Locomotion and the environment Flashcards
Reactive adaptation
costly
responds to mechanical perturbations (tip and slip)
Proactive adaptation
response to visual stimuli
reduced environment-induced costs
metabolic cost (optimising locomotion cost)
mechanical costs
Optic flow
self motion
move forward and world moves backwards
Pattern impact on optic flow
slow drivers down as pattern makes then feel like they are moving too fast
when stripes get narrower walk speed reduces
Locomotion and vision
initiate avoidance strategies, proactive adjustments
critical time points that use visual input
route planning, obstacle avoidance, changes in terrain and low level sensory impact
Locomotion research: vision
10% of time look down at ground in familiar environments
40% if obstacles
only during guiding foot placement
Walking without vision
pretty accurate but not as accurate as with vision
Gaze control study outlined
measure eye movement and where are in step cycle. Flat, medium and rough terrain
see where and when fixate and when feet come down
Gaze control study results
about 1 and a half meters looking compared to where they are
hardly any difference in step length
step duration longer for medium and rough
look ahead distance - flat 2.5m m+r 1.5m
look ahead time- fixed 1.5s before get to that point irrespective of speed and terrain
target and walking study
discrimination task
head movement indication of gait cycle
timing of target - modulating task performance
most problems when head highest (1 foot up 1 foot down)
evolved to tune to environment
optimised for sensory info for environment niches
signal to noise ratio
Stripe frequency (spatial frequency)
most sensitive to 3 cycles per degree
tuned as certain things in nature show as dangerous e.g. snake pattern
signal lost if noise of stripes too loud
Lower signal to noise ratio
higher uncertainty about state of environment
higher risk
higher attentional demands (increased cognitive load)
more sampling time required to reduce locomotor costs.
cognitive load and visual discomfort affect git dynamics
Walking and 3cpd
walk slower and spatial frequency as you come closer to 3 cycles per degree
predicting environment for action (natural environment)
visual predictions being used confirmed by proprioceptive feedback (sensory info derived from different sensory systems is congruent/matched)
Predicting an environment for action (urban environments)
visual predictions can diverge substantially from proprioceptive feedback ( sensory info derived from different sensory systems may be incongruent)
perceived illusionary depth affecting gait
Primrose and café wall effect
café wall leads to veering, dizziness and falling
nice to look at but not interact with
Urban regeneration and inadvertent negative side effects
real world impact illusions causing people to fall
high predication error leading to increased fall risk
Physical activity
few people walk sufficiently to profit from health benefits
to improve perform the four steps
Health benefits for interacting with nature
pollution decreases physical and mental wellbeing
exposure to nature helps restore mental fatigue, cognitive resources and decrease stress
Attention restoration theory
performance increases in nature environments as no distractions and can mind wander
city not restorative distraction, attentional demands and cognitive fatigue
Characteristics of restorative environments
softly fascinating
evoke feeling of separation from fatiguing situations
sense of extent of being part of something different
compatible with desires and goals
Testing attention restoration theory
base line test first
phase where fatigue then test then restore then test
restorative environments lead to increased working memory, flexible control and attentional control
Stress recovery theory
few environments stressors nature
non-nature sensory noise and pollution and social stressors
