Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Measuring Sensation and Perception
 Must first focus conscious awareness or
attention
 Sense organs detect information via sensation
 Stimuli are converted to signals that the brain
can process
 Information is interpreted through process of
perception
 Psychophysics – branch of psychology
devoted to study of sensation and perception
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Absolute Thresholds
 What are the limits of senses?
 Absolute threshold
 Minimum intensity of stimulus that can be detected
50% of the time
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
The Just Noticeable Difference
and Weber’s Law
 What is the minimum change in intensity of a
stimulus that can be detected?
 Difference threshold or just noticeable difference
(JND)
 Weber’s Law – change in stimulus needed to
produce a jnd depends on intensity of stimulus
when first present
 Helps explain subjectivity of experience
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Processing Without Awareness:
Subliminal Stimulation of the Senses
 Subliminal – stimuli at intensities too weak to
reach absolute threshold
 The Coke “experiment”
 Flashed “drink coke” throughout movie (faster than
conscious awareness)
 Testing subliminal perception
 Failure to yield convincing evidence of
effectiveness of subliminal persuasion
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Extrasensory Perception: Can Perception Occur
Without the Five Senses?
 Extrasensory Perception (ESP)
 Ability to acquire information about the world without
using the known senses
 Ganzfeld procedure
 “sender” and “receiver” in different rooms
 Little support for ESP
 Neuroimaging
 no difference in activity when correct vs incorrect
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
How Vision Works: Light Waves and Energy
 Vision depends on the eye converting
electromagnetic waves into action potentials for
brain to process
 Light is electromagnetic energy
 Color and brightness determined by physical
characteristics of light energy
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Measuring Light: Wavelength and Amplitude
 Wavelength
 Distance between peaks of consecutive waves
 Amplitude
 Height of each wave peak
 Human eye perceives only part of the field of
electromagnetic energy
 Visible spectrum of light is 360 to 750 nm
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Properties of Light:
Hue, Brightness and Saturation
 Hue corresponds to light’s wavelength
 Shorter is cool, longer is warm
 Brightness corresponds to light’s amplitude
 Higher is brighter
 Saturation corresponds to light’s purity
 Light of single wavelength produces most saturated
(i.e. richest)
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
The Anatomy of the Outer Eye
 Cornea
 Clear outer surface protects eye and begins
focusing process
 Passing through, light waves slow down and bend
 Pupil
 Opening through which light passes
 Iris (colored part) controls adaptation of pupil to
light and dark
 Lens
 Focuses images through accommodation
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
The Retina:
Light Energy to Neural Messages
 Surface lining inside of back of eyeball
 Once light waves focus, conversion of light
waves into neural impulses happens at the retina
 Rods and cones convert light into action
potentials
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Optic Nerve and Blindspot
 Blindspot - point where optic nerve leaves retina;
no rods or cones
 The blindspot is not a problem because
 At side of visual field
 Both eyes work together
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Rod and Cones
 Rods
 Long and skinny, sensitive to all colors of light
 Don’t transmit color information to brain
 Highest concentration found at edges of retina
 Cones
 Short and fat, transmit color information to brain
 Require higher intensity light to activate
 Highest concentration found at fovea
 More rods than cones
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Turing Light Energy into Neural Messages
 Photopigments – chemicals activated by light
energy found in rods and cones
 Dark and Light Adaptation
 Accomplished partly by changes in pupil size
 Additional process involves photopigment use
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
How We See Color
 Three different types of photopigments in
cones help us see color
=
 Primary colors of light are red, green, and
blue; all colors made from combinations
 Different from primary colors of paint (red, yellow,
and blue)
 Perception of color is due to the color of light
entering eye
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
The Opponent-Process Theory
of Color Vision
 Opponent-process cell sensitive to two colors
of light
 Red/green, yellow/blue, black/white
 Cells can only detect presence of one color at a
time, therefore oppose each other
 Explains negative afterimages
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Do Men and Women See the World Differently?
 Females
 Better at discriminating objects, naming colors,
processing facial expressions
 Prefer using many colors
 Prefer warm colors
 Males
 Better at processing moving objects and spatial
aspects of object
 Evolutionary or cultural?
