FOOD STIMULI AND GENDER

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Figure 5: The Human Eye (Clker-Free-Vector-Images, 2016)

The photoreceptors located on the neural layer of the retina are specialized cells
called cones and rods. These two kinds of photoreceptors are responsible of the beginning
of the process of converting light into nerve impulses. Rods are accountable for shades of
gray and cones give rise to highly acute color vision. Cones are more concentrated in the
fovea centralis that is located in the middle of the macula lutea (also known as yellow spot)
and is the area of the highest sharpness of vision. To view an image it must be placed on the
fovea. This positioning of an image on the fovea leads to eye and head movements (Tortora
& Derrickson, 2010).
2.2.2 Eye movements
Three pairs of muscles are responsible for vertical, horizontal, and torsional eye
movements. The orientation of the eye decides the direction of the “look” (attention). This
orientation of the eyes is decided by the brain, which directs muscles toward relevant
locations. Most common types of eye movements are the following (Holmqvist et al., 2011).