Class 7 - Sensation and Perception Flashcards
Sensation
The ENCODING of physical energy from the environment
Perception
the DECODING of sensations (selection, organization, interpretation)
Psychophysics
The study of how physical stimuli are translated into a psychological experience
What are some of the different types of stimuli that we can detect?
Sound
Light
Weight
Proprioception aka Kinesthesis - known the location of your limbs
Visual Pathway
Optic Chiasma, role of rods and cones
Motor and Sensory Regions of the brain
Frontal lobe - motor cortex and motor association area (where voluntary movement is controlled)
Prefrontal Cortex - makes sense of what we experience
Broca’s area - produces speech
Auditory association area
Wernicke’s Area - processing and understanding written or spoken speech
visual cortex - process visual imagery
Parietal lobe - understand position of limbs (proprioception) and feel what is happening with the body - thalamus located here
Broca’s Aphasia
Non-fluent aphasia
Broken speech, cannot produce speech but still understand it
Broca’s Aphasia
Non-fluent aphasia
Broken speech, cannot produce speech but still understand it
Wernicke’s Aphasia
Fluent Aphasia
Cannot understand speech, but can still speak
Person says things that don’t make sense and cannot follow conversation
Agnosia
Inability to process sensory information
ex. face blindness
Visual Agnosia
Face blindness (Prosopagnosia) - cannot recognize people’s faces
Frontal Lobe
Planning, Concentration, Problem solving, Personality, Senses of Smell, Language Production (Broca’s area), Speech, Voluntary movement, Emotional Reactions
Parietal Lobe
Taste, Body Awareness, Touch and Pressure
Temporal Lobe
Hearing, Language comprehension (Wernicke’s area), Facial Recognition (face blindness indicates damage to temporal lobe)
Occipital Lobe
Visual Processing
Cerebellum
Movement, Coordination, Balance, Motor Memory (procedural memory)
Kinesthesis/Proprioception
Allows us to sense the position of our limbs in space as well as detect bodily movements
Mechanoreceptors
Detect mechanical disturbances like pressure or distortion
Proprioceptors
Respond to physical disturbances in the body
Muscle spindles detect…
Muscle stretch
Golgi Tendon Organs detect…
Tension in the tendons
Joint Capsule Receptors detect…
Pressure, tension, and movement in the joints
Thermoreceptors
Communicate information about heat
Nociceptors
Communicate information about pain
Left Brain Hemisphere Domain
Analytical, logical, detail oriented, ordered sequencing, rational thought, verbal, cautious, planning, math/science, right visual field, right side motor skills
Right Brain Hemisphere Domain
Emotional reasoning/processing, intuitive thought, holistic, random sequencing, emotional thought, non-verbal, adventurous, impulsive, creative (artists and musicians), imagination, left visual field, left side motor skills
Corpus callosum
connects 2 hemispheres of the brain for communication; severing this helps treat seizures
Weber’s Law
The size of the just noticeable difference is a constant proportion of the original stimulus value;
applies to more weak rather than strong stimuli
Just Noticeable Difference for Light Intensity
8% difference perceived in humans
Just Noticeable Difference for Sound Intensity
0.3% difference perceived by humans
Just Noticeable Difference for Weight
2% difference perceived by humans
Signal Detection Theory
A method for quantifying a person’s ability to detect a given stimulus (the “signal”) amidst other, non-important stimuli (“noise”)
Signal Detection Theory - Stimulus Present + Response Present
Hit
Signal Detection Theory - Stimulus Present + Response Absent
False Positive - Type I Error
Signal Detection Theory - Stimulus Absent + Response Present
Miss - False Negative - Type II Error
Signal Detection Theory - Stimulus Absent + Response Absent
Correct Rejection
Signal Detection Theory - Stimulus Absent + Response Absent
Type I Error
False Alarm - thinking something is there when it’s not
Type II Error
Miss - Missing something that is there
Detecting the stimulus requires
- Aquiring information
- applying criteria
2 types of Noise that can interfere with he subjects accuracy in detecting stimuli
- External noise - anything outside the subject (ex. strong cologne, air conditioner)
- Internal noise - anything within the subject (ex. thoughts, stomach growling)
Receiver Operating Characteristic (ROC) Curve
A ROC curve is a graphical plot that tracks the hit rate vs. false alarm rate in order to graphically represent a receiver’s (a person’s) accuracy at a given task
More area under the curve means more accuracy
Four Stimulus Properties that need to be communicated to the central nervous system
- Modality
- Location
- Intensity
- Duration
Modality of Stimulus
The type of stimulus that is being detected; modality is communicated based on the type of receptor that is firing
Location of Stimulus
Communicated by the receptive field of the stimulus
Intensity of Stimulus
How strong the stimulus is; encoded by the rate of firing of action potentials
Duration of Stimulus
How long the stimulus is present
Role of Tonic Receptors
Fire throughout the duration of the stimulus but are subject to more habituation;
generate action potentials as long as the stimulus is present
Role of Phasic Receptors
Detects changes or phases in and out;
Fire only when the stimulus begins; these receptors communicate changes in stimuli
Feature Detection Theory
There are certain neurons to detect certain visual stimuli like shape, angles, or motion; explains that certain parts of the brain are activated for specific visual stimuli;
The visual cortex passes sensory information to the part of the brain responsible for the perception of that object;
Explains why people who’ve had strokes have visual processing missing
Parallel Processing
Occurs so that many aspects of a visual stimulus (shape, color, motion, depth) are processed simultaneously rather than in a step-wise fashion (serial processing);
Also occurs at the level of detail to abstraction