1 / 38

Chapter 2

Chapter 2 . Perceptual Processes I: Visual and Auditory Recognition. Background on Visual Object Recognition. object recognition pattern recognition. Background on Visual Object Recognition. The Visual System distal stimulus proximal stimulus Retina Functional stimulus sensory memory

jane
Download Presentation

Chapter 2

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 2 Perceptual Processes I: Visual and Auditory Recognition

  2. Background on Visual Object Recognition • object recognition • pattern recognition

  3. Background on Visual Object Recognition • The Visual System • distal stimulus • proximal stimulus • Retina • Functional stimulus • sensory memory • iconic memory, visual sensory memory • primary visual cortex

  4. Background on Visual Object Recognition • Organization in Visual Perception • Gestalt Psychology • figure • ground • ambiguous figure-ground relationship • Explanation for Figure-Ground Reversal • adaptation of neurons in visual cortex • people try to solve the visual paradox

  5. Background on Visual Object Recognition • Organization in Visual Perception • Illusory Contours (subjective contours) • Human perception is more than the sum of the information in the distal stimulus.

  6. Background on Visual Object Recognition • Theories of Visual Object Recognition • templates • Feature-Analysis Theory • distinctive feature • compare new letter to stored list of distinctive features

  7. Background on Visual Object Recognition • Theories of Visual Object Recognition • Feature-Analysis Theory • Eleanor Gibson's research • time required to decide if two letters are different • recognizing letters and numbers on envelopes

  8. Background on Visual Object Recognition • Theories of Visual Object Recognition • Feature-Analysis Theory • Hubel and Wiesel's research • measure response of single neuron to simple visual stimulus • retinal region and orientation • feature detectors

  9. Background on Visual Object Recognition • Theories of Visual Object Recognition • Feature-Analysis Theory • Problems with feature-analysis approach • complex shapes in nature • relationship between features • distortion of features with movement

  10. Top-Down Processing and Visual Object Recognition • The Distinction Between Bottom-Up Processing and Top-Down Processing • bottom-up processing—emphasizes stimulus characteristics • top-down processing—emphasizes concepts, expectations, memory

  11. Top-Down Processing and Visual Object Recognition • The Distinction Between Bottom-Up Processing and Top-Down Processing • Top-down processing is strong when a stimulus is registered for just a fraction of a second. • Top-down processing is alsostrong when stimuli are incomplete or ambiguous. • Object recognition combines bottom-up and top-down processing.

  12. Top-Down Processing and Visual Object Recognition • Top-Down Processing and Reading • Context helps us recognize letters of the alphabet during reading. • We don't read letter-by-letter. • Analyzing all the individual features in the letters of words would be too much work for the perceptual processes.

  13. Top-Down Processing and Visual Object Recognition • Top-Down Processing and Reading • We can still manage to read a sentence, even if some of the middle letters in a word have been rearranged. • word superiority effect

  14. Top-Down Processing and Visual Object Recognition • Top-Down Processing and Reading • The context of a sentence facilitates the recognition of a word in a sentence. • Rueckl and Oden's bears/beans experiment • Both bottom-up and top-down processing operate in a coordinated fashion.

  15. Insert Figure 2.6 here

  16. Top-Down Processing and Visual Object Recognition • In Depth: Overactive Top-Down Processing and "Smart Mistakes" in Object Recognition • Change Blindness • fail to detect a change in an object or a scene • Simons and Levin's stranger-and-the-door study

  17. Top-Down Processing and Visual Object Recognition • In Depth: Overactive Top-Down Processing (continued) • Change Blindness • Detecting the difference between two scenes • Top-down processing encourages us to assume that the basic meaning of the scene will remain stable. • important changes identified more quickly • do not store a detailed representation of a scene

  18. Top-Down Processing and Visual Object Recognition • In Depth: Overactive Top-Down Processing (continued) • Inattentional Blindness • fail to notice when an unexpected but completely visible object suddenly appears • Simons and Chabris's basketball study • awareness test • monkeybusiness

  19. Top-Down Processing and Visual Object Recognition • In Depth: Overactive Top-Down Processing (continued) • Reconciling "Smart Mistakes" in Object Recognition • ecological validity • Perceptual representations change rapidly; the visual system does not track each detail.

