuous: performed throughout the primary task

        2. Discrete: a stimulus to which the participant must respond is presented at various times throughout primary task.

    • If 2 tasks compete for the same attentional resources, there will be decrement in performance on one or both tasks

      • This is “capacity interference” is a measure of attention - measured as a decline in performance due to limited central capacity, if structural interference can be ruled out.

      • ‘Watch out’ for Structural Inference, which is decreased performance caused by physical structures

        • Usually a confound to avoid in experimental design

        • Example Standing balance as primary and vocalization as a secondary - counting changes breathing which impacts postural sway.

Multitasking and Cognitive decline:

Aging and disease can place a large strain on the ability to multitask, increasing the likelihood of performance decrements.

Associations with walking and dual tasking:

  • Reduced gait speed in older adults with & without neurological impairment

    • “Stops walking while talking” is associated with fall risk

  • Increased gair variability during dual tasking predicts future and multiple falls

  • People visually sample environment differently - Evident in parkinson’s patients, and in people with glaucoma as well as healthy older adults.

Arousal and Anxiety

Arousal = an internal state of alertness or excitement

Anxiety = the emotional and cognitive impact of arousal, such as nervousness or tension

  • Arousal, anxiety, and performance:

    • Inverted-U relation - optimal performance requires moderate arousal levels, low and high levels lead to decline in performance

    • Zone of optimal functioning

      • Zone defining a range of arousal levels for optimal performance

      • Depends on individual and task

    • Research shows complex skills may require lower arousal levels. Implications: athletes should perform a task-specific warm-up to ensure arousal is optimal.

    • How a person interprets their own arousal level will dictate the effect of arousal on performance.

  • Perceived threat and walking

    • Threatening situation result in slower gait speed:

      • More cautious gait strategy e.g reaching with the foot to find the next ground level when walking

    • Gaze fixation strategies altered

      • You may focus on a narrow region of space or you might look in all directions

  • Perceived threat and postural sway

    • Test participant while standing on an elevated platform

    • Stiffening strategy observed

      • Postural sway decreases with fear

Central Processing - The 3 stages of information processing

Can be serial and/or parallel. Traditional view = processed serially, Modern view = response selection and programming can be processed mostly in parallel. Reaction time is used as a measure to assess central processing

  • Stimulus Identification Stage:

    • Stimulus must be identified or recognised as part of a pattern.

    • Once the stimulus or pattern is detected, it must be transformed into AP that are sent to the brain for further processing

  • Response Selection Stage:

    • The decision of whether to respond and which response to select

    • Factors influencing response selection, and hence reaction time include:

      1. # of choices

      2. S-R compatibility

    # of choices:

    • selection of response require greater amounts of time with increased choices because of the associated increase in information processing

    • Choice reaction time (RT) paradigm is used to test this concept

    • Hicks Law: relationship between choice RT and # of S-R alternatives

      • Shows with more alternatives there is increased reaction time = more central processing

      • Some exceptions to this, which result to shorter choice reaction time - Familiarity with the task, Having a predictable task.

      Hicks Law Equation - ?????

    Stimulus-response compatibility:

    • Speed of response depends on the relationship between patterns of stimulus and response - similar patterns lead to faster reaction time

    • Important for human factors an ergonomics

    • Simon effect: a psychological phenomenon where participants respond faster and more accurately to a stimulus when the stimulus and response locations correspond, even when the stimulus location is irrelevant to the task

  • Response Programming Stage:

    • Occurs after response selection

    • Individual must translate the plan into a program that consists of details regarding the appropriate muscle activity to make the movement.

    • Requires the brain:

      1. Retrieve a motor program from memory

      2. Prepare the program for activation

      3. Initiate the movement to achieve a goal

    Henry Rogers experiment demonstrates factors that influence reaction time at this stage:

    • S-R alternatives are all the same for each task, so processing speed in the stimulus identification and response selection stages should be the same.

      • Movement is only variable that differed

    • Increased RT as the complexity of the movement is increased - suggests that extra time is needed to program the action

    • In this example - the increase in the # of movements parts is the primary reason for the increased RT - But accuracy demands and movement duration can also contribute to increased RT.

Psychological Refractory Period (PRP) -

  • Delay period during which you cant select a 2nd movement until a 1st movement is initiated - Results in delay in response to the second of 2 closely spaced stimuli.

  • Double-stimulation paradigm used to show this concept

    • Two stimuli (S1, S2) presented and require different responses (R1, R2), they are separated by an interval (Stimulus Onset Asynchrony - SOA)

    • Processing S1 (to produce R1) causes interference with processing S2

    • Exception: Grouping effect - very short SOA = 2 stimuli dealt with as a single more complex event, don’t see a greater RT2

    Factors that influence PRP:

    • Effects of Practice - Increase practice decreases RT2

    • Complexity of 1st stimulus (e.g # of S-R Choices) - Less complex = shorter RT2

    • Stimulus-Response Compatibility - Compatible stimuli = shorter RT2

    Implications of PRP (“Fake” in Sports)

    • Through practice, you can learn what the PRP value is for a player/ sport and exploit it.

Memory and Movement: Memory can influence movement.

  • Spatial Working memory

    • Temporary storage of spatial information

    • Application: we can’t/don’t always maintain constant gaze on an object we interact with, so we might still remember its position or other characteristics

  • Long-term memory

    • Section 8

DO NOT USE MUSCLE MEMORY* Correct term = Motor Memory.