Aim: Effect of intensity on two eyes
Requirement : Two eyes, a dark transparent glass, an object to glance.
1)Sit in a lit room
2)Look at fan with only right eye
3) Look at fan with only left eye through dark glass.
4) Look from both eyes( keep dark glass in front of left eye)
Observation : Brighter in only right eye, darker in only left and medium brightness with both eyes.
Result: Intensity do add when are different. Or more correctly they rather average out.
In your actual experiment, the intensities in two eyes just averaged out, that was mathematicaly equal to single eye.
1) Brightness is transferred via frequency principle. Greater the intensity of light, greater the frequency of AP transmitted.
2) [Action Potential ]
Action Potential has a fixed depolarising potential.
3) Each spatial point, in space, of vision, is represented on a single spatial point in occipital cortex.
Two action potential caused by same image pixel reach their representative point on occipital cortex area 17.
They are then sent to visual associative Area 18 for matching.
“Fusion” of the Visual Images from
the Two Eyes
To make the visual perceptions more meaningful, the
visual images in the two eyes normally fuse with each
other on “corresponding points” of the two retinas.
The visual cortex plays an important role in fusion. It
was pointed out earlier in the chapter that corresponding points of the two retinas transmit visual signals to
different neuronal layers of the lateral geniculate
body, and these signals in turn are relayed to parallel
neurons in the visual cortex
Source: Guyton and Hall, chapter 51.
Same impulses from same spatial point are sent to same interneuron.
The action potential cannot rise further.(Principle 1 above)
This fused signal reaches next neuron for further processing. Intensity is judged.
Same amplitude as of one eye reached, so same intensity was percieved by even two eyes.
If fused signal is of intermediate frequency, intermediate brightness is observed.