Chapter 1: Intro to Perception Flashcards
perception
involves the higher brain functions that interpret events and objects
sensation
detecting simple elementary processes of a stimulus
The perceptual process
is made up of 7 steps, plus knowledge inside a person’s brain
3 major components of the perceptual process
Stimulus (steps 1&2)
Physiology (steps 3&4)
Behaviour (steps 5-7)
distal stimulus
the stimulus that the person is observing in the distance
proximal stimulus
representation of the stimulus on the receptors. In other words, the stimulus is “in proximity” to the receptors
principle of transformation
stimuli and responses created by stimuli are transformed, or changed between the distal stimulus and receptor
principle of representation
everything a person perceives is based on representations of stimuli that are formed on the receptors and the resulting activity of the person’s nervous system
sensory receptors
specialized receptors that respond to environmental energy with each sensory system’s receptors specialiZed to respond to a specific type of energy
transduction
the transformation of environmental energy to electrical energy
neural processing
the changes in signals that occur as they are transmitted through a network of interconnected neurons
primary receiving area
receives the electrical signals created through transduction
cerebral cortex
a 2 mm thick layer that contains the machinery for creating perceptions
occipital lobe
contains the primary receiving area for vision
temporal lobe
contains the primary receiving area for hearing
parietal lobe
contains the primary receiving area for touch, temperature, and pain
frontal lobe
receives signals from all of the senses and plays an important role in perceptions that involve the coordination of information between 2 or more senses
recognition
placing an object in a category and giving it meaning
visual form agnosia
an inability to recognize objects
action
involves motor activities in response ot the stimulus
knowledge
any information that the perceiver brings to a situation
rat-man demonstration takeaway
shows how recently acquired knowledge can influence perception
Bottom-up processing
processing that is based on the stimuli reaching the receptors
Top-down processing
processing based on knowledge
oblique effect
people see vertical or horizontal lines better than lines oriented obliquely (any orientation other than vertical or horizontal)
3 relationships of the perceptual process
Stimulus-behaviour, stimulus-physiology, physiology-behaviour
Relationship A
stimulus- behaviour/perception relationship: relates stimuli to behavioural responses
psychophysics
measures the relationship between the physical and the psychological
Relationship B
stimulus-physiology relationship: relates stimuli and physiological responses
Relationship C
physiology-behaviour/perception relationship: relates physiological responses and behavioural responses
absolute threshold
the smallest stimulus level that can just be detected
threshold
measure the limits of sensory systems
The classic psychophysical methods
3 methods developed by Fechner for measuring the threshold: the method of limits, constant stimuli, and adjustment
the method of limits
the experimenter presents a stimuli in either ascending or descending order and the threshold is determined by calculating the average of all the crossover points
the method of constant stimuli
different stimulus intensities are presented in a random order and the threshold is defined as the intensity that results in detection on 50% of trials
the method of adjustment
the participant adjusts the stimulus intensity continuously until they can barely detect the stimulus and the threshold is determined by asking about the average setting
most accurate classic psychophysical method
method of constant stimuli
difference threshold
the smallest difference between two stimuli that enables us to tell them apart
magnetic estimation
the experimenter presents a standard stimulus. The participant then hears sounds of different intensities and is asked to number them in a way that is proportional to the loudness of the original sound. Thus, the participant gives a number for loudness which is the perceived magnitude of the stimulus
recognition testing
measuring the process of categorization through a variety of different perceptual experiements
reaction time
the time between the presentation of a stimulus and a person’s reaction to it
phenomenological report
describing the things around you
physical tasks and judgements
research involving perception and subsequent action
why is it important to distinguish b/n physical and perceptual stimuli
because there is not a one-to-one relationship between the physical intensity of a stimulus and our perceptual response to it
electromagnetic spectrum
a band of energy ranging from gamma rays at the short-wave end of the spectrum to radio waves at the long-wave end
consciousness
our subjective experiences that stem from our perception
the hard problem of consciousness
How does the processing of stimuli through the activation of sensory receptors lead to perception?
step 1 of the perceptual process
stimulus in the environment: information about the distal stimulus is carried by light
step 2 of the perceptual process
Light is reflected and focused: the light is transformed into a proximal stimulus
step 3 of the perceptual process
Receptor processes: specialized sensory receptors respond to environmental energy, resulting in an electrical representation
step 4 of the perceptual process
Neural processing: changes occur as signals are transmitted through the maze of neurons
steps 5-7 of the perceptual process
Behavioural responses (perception, recognition, action): electrical signals are transformed into conscious experience
Materialism
there is only one reality & it is physical
Dualism
there is both a physical & mental reality. Our perceptions & thoughts are mental but everything else is physical
how is relationship A demonstrated by the oblique effect?
The oblique effect was demonstrated using grating acuity (the smallest width of lines that participants can detect)
how is relationship B demonstrated by the oblique effect?
The oblique effect was demonstrated using optical brain imaging; horizontal and vertical orientations caused larger brain responses
how is relationship C demonstrated by the oblique effect?
The oblique effect was demonstrated by measuring the brain response and behavioural sensitivity in the same participants. Behavioural measurements were made by decreasing the intensity difference between the light and dark, while the physiological response was measured using fMRI
weber
there is a constant difference threshold for different types of stimuli (you have to add _% of the original stimuli so that the difference is detectable)
different threshold constant for electrical shock
1%
different threshold constant for lifted weight
2%
different threshold constant for sound intensity
4%
different threshold constant for light intensity
8%
different threshold constant for taste
8%
Magnitude estimation and power function
the function of stimulus intensity and magnitude estimate
magnitude estimation for brightness
Brightness levels off after a while because it becomes so intense that you can no longer detect subsequent increases
magnitude estimation for line length
Line length continues increasing linearly
magnitude estimation for electric shock
Electric shock increases exponentially
difference threshold for dangerous stimuli
Things that are dangerous have a lower threshold for survival purposes
