Sensation and Perception

1. Sensation and Perception Sensation: your window to the world Perception: interpreting what comes in your window.

2. Sensation • Sensation - The passive process of receiving and detecting a stimulus by the nervous system. • Process of sensing our environment through taste, sight, sound, touch and smell • Example: Hearing Mrs. Joseph speak, the sound waves travel to the ears. The hair on the cells in the cochlea help transmit the information to the brain

3. Perception • 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 • Based on our prior experiences and expectations • Example: • Seeing letters on a page and interpreting them as our favorite passage in a novel

8. Bottoms-up Processing • 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: • seeing the individual fruits in this picture • Hearing a voice speak about AP Psych

9. Top Down Processing • 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 • Examples: • Seeing the face in the picture made up of fruit • I _ope yo_ get an 5 on t_ _ A _e_am • Negative expectations about the pain of childbirth can increase pain during the birthing process

10. Find the following hidden items: • Scissors • Banana • Screwdriver • Horn • Heart • fish • boat • Shoe • needle

11. Aoccdrnig to a rscheearch at an Elingsh uinervtisy, it deosn’t mttaer in what oredr the ltteers in a word are, th olny iprmoetnt tihng is that frist and lsat ltteer is at the rghit pclae. The rset can be a toatl mses and youcan still raed it wouthit a porbelm. This is bcuseae we do not raed erveylteter by it slef but the word as a wlohe.

12. Selective Attention • Selective Attention - Ability to focus our conscious awareness on a particular stimulus • Example: Cell phone usage while driving a car

13. Selective AttentionExample

14. The Stoop Effect • Stroop Effect - Demonstrates the nature of automatic processing versus conscious visual control. The difficulty you had reading it was due to semantic interference

15. Cocktail-party phenomenon • cocktail party effect - 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: • You are at the football game and are cheering for the Comets when you hear Ms. Short call your name

16. Selective Inattention • Change Blindness/Inattentional Blindness - Falling to notice changes in the environment • Example: Eating your lunch in the cafeteria, when your friend switches your sandwich and you don’t notice • Choice Blindness - failure to notice a switch in a choice that is made • Example: Participants asked to pick between two photographed faces, when photographs are switched… • Change deafness – failure to notice a change in voices that are speaking • Example: Listening to Mrs. Joseph speak, failure to notice that Mrs. Harvey is now speaking

17. Create your own examplesPick two that you are having the most difficulty with and make your partner come up with a new example • Sensation • Perception • Bottoms-up processing • Tops-down processing • Selective Attention • Stroop Effect • Cocktail Party effect • Inattentional Blindness • Choice Blindness • Change Deafness No stinky examples!

18. Pop Out Effect • Pop out – stimuli we don’t chose to attend to but they draw our eyes and demand our attention • Example: Picture on the left

19. Complete sensation in the absence of complete perception is best illustrated by • Weber’s Law • Prosopagnosia • Conduction deafness • Color constancy • Sensory interaction

20. The process by which we select, organize, and interpret sensory information in order to recognize meaningful objects and events is called • Sensory adaptation • Parallel processing • Sensation • Perception • accomodation

21. Patients' negative expectations about the outcome of a surgical procedure can increase their postoperative experience of pain. This best illustrates the importance of • Transduction • Accomodation • Sensory adaptation • Difference thresholds • Top down processing

22. Researchers found that 40% of people focused on repeating a list of challenging words, failed to notice a change in the person speaking. This illustrates • Top Down Processing • Bottoms up Processing • The Difference Threshold • Change Deafness • Perception

23. You typically fail to consciously perceive that your own nose is in you line of vision. This illustrates • Subliminal perception • Change blindness • Perception • Selective Attention • The cocktail party effect

24. Psychophysics • Psychophysics - Study of howphysical stimuli are translated into psychological experience. • Psychologists use thresholds to measure these events • Example: Tracking a person’s eye movements jumping every .33 of a second

25. Thresholds • Threshold – the point at which a sensory information is strong enough to be noticed • Absolute threshold – The smallest amount of a sensory stimulus needed to notice that the stimulus is there at all • Examples:

26. Signal Detection Theory • 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…people respond differently to same stimuli • Example: Enemy submarine, • Waiting for the Pizza man to come at a busy party

27. Subliminal Stimulation • Subliminal– below one’s absolute threshold for conscious awareness • Example: • Listening to tapes in your to get you to lose weight • Priming– increased sensitivity to certain stimuli due to prior experience outside conscious awareness • Example: Seeing a picture of a mouse before viewing the picture on the left

28. 100 75 Percentage of correct detections 50 Subliminal stimuli 25 0 Low Medium Absolute threshold Intensity of stimulus Do Subliminal Messages work? • Based on studies, some people do respond to stimuli below the absolute threshold, under some circumstances. • People behave differently at different threshold levels • Priming can briefly influence preferences or perceptions • Complex behaviors are NOT influenced by subliminal messages • Some people are more suggestible than others • Placebo effect

29. Subliminal messaging vs. Priming • Why the difference between priming studies and subliminal message studies? • priming: immediate, short-term effect on simple judgments and actions • subliminal messages: aim for long-term effects on consumer purchases, voter sentiment, or even suicide – most studies not proven to provide long term effects

30. Difference Threshold Difference Threshold (AKA 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: • Some people are better at detecting slight variations in the taste of pop

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44. Weber’s Law • 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

45. Weber’s Law • JND • Pitch = .003 ( if someone sings a little off key, we will be able to tell) • Loudness = .10 • Saltiness = .20 • Light = .08 • Example: • JND for a 10oz weight = 1 oz. To notice a 50 oz weight would be 5oz • JND for a 10 decibel sound = .10 decibels . To notice a sound of 30 decibels would be _______?

46. Sensory Adaptation • Sensory Adaption - Diminished sensitivity as a consequence of constant stimulation • Example: Jumping into a cold swimming pool, doesn’t feel cold after a while Your eyes when you turn off the lights Do you feel your underwear all day?

47. After listening to the television for 10 minutes, you fail to notice how loud the volume is. This is an example of • Weber’s Law • Habituation • Sensory adaptation • Just noticeable difference • Absolute threshold

48. Which theory emphasizes that personal expectations and motivations influence the level of absolute thresholds? • Signal detection theory • Just noticeable difference • Weber’s law • Bottoms-up theory • Tops-down theory

49. The minimum amount of stimulation a person needs to detect a stimulus 50 percent of the time is called the • Adaptation threshold • Difference threshold • Absolute threshold • Subliminal threshold • Change threshold

50. A subliminal message is one that is presented • while an individual is under hypnosis. • below one's absolute threshold for awareness. • in a manner that is unconsciously persuasive. • with very soft background music. • Repetitiously