PSYCH101 Study Guide - Midterm Guide: Hexaco Model Of Personality Structure, Unconscious Mind, Color Vision
7 May 2018
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PSYCH 101
In Introduction to Psychological Science
Week 4 Readings: October 2nd
Module 4.1 – Sensory and Perception at a Glance
- Sensation and perception are different yet integrated processes
- The Necker Cube: staring at the object for several seconds causes it to eventually switch perspectives
Sensing the World Around Us
- Two stage process for detecting then translating the complexity of the world into meaningful experiences
- Step 1 sensation: the process of detecting external events by sense organs and turning those stimuli into
neural signals
➢ Raw sensory information is relayed to the brain (transduction), where perception occurs
- Step 2 perception: involves attending to, organizing, and interpreting stimuli that we sense
➢ Ex. Recognize sounds, understand colours + shapes + motions together make up an image of a human
being walking towards you
- Transduction: when specialized receptors transform the physical energy of the outside world into neural
impulses
➢ The neural impulses that travel into the brain ultimately give rise to our internal representation of the
world
➢ The sensory receptors involved in transduction are different for different senses (ex. sound cochlea)
- Action potential: mechanism for transmitting information in the brain
- Each brain area is responsible for processing separate different sensory signals
➢ Vision occipital lobe
➢ Auditory temporal lobes
- Johannes Muller (German physiologist) first proposed the idea that different senses were separated in the
brain ~ doctrine of specific nerve energies
➢ Researchers at McMaster demonstrated that infants have a number of overlapping sensations
➢ As children age, the pathways in their brains become more distinct
➢ THEREFORE, perception is a skill that our brains learn through experience
- The sensory receptors and brain areas related to perception are extremely sensitive to change
➢ Our brains evolved to be highly selective to signals or danger
- Orienting response: describes how we quickly shift our attention to stimuli that signal a change in our
sensory world
➢ Unchanging stimuli elicit less activity thus less attention is directed to things that stay constant overtime
- Sensory adaptation: the reduction of activity in sensory receptors with repeated exposure to a stimulus;
allows us to adjust to surroundings
- Changing camera angles in television prevent sensory adaptation, makes it difficult for you to look away
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Stimulus Thresholds
- William Gustav Fechner coined psychophysics: the field of study that explores how physical energy such as
light and sound and their intensity relate to psychological experience
➢ Psychophysicists measured the minimum amount of a stimulus needed for detection & the degree to
which a stimulus must change in strength
- Absolute threshold: the minimum amount of energy or quantity of a stimulus required for it to be reliably
detected at least 50% of the time that it is presented
➢ Animals (e.g., cats and dogs) have lower absolute thresholds for detecting things like light and sound
- Difference threshold: the smallest difference between stimuli that can be reliably detected at least 50% of
the time
➢ The more intense the initial stimulus, the larger the amount of it that must be added for the differences
threshold to be reached
- Compared to people, dogs have amazingly low absolute thresholds for detecting smells
Signal Detection
- How do we confirm whether these stimuli were truly perceived, or whether the individuals were just
guessing
- Signal detection theory: states that whether a stimulus is perceived depends on both sensory experience and
judgement made by the subject; must examine a sensory process and a decision process
➢ Sensory process: experimenter presents a faint stimulus or no stimulus at all
➢ Decision process: subject must report whether or not a stimulus was actually presented
➢ False alarm: when you think you recognized a stimulus but nothing was present
➢ A miss: when you fail to detect a stiulus’s pesee
- Though aalzig ho ofte a peso’s esposes fall ito eah of these fou ategoies, pshologists a
accurately measure the sensitivity of a peso’s sensory system
- Factors affecting if a person can detect a weak stimulus:
➢ Sensitiit of that peso’s seso ogas
➢ Cognitive and emotional factors (expectations, psychological and autonomic nervous system arousal
level, motivation)
Subliminal Messaging
- We can perceive subliminal stimuli under strict lab conditions; subliminal effects occur and can produce small
effects in the nervous system
- Tape stud: thei epetatios led the to eliee that the had ipoed a ailit ee though the had’t
received any subliminal help for that ability
- Research suggests that subliminal essages ae ulikel to eate otiatios that had’t previously existed;
messages may just enhance goals or motivations
- Cannot create a new motivational state, therefore it is not a form of mind control
- Subliminal messaging can activate an already existing motivational state
Gestalt Principles of Perception
- Gestalt psychology emphasizes that the whole is greater than the sum of its parts
➢ Ex. the individual parts of an image me have little meaning on their own, but in succession, takes on a
significant perceived form
- Figure-ground principle: objects or figures in our environment tend to stand out against a background
(applies to hearing as well)
➢ Exactly which object is the figure and the ground depends on several factors including what you are
motivated to pay attention to
- Proximity: a dozen of eggs in a carton looks like 2 rows of 6
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- Similarity: e.g., grouping people together that wear a uniform
- Continuity: lines and objects tend to be continuous, rather than abruptly changing direction’
- Closure: tendency to fill in gaps to complete a whole object
- Gestalts principles must be put together to demonstrate an incredibly important characteristic of the
perceptual system we create our own organized perceptions out of different sensory inputs
Working the Scientific Literacy Model
- Until 1980 few people believed that backward messages in music
could be perceived when the music was played forward
➢ Changed with the Judas Priest law suit
- Top-down processing: when our perceptions are influenced by our
expectations or by our prior knowledge
- Bottom-up processing: occurs when we perceive individual bits of
sensory information (e.g., sound) and use them to construct a more
complex perception (e.g., message)
- Top-down processing can influence the perception of the image
- The way we perceive the world is a combination of both top-down
and bottom up processing
- Perceptual set: a filter that influences what aspects of a scene we perceive or pay attention to
- Sometimes are perceptual sets are so fixed that we fail to notice unexpected objects that are clearly visible
Attention and Perception
- Divided attention: paying attention to more than one stimuli or task at the same time
- Selective attention: involves focusing on one particular event or task (ex. focused studying, driving)
- Inattentional blindness: a failure to notice clearly visible events or objects because attention is directed
elsewhere
➢ Shows that when we focus on a limited number of
features, we might not pay attention to anything
else
Module 4.2 – The Visual System
- Vision and the cognition that goes with it is something
that we fine-tune with experience
How the Eye Gathers Light
- Retina photoreceptors ganglion cells optic
nerve
- Senses, translates into neural impulses, transfers it to
the brain for complex perceptual processing
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PSYCH101 Full Course Notes
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Document Summary
Module 4. 1 sensory and perception at a glance. Sensation and perception are different yet integrated processes. The necker cube: staring at the object for several seconds causes it to eventually switch perspectives. Two stage process for detecting then translating the complexity of the world into meaningful experiences. Step 1 sensation: the process of detecting external events by sense organs and turning those stimuli into neural signals. Raw sensory information is relayed to the brain (transduction), where perception occurs. Step 2 perception: involves attending to, organizing, and interpreting stimuli that we sense. Recognize sounds, understand colours + shapes + motions together make up an image of a human being walking towards you. Transduction: when specialized receptors transform the physical energy of the outside world into neural impulses. The neural impulses that travel into the brain ultimately give rise to our internal representation of the world. The sensory receptors involved in transduction are different for different senses (ex. sound cochlea)
