SENSATION AND PERCEPTION

Sensation—the process of detecting a physical stimulus Perception—the process of integrating, organizing and interpreting sensations Five Sensations: visiongustation auditiontouch olfaction Is there a sixth??

nsns 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 PATHWAY The 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—cochlea snail-shaped structure about the size of a pea lined 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 membranes Axon neurons become the optic nerve Optic nerve projects to the medial geniculate nucleus of the thalamus Thalamus to auditory cortex in Temporal 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 OF FORM 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