Visual proprioceptive

control of standing in human infants

David N. Lee & Eric Aronson

By: Vannida Lorn

Background

Three important receptor systems:

1. Exteroception – stimuli outside

the body

2. Proprioception – position of the

body

3. Interception – stimuli inside the

body

Traditional View of StandingStanding requires constant

muscle adjustmentsIdeal position is verticalMovement away from vertical

causes lost of balanceStanding involves proprioception

because you use mechanoreceptors

However…Physical influence on standing,

but what about visual influence?Vision not only exteroceptive, but

also proprioceptive? Supporting Evidence:

◦Wood’s (1895) “haunted swing”◦Edward (1946) and Witkin &

Wapner’s (1950) blindfold experiment

Hypothesis

Is visual proprioceptive information used in maintaining balance in standing?

Subjects:

Human infants

Baby Vannida!

Apparatus3 walls and a ceiling, suspended

with 4 ropes

Apparatus (cont.)Inside of the

“room” was illuminated

Pictures were hung to make it more cozy

ProcedureSwayed the room forward (which

should cause a backward sway in the infant)

Swayed the room backward (which should cause a forward sway in the infant)

ConflictVisual proprioception calls for

compensatory movement opposite of room movement

BUT mechanical proprioception should counteract the compensatory sway

…so if there is any abnormal loss of balance, this suggests that visual information dominated over mechanical information

Movement of room forward causing a feeling of a backward sway

Results82% of responses resulted in a

loss of balance◦26% sway◦23% stagger◦33% fall

Suggests Vision > Mechanics

Alternative Hypotheses

1. Avoidance response to a looming effect

◦However, this only applies when the room swayed towards the infant

2. Flow of air from the swaying of the room caused the loss of balance

◦Flow of air was so slight, unlikely to have been the cause of loss of balance

ConclusionFor infants: visual proprioception >

mechanical proprioception in maintaining posture

Visual system matures quicker than the motor system

During early life, visual proprioception is used to learn how to stand

As we get older, with practice does our mechanical proprioception performs as efficient as vision.