SENSATION AND PERCEPTION

Chapter 4

OBJECTIVE Distinguish between sensation and

perception Explain how they contribute to an

understanding of our environment

SENSATION AND PERCEPTION Sensation: Stimulation of sensory

receptors and the transmission of sensory information to the central nervous system. Sensory Organs: eyes, ears, nose etc. Automatic

Perception: Psychological process through which we interpret sensory stimulation. Reflects learning, expectations, and

attitudes

CONCEPTS FOR INTERPRETING STIMULATION Stimulation of the senses and the ways

in which people interpret that stimulation is affected by several concepts.

Absolute threshold Difference threshold Signal-detection theory Sensory adaptation

ABSOLUTE THRESHOLD Absolute Threshold: The weakest amount

of a stimulus that can be sensed. Dogs can hear whistles humans can’t.

Their absolute threshold is different from ours Absolute thresholds for humans have been

determined for the senses of vision, hearing, smell, taste, and touch

Difer from person to person More sensitive to certain sensory stimuli than

others If absolute thresholds differed much from what

they are, we might sense the world differently

ABSOLUTE THRESHOLDS

DIFFERENCE THRESHOLD Difference Threshold– minimum amount of

difference that can be detected between two stimuli. For example, let's say I asked you to put your hand

out and in it I placed a pile of sand. Then, I add tiny amounts of sand to your hand and ask you to tell me when you notice any change in the overall weight. As soon as you can detect any change in the weight, that difference between the weight of the sand before I added that last bit of sand and the amount of sand after I added it, is the difference threshold.

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SIGNAL-DETECTION THEORY Signal-Detection theory– a method of

distinguishing sensory stimuli that takes into account not only their strengths but also such elements as the setting, your physical state, your mood, and your attitude. Considers psychological factors

Motivation Expectations Learning Ex: Reading a book; can ignore distractions if

you are motivated to read.

SENSORY ADAPTATION Sensory Adaptation: the process by

which we become more sensitive to weak stimuli and less sensitive to unchanging stimuli Turn out the lights, can’t see, as your eyes

adjust to the dark you are able to see more clearly.

Live in the city, adapt to the noisy surroundings.