slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
PSY 2012 General Psychology Chapter 5: Sensation and Perception PowerPoint Presentation
Download Presentation
PSY 2012 General Psychology Chapter 5: Sensation and Perception

Loading in 2 Seconds...

play fullscreen
1 / 31

PSY 2012 General Psychology Chapter 5: Sensation and Perception - PowerPoint PPT Presentation


  • 379 Views
  • Uploaded on

PSY 2012 General Psychology Chapter 5: Sensation and Perception. Samuel R. Mathews, Ph.D. Associate Professor The Department of Psychology The University of West Florida. Sensation. Environmental Stimuli. Stimuli must exceed the threshold necessary

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'PSY 2012 General Psychology Chapter 5: Sensation and Perception' - orsen


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
psy 2012 general psychology chapter 5 sensation and perception

PSY 2012 General PsychologyChapter 5: Sensation and Perception

Samuel R. Mathews, Ph.D.

Associate Professor

The Department of Psychology

The University of West Florida

slide3

Sensation

Environmental

Stimuli

Stimuli must exceed the threshold necessary

to trigger the sense receptors in the sense organs

Sensory Organs

Sense organs change the physical

stimuli into electrochemical energy

that travels across the neural pathways

in a process termed transduction

Brain

The brain converts the neural impulses to the

experiences we report of sight, sound, touch,

smell, taste, etc.

key concepts in sensation
Key Concepts in Sensation
  • Transduction: the process of converting physical energy (e.g., light, sound waves, pressure) to electrochemical energy in the cells of the sense organs
  • Sensory Adaptation: the process of our sense organs becoming habituated to levels of stimulation in our environment (e.g. losing sensitivity to the experience)
key concepts in sensation5
Key Concepts in Sensation
  • Thresholds: Sensitivity of the sense organ
    • Absolute threshold: lowest level of physical energy a sense organ can detect
    • Difference threshold: the minimal difference between two levels of a given stimulus for which a difference can be detected.
did you see that or signal detection theory
Did you see that?OrSignal Detection Theory
  • Sense organs’ abilities to detect the presence or change in a stimulus is based on:
    • Signal strength and quality
    • Background noise
    • Expectations or mental set
    • Prior experience with the stimulus
    • Fitness/health of the organ itself
slide8

Visual Sensation

Light Energy

Light energy varies in wave length (within the electromechanical

spectrum) which produces color and intensity or amplitude

which produces brightness

Eyes

Transduction occurs in the retina

of the eye in specialized cells (rod &

cone cells) that detect color and intensity

Parietal and

Occipital Lobes

The optic nerve via the bipolar cells and ganglion cells

transmits the signals from the retina to the brain. These signals

feed primarily to the parietal lobe and visual cortex of the

occipital lobe.

color sensation
Color Sensation
  • Cone cells, concentrated in the fovea of the eye are sensitive to color but require relatively high levels of light to “fire”
  • Initial process of color sensation is the stimulation of 3 types of cone cells (each type senses either red, blue, or green) in the retina of the eye—the trichromatic process
  • The second phase of color sensation is in the bipolar cells and operates within the opponent-process theory
    • Cone cells transmit nerve signal to the bipolar cells
    • Opposing colors cancel each other out (red and green are opponent colors and yellow and blue are opponent colors)
    • The results of this process are transmitted to the brain via the optic nerve.
seeing in the dark or the perception of brightness
Seeing in the darkorThe Perception of Brightness
  • Rod cells
    • Sensitive to lower levels of light;
    • Located around the periphery of the fovea;
    • Responsible for so-called night vision
      • Note: Night vision can be enhanced by looking slightly away from the object in darker situations. Rod cells are more densely concentrated outside the fovea of the eye.
slide13

Auditory Sensation

Sound Waves

Sound waves vary in frequency (Hz or CPS) that relates to pitch

and amplitude (peak-to-peak within a cycle) that relates to volume

Ears

Transduction occurs in the ear as the

sound waves impact the tympanic membrane

which sets up vibrations impacting bones

(hammer, anvil, & stirrup) which pass vibrations

to the cochlea stimulating the basilar membrane which

converts the energy to neural signals

Temporal

Lobe

The auditory nerve transmits the signals from the inner ear

to the brain. These signals feed primarily to the auditory cortex

of the temporal lobe

qualities of sensation of sound
Qualities of Sensation of Sound
  • Pitch:
    • Based on the frequency of the sound waves;
    • 20Hz to 20,000Hz is the normal range for humans with healthy hearing sense
    • Location on basilar membrane that receives the greatest stimulation represents one system of picking up pitch above 1000Hz (place theory);
    • Basilar membrane neurons rate of firing based on frequency is related to sounds below 5000Hz (frequency theory).
    • Between 1000Hz and 5000Hz is the range of typical human speech—hence redundancy.
qualities of sensation of sound15
Qualities of Sensation of Sound
  • Loudness
    • Based on amplitude of the sound waves

