Sensation and Perception

Our Sensational Senses

LO 6.1.A Distinguish between the basic processes of sensation and perception, explain how the doctrine of specific nerve energies applies to perception, and discuss how synesthesia contributes to our understanding of sensory modalities.

LO 6.1.B Differentiate between absolute thresholds, difference thresholds, and signal detection.

LO 6.1.C Discuss why the principle of sensory adaptation helps us understand how the human perceptual system works.

LO 6.1.D Describe how selective attention and inattentional blindness are related.

The Riddle of Separate Sensations (1 of 5)

Sensation is the detection of physical energy emitted or reflected by physical objects.

The cells that do the detecting are located in the sense organs:

eyes

ears

tongue

nose

skin

internal body tissues

The Riddle of Separate Sensations (2 of 5)

Perception is the process by which sensory impulses are organized and interpreted.

Sensation begins with the sense receptors, cells located in the sense organs.

Receptors for smell, pressure, pain, and temperature are extensions (dendrites) of sensory neurons.

The receptors convert the energy of a stimulus into electrical impulses that travel along nerves to the brain.

The Riddle of Separate Sensations (3 of 5)

Separate sensations in the nervous system can be accounted for by:

anatomical codes (as set forth by the doctrine of specific nerve energies)

Müller

functional codes

The Riddle of Separate Sensations (4 of 5)

Sensory crossover from one modality to another can sometimes occur.

In synesthesia, sensation in one modality consistently evokes a sensation in another.

A person with synesthesia may say things like:

the color purple smells like a rose

the aroma of cinnamon feels like velvet

the sound of a note on a clarinet tastes like cherries

The neurological basis of synesthesia is uncertain.

The Riddle of Separate Sensations (5 of 5) Figure 6.1 The General Process of Sensation

Although the Individual senses respond to different kinds of energy in the world, the overall process of sensation is the same.

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Sensation and Perception