Sensation & Perception

Presentation on theme: "Sensation & Perception"— Presentation transcript:

1 Sensation & Perception

2 The Lion King

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4 Do you see the message hidden?

5 Do you see the message hidden?

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7 Political Subliminal Message
What impact does this message have? Will it last? Commercial

8 Subliminal Messages Hidden messages targeted at our subconscious mind.
Examples: 1. Small images inside a larger picture 2. An audio message hidden inside a recording 3. Messages in song played backward 4. Hidden words or pictures that quickly appear 5. Powerful marketing tools Effects us on a emotional level Short lived results

9 Sensation & Perception
Sensation- stimulation of the sense organs Raw data of experience: smells, sights, sounds, pain, etc. Perception- creating meaning from the raw sensory information

10 Basic Process Sensory organs absorb energy from a physical stimulus in the environment Sensory receptor cells detect stimulus energies and convert them into neural impulses (transduction) Electrochemical message is sent to the brain Specific areas of the brain organizes the input and transforms them into something meaningful

11 Attention Selective 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

12 Psychophysics- how physical stimuli are translated into psychological experience
Gustav Fechner’s work on thresholds Threshold- is a dividing point between energy levels that do and do not have a detectable effect Absolute 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:

13 JND- just noticeable difference is the smallest difference in the amount of stimulation that a specific sense can detect The absolute threshold is the jnd from nothing (no stimulus) JND is greater for stronger stimuli than for weaker ones As a stimulus increases in magnitude, the JND becomes larger

14 Weber’s Law- states that the size of a jnd is a constant proportion of the size of the initial stimulus This portion is called the Weber Fraction It 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!

15 Fechner’s Law The 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.

16 Imagine you are monitoring a radar screen

17 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: Hits-Detecting signals when present Misses-Failing to detect signals when present False Alarms-detecting signals when they are absent Correct Rejection-Not detecting signals when they are absent

18 Setting Criterion Depends 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.

19 Sensory Adaptation Gradual decline in sensitivity to prolonged stimulation Ex: Garbage In reality, the stimulus intensity (the odor) stays the same but with continued exposure your sensitivity to it decreases Ex: Jumping into a swimming pool It allows people to ignore the obvious but you can notice CHANGES in sensory input A behavioral adaptation that has been sculpted by natural selection