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Vibration and Sound
 Sounds produce waves of compressed air
that convert to neural impulses
 Cycle = the peak of the sound wave and the
valley following it
 Loudness = amplitude (height of wave)
 Measured in decibels (dB)
 Pitch = frequency (number of cycles/second)
 Measured in hertz (Hz)
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
A Noisy Environment Can Lead to Hearing Loss
 Exposure to noisy environments associated
with greater age-related hearing loss
 Limit exposure to loud noises (e.g. loud
concerts)
 Pay attention to difference in hearing after
exposure to loud noises
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
The Anatomy and Function of the Ear
 Cochlea – turns sounds waves into neural
impulses
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Taste: Information From the Tongue
 Taste and smell are interconnected
 Referred to as chemical senses as chemicals
must come into contact with sense organs
 Gustation (taste) - chemicals dissolved in
saliva come into contact with tongue
 Smell - Chemicals in air come into contact
with cells in nasal cavity
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Properties of Taste:
The Four - or Five - Tastes
 Four types of taste that tongue detects
 Bitter, sweet, salty, sour
 A fifth taste
 Umami (glutamate) primarily found in
Asian foods
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Anatomy and Function of the Tongue
 Taste buds – reside in pits between papillae
(bumps on tongue)
 Convert chemicals into neural impulses that are
conveyed to brain
 2000 to 5000 taste buds
 Can regenerate after damage
 Different taste buds are found in different
locations along tongue, none in center
 Taste blindspot
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Why Don’t We All Like the Same Foods?
 Age
 Loss of taste buds with age; may diminish sense of
taste
 Culture
 Availability of food sources; religious values and
traditions
 Learning
 Biological Factors
 Hormonal and genetic influences
Supertasters and nontasters
 Sense of smell

Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
The Mystery of Smell
 Researchers do not know exactly how sense
of smell works
 Lock-and-key-theory: Specific odor molecules
unlock certain olfactory receptors
 Converted impulses travel from olfactory
nerve to olfactory bulb in brain
 Some information to smell cortex, some to limbic
system; emotional associations
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pheromones – Are Some Odors Sexy?
 Used by animals to communicate via pheromones
Humans?
 Some evidence affects humans:

 Women cycle together (exposed women’s sweat)
 More interactions with men (men’s sweat)
 No perfumes found to increase our attractiveness
to others
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Touch: The Skin Sense
 Originates in skin, which contains touch
receptors
 Different types of receptors for touch, temperature,
and pain
 Pressure on skin leads to neural impulses that
travel to spinal cord and brain
 Signals enter thalamus and go to somatosensory
cortex of parietal lobe
 Threatening stimuli go to limbic system
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
The Body Senses: Experiencing the Physical
Body in Space
 Senses that help us experience the body in
space
 Kinesthesis
 Sensing position of body parts in space and in
relation to one another
 Vestibular
 Sense of balance
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Kinesthesis
 Important in athletics
 Uses information from muscles, tendons, skin
and joints
 Processed in somatosensory cortex and
cerebellum
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Perception: Interpreting Sensory Information
 Perception – interpretation of sensory
information
 Top-down perceptual processing
 VS.
 Bottom-up perceptual processing
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
© 2010
Using What We Know:
Top-Down Perceptual Processing
 Using previously gained knowledge to help
interpret stimulus
 Helps in quickly perceiving something
 Helps fill in missing information
 Can lead to mistakes in perception
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Building a Perception From Scratch: BottomUp Perceptual Processing
 Using properties of stimulus to build
perception of the stimulus
 Piecing together perception of many different
components
 Both processes are used continually
 Perception further influenced by complexity of
environment, including movement
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Understanding What We Sense: Perceiving
Size, Shape, and Brightness
 Perceptual constancy - how our brain
“corrects” perception to allow a constant
perception of objects
 Size constancy, brightness constancy and
color constancy
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Depth Perception: Binocular Cues
 3-dimensional world is projected onto retina in
two dimensions – how corrected?
 Binocular depth cues rely on information
based on retinal disparity
 Each eye sees slightly different information
 Amount of disparity experienced is a function of
distance from object
 Brain uses amount of retinal disparity to
calculate how far object is, enabling depth
perception
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Depth Perception: Monocular Cues
 Rely on the use of one eye
 Easily demonstrated in art
 Interposition
 Height on horizon
 Relative Size
 Texture Gradient
 Aerial Perspective
 Linear Perspective
 Motion parallax
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Perceiving Form: The Gestalt Approach
 The whole of a perception is greater than the
sum of its parts
 Perceptual laws
 Figure-ground
 Figures are seen in the context of background;
figure pulled forward and ground pushed back
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Perceiving Form: The Gestalt Approach
(cont.)
 Closure
 Tendency to mentally fill in or close object
 Preference for solid shapes over lines
 Proximity and similarity
 Group stimuli together that are close in proximity or
similar
 Good continuation
 Prefer to perceive stimuli that are part of a pattern
 Camouflage
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Perceiving Form: Feature Detection Theory
 Cells in visual cortex fire in response to only
certain stimuli
 Confirmed by animal studies
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Errors Due to Top-Down Processing: Seeing
What We Expect to See
 Misapplied expectations
 Thinking we heard or saw something not
actually heard or seen
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Errors Due to Perceptual Constancy
 Moon illusion - Moon appears larger as it rises
over horizon
 No interposition cues when moon overhead
 Ponzo illusion - Lines of equal length lying
across converging lines appear to be unequal
in length
 Attempt to maintain size constancy
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning
Pastorino/Doyle-Portillo
Essentials of What Is Psychology? 1st edition
© 2010 Cengage Learning