sensation & perception

19

Upload: ulla-berry

Post on 31-Dec-2015

37 views

Category:

Documents


0 download

DESCRIPTION

Sensation & Perception. The Lion King. Do you see the message hidden?. Do you see the message hidden?. Political Subliminal Message. What impact does this message have? Will it last? Commercial. Subliminal Messages. Hidden messages targeted at our subconscious mind. Examples: - PowerPoint PPT Presentation

TRANSCRIPT

The Lion King

Do you see the message hidden?

Do you see the message hidden?

Political Subliminal MessageWhat impact does this message have?Will it last?Commercial

Subliminal MessagesHidden messages targeted at our subconscious

mind.Examples: 1. Small images inside a larger picture2. An audio message hidden inside a recording3. Messages in song played backward4. Hidden words or pictures that quickly appear5. Powerful marketing toolsEffects us on a emotional levelShort lived results

Sensation & PerceptionSensation- stimulation

of the sense organs

Raw data of experience: smells, sights, sounds, pain, etc.

Perception- creating meaning from the raw sensory information

Basic Process1. Sensory organs absorb energy from a physical

stimulus in the environment2. Sensory receptor cells detect stimulus energies

and convert them into neural impulses (transduction)

3. Electrochemical message is sent to the brain4. Specific areas of the brain organizes the input

and transforms them into something meaningful

AttentionSelective

Attention- focusing our awareness on a particular stimuli

Cocktail Party Phenomenon- filter out many sounds to maintain one conversation but will notice your name in another conversation

Psychophysics- how physical stimuli are translated into psychological experience

Gustav Fechner’s work on thresholdsThreshold- is a dividing point between energy

levels that do and do not have a detectable effectAbsolute Threshold- minimum amount of

stimulation that an organism can detect 50% of the time Environment can affect detection of a stimulus Examples of absolute threshold under ideal conditions Online demo:

http://www.garyfisk.com/anim/threshold.swf

JND- just noticeable difference is the smallest difference in the amount of stimulation that a specific sense can detectThe absolute threshold is the jnd from

nothing (no stimulus)JND is greater for stronger stimuli than for

weaker onesAs a stimulus increases in magnitude, the

JND becomes larger

Weber’s Law- states that the size of a jnd is a constant proportion of the size of the initial stimulusThis portion is called the Weber FractionIt can apply to all the senses but different

fractions apply to different types of sensory input

Ex: Weber fraction for weights is 1/30, which means you should detect the difference btw a 30 ounce weight and a 31 ounce weight

Envelope/Book EXPERIMENT!

Fechner’s LawThe magnitude of a sensory experience is

proportional to the # of JNDs that the stimulus causing the experience is above the absolute threshold.

Constant increments in stimulus intensity produce smaller and smaller increases in perceived magnitude of sensation.

EX: Dark room with lamp and three bulbs.Three equal increases in stimulus intensity

produce progressively smaller differences in the magnitude of sensation.

Imagine you are monitoring a radar screen

Signal Detection Theory The detection of stimuli involves decision

processes as well as sensory processes, which are influenced by many factors besides stimulus intensity

Radar Screen with four possible outcomes:A. Hits-Detecting signals when presentB. Misses-Failing to detect signals when presentC. False Alarms-detecting signals when they are

absentD. Correct Rejection-Not detecting signals when

they are absent

Setting CriterionDepends on our

expectations and on the consequences of missing a signal or of reporting a false alarm.

Ex: Waiting for the pizza guy at a party.

Sensory AdaptationGradual decline in sensitivity to

prolonged stimulationEx: GarbageIn reality, the stimulus intensity

(the odor) stays the same but with continued exposure your sensitivity to it decreases

Ex: Jumping into a swimming poolIt allows people to ignore the

obvious but you can notice CHANGES in sensory input

A behavioral adaptation that has been sculpted by natural selection