sensation and perception
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Sensation and Perception. Sensation: your window to the world Perception: interpreting what comes in your window. Sensation. the passive process of bringing information from the outside world to the body and the brain - PowerPoint PPT PresentationTRANSCRIPT
Sensation and Perception
Sensation: your window to the world Perception: interpreting what comes
in your window.
Sensation• the passive process of bringing information
from the outside world to the body and the brain
• Process of sensing our environment through taste, sight sound, touch and smell
• Example:
Perception• the active process of
selecting, organizing, and interpreting the information brought to the brain by the senses
• Perception is the way we interpret sensations and therefore make sense of everything around us
• Example:
Bottoms-up Processing• AKA - Feature analysis• Begins with the sensory
receptors and works its way up to the brain
• Use the features of the object itself to process the information
• Examples:
Top Down Processing• Processing information from
the senses with higher level mental processes using our experiences and expectations
• Using your background knowledge to fill in the gaps
• Example:
Cocktail-party phenomenon• The cocktail party effect
describes the ability to focus one's listening attention on a single talker among a mixture of conversations and background noises, ignoring other conversations.
• Form of selective attention.• Example:
Selective Inattention • Change Blindness/Inattentional Blindness -
Falling to notice changes in the environment• Example:
– Choice Blindness - failure to notice a switch in a choice that is made• Example:
– Change deafness – failure to notice a change in voices that are speaking• Example:
• Pop out – stimuli we don’t chose to attend to but they draw our eyes and demand our attention
• Example:
Psychometrics• Study of how
physical stimuli are translated into psychological experience.
• Psychologists use thresholds to measure these events
• Example:
Thresholds• Absolute threshold – minimum
stimulation needed to detect a stimulus of light, sound pressure, taste, or odor 50% of the time
• Examples:
Signal Detection Theory• Predicts how and when we
detect a signal amid background noise
• Assumes no absolute threshold
• Detection depends partly on a person’s experience, expectations , motivation and alertness… alertness…people respond differently to same stimuli
• Examples:
Subliminal Stimulation• Subliminal Stimulation –
below one’s absolute threshold for conscious awareness
• Example
• Priming – increased sensitivity to certain stimuli due to prior experience outside conscious awareness
• Example
Do Subliminal Messages work?
• Based on studies, some people do respond to stimuli below the absolute threshold, under some circumstances. – The problem is people
behave differently at different levels, so what could be subliminal (or below the threshold) for one person, may be supraliminal (above the threshold) for another person.
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25
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LowAbsolutethreshold
Medium
Intensity of stimulus
Percentageof correctdetections
Subliminal stimuli
Backmasking- More Subliminal Messaging?
Listing to Songs in Reverse
• There are legends about hidden messages in songs - Led Zeppelin's Stairway to Heaven was one of the first songs to have supposed hidden, satanic messages.
– http://jeffmilner.com/backmasking.htm
• Why does this seem to work?
Difference ThresholdAKA • Just Noticeable Difference – the amount
a change needed in a stimulus (stronger or weaker) for us to recognize the change has occurred
• the greater the intensity (ex., weight) of a stimulus, the greater the change needed to produce a noticeable change.
• Example:
Weber’s Law• Related to JND• For people to really
perceive a difference, the stimuli must differ by a constant "proportion" not a constant "amount".
• Proportion varies depending on the stimulus
• Example:
Weber’s Law• JND = Constant (K) X Intensity– Pitch = .003 ( if someone sings a little off key,
we will be able to tell)– Loudness = .10– Saltiness = .20– Light = .08
• Example: