SENSATION AND PERCEPTION

Sensation—the process of detecting a physical stimulus

Perception—the process of integrating, organizing and interpreting sensations

Five Sensations:vision gustationaudition toucholfaction

Is there a sixth??

Anatomical substrate for vision, i.e., the pathway from the stimulus in the environment to the occipital lobe, where we “see”

Vision begins with a stimulus from the environment—the range of the electromagnetic field from radio waves to cosmic rays; only a small portion is visible to humans

The pathway begins with-light from the environment which then passes through the-cornea, pupil and lens-light is focused on the retina

It is here that “transduction” occurs*TRANSDUCTION* is the point at which the

stimulus from the environment (light) becomes a nerve impulse (electrochemical neurotransmission)

The photoreceptors in the lining of the retina are called rods and cones-axons of rods and cones form optic nerve-optic nerve crosses at the optic chiasm-nerves project to the lateral geniculate nucleus of the thalamus to the-visual cortex in the occipital lobe

WHERE WE SEE!

Hearing begins in the environment and ends in the auditory cortex in the temporal lobe

PATHWAYThe stimulus from the environment is sound, in

the form of waves.The sound is “funnelled” by the outer ear—

pinna, ear canal and eardrum.

Middle ear—three tiny bones, called ossicles– anvil, stirrup, hammer

Inner ear—cochleasnail-shaped structure about the size of a pealined with hair cells that bend, causing “transduction”

*TRANSDUCTION* is when a stimulus from the environment (sound) becomes a neural impulse (electrochemical neurotransmission)

Transduction occurs at basilar membranesAxon neurons become the optic nerveOptic nerve projects to the medial geniculate

nucleus of the thalamusThalamus to auditory cortex inTemporal lobe, where we “hear”.

If a tree falls in the forest, and there’s no one there to hear it, does it make a sound?

OTHER SENSATIONS• Smell

• Taste

• Touch

Also—kinesthesia (body movement)and vestibular (balance)

PERCEPTION

• refers to the process of integrating, organizing and interpreting sensory information into meaningful representations

GESTALT LAWS OFFORM PERCEPTION

• Figure-ground

• The Law of Similarity

• Law of Closure

• Law of Good Continuation

• Law of Proximity

• Law of Simplicity

Depth Perception

ILLUSIONS(MISPERCEPTIONS)

Muller-Lyer

• Moon Illusion

Shepherd Table’s Illusion