A

M

P

L

I

T

U

D

E

1 Cycle

Frequency=number of cycles/second

qualities of sensation of sound16
Qualities of Sensation of Sound
  • Timbre:
    • Characteristic sound of a particular event (e.g. dog barking, door slamming, heavy metal guitar rip)
      • Attack and decay: the onset and duration of a sound coupled with the intensity and rise or fall of the sound volume
      • Vibrato: periodic change in pitch of the tone
      • Harmonic content: the complexity of the tone combinations
other major senses
Other Major Senses
  • Motion and position in space:
    • Vestibular sensation based on cilia (tiny hairs) in the inner ear;
      • As our head moves, fluid in the semicircular canals stimulate the cilia and stimulate nerve cells that give us the sensation of motion
      • Conflicts between vestibular sensation and other motion cues coming from vision can bring about motion sickness
      • Inner ear infections can lead to similar experiences
    • Kinesthetic sensation based on feedback from muscles
      • Allow us to position our extremities in space
      • With vestibular sense we are aware of our spatial position
    • Vestibular and Kinesthetic sensations are processed in the parietal lobe and lead to awareness of our spatial position
making sense of our senses perception
Making Sense of our Senses:Perception
  • Once the sensation is detected (signal detection theory) the mind begins to “make sense” of the sensory experience. This involves:
    • Interpreting (naming, recognizing)
    • Organizing (creating structures based on existing mental structures or creating new structures)
    • Perceptual experiences typically involve higher cognitive functions and rely on top-down and bottom-up processes
perception
Perception
  • Bottom-up Processes:
    • These processes are “driven” by the sensory experiences created from the stimulus from the environment;
    • Distinctive features of the stimulus control our representation of that stimulus (e.g. color, motion, texture)
  • Top-down Processes:
    • Processes driven by the individual’s biases, expectations, motives, and existing knowledge
    • Features of the stimulus can be interpreted in a number of ways depending on the state of the organism
    • The organism “constructs” unique precepts from the sensory experiences
    • Frequently the perceptual experience is at odds with the “reality” of the stimulus
perception20
Perception
  • Perceptual constancy:
    • Stability of members of a category of objects or events;
    • Based on shared attributes
    • Identification of objects/events is constant even with highly different sensory experiences
    • Top-down driven based on experience and expectations about the objects or experiences
      • Shape constancy
      • Color constancy
      • Etc.,
perception21
Perception
  • Bridging the top-down and bottom-up process:
    • Sense organs are “wired” to detect particular features of the environmental stimuli
    • Once detected, the sensory experience and the expectations, motives, and mental set of the organism bring to the experience a set of plausible interpretations.
      • Therefore, perception is a hybrid of top-down and bottom-up processes.
perceptual theories
Perceptual Theories
  • Gestalt Theory:
    • Human beings evidence a tendency to aggregate elements of a stimulus array into an organized pattern or array;
    • This pattern or array is the basis from which we interpret sensory information into perceptions.
    • Such interpretations are always based on incomplete sensory information and reflect individual experience
slide26

Perceptual Grouping

X O X O X O X

X O X O X O X

X O X O X O X

X O X O X O X

X O X O X O X

Law of Similarity

slide27

Perceptual Grouping

X O X O X O X

X O X O X O X

X O X O X O X

X O X O X O X

X O X O X O X

Law of Proximity

depth perception
Depth Perception
  • Binocular Cues (both eyes)
    • Binocular Convergence: degree to which the two eyes must converge to focus on the object
    • Retinal Disparity: difference in perspective of the two images on the retina
depth perception29
Depth Perception
  • Monocular Cues (single eye depth perception)
    • Relative Size: for objects known to be similar in size, the one seen to be larger is perceived to be closer
    • Interposition: if one object hides part of another, the one hiding the other is perceived to be closer
    • Relative Motion: objects at different depths from the eye appear to move at different rates when the individual is in motion (closer objects appear to “move” more quickly)
perceptual set seeing what we expect
Perceptual Set: Seeing what we expect
  • Expectations can influence what we are “ready” to perceive
  • Contextual “set-ups” can prepare us to one interpretation vs. another
  • Perception is NOT reality; it is OUR reality