  20. Top-Down Processing and Visual Object Recognition • In Depth: Overactive Top-Down Processing (continued) • Reconciling "Smart Mistakes" in Object Recognition • Thevisual system is fairly accurate in creating the "gist" or general interpretation of a scene. • focus on what is important

  21. Top-Down Processing and Visual Object Recognition • In Depth: Overactive Top-Down Processing (continued) • Reconciling "Smart Mistakes" in Object Recognition • Theme 2: Our cognitive errors can often be traced to the use of a rational strategy

  22. Face Perception • should be a challenging task • need to recognize faces from different angles, in different settings, with different expressions

  23. Face Perception • Recognizing Faces Versus Recognizing Other Objects • face perception as "special" • Tanaka and Farah—facial features in context vs. isolation • feature identification vs. holistic approach • gestalt

  24. Face Perception • Neuroscience Research on Face Recognition • prosopagnosia • inferotemporal cortex • face recognition cells in monkeys • fMRI studies • brain's response to faces in upright and upside-down positions • face-inversion effect Thatcher illusion

  25. Face Perception • Applied Research on Face Recognition • cashiers' judgments about ID photos • security surveillance systems • video clips of professors • later recognize from photos • familiarity and expertise

  26. Speech Perception • Speech perception requires the auditory system to: • record sound vibrations of someone talking • translate vibrations into a sequence of sounds that you perceive to be speech • distinguish the sound pattern of one word from all other irrelevant words • separate voice of speaker from background noise, including other conversations

  27. Speech Perception • Characteristics of Speech Perception • phoneme • Four Characteristics of Speech Perception • Listeners can impose boundaries between words, even when these words are not separated by silence. • Phoneme pronunciation varies tremendously.

  28. Speech Perception • Characteristics of Speech Perception • Four Characteristics of Speech Perception • Context allows listeners to fill in some missing sounds. • Visual cues from the speaker’s mouth help us interpret ambiguous sounds.

  29. Speech Perception • Characteristics of Speech Perception • Word Boundaries • The actual acoustical stimulus of spoken language rarely shows clear-cut pauses to mark the boundaries between words. • Listeners use knowledge about language in order to determine the boundaries between words.

  30. Speech Perception • Characteristics of Speech Perception • Variability in Phoneme Pronunciation • Phoneme pronunciation varies tremendously. • pitch, tone, and rate • lack of precision, sloppy pronunciation • coarticulation

  31. Speech Perception • Characteristics of Speech Perception • Context and Speech Perception • Top-down factors influence speech perception. • We use our knowledge of language to help us perceive ambiguous words. • Phonemic restoration • Warren & Warren's wheel/heel/peel study • Role of top-down processing

  32. Speech Perception • Characteristics of Speech Perception • Visual Cues as an Aid to Speech Perception • Visual cues from the speaker’s mouth help us interpret ambiguous sounds. • McGurk effect McGurk effect • compromise between discrepant sources of information • superior temporal sulcus

  33. Speech Perception • Theories of Speech Perception • The Special Mechanism Approach • Humans are born with a specialized device that allows us to decode speech stimuli. • Speech sounds are processed more quickly and accurately than other auditory stimuli. • phonetic module/speech module • categorical perception

  34. Speech Perception • Theories of Speech Perception • The General Mechanism Approach • Humans use the same neural mechanisms to process both speech sounds and nonspeech sounds. • event-related potentials (ERPs) research • phoneme judgment and visual cues

  35. http://www.zedocumentaries.com/brainstorythree

More Related