Task 1 - Measuring Experiences Flashcards
Sensation
The ability to detect stimulus and perhaps to turn that detection into a private experience – the bottom-up process by which our senses, like vision, hearing and smell, receive and relay outside stimuli
Perception
That act of giving meaning to a detected sensation – the top-down way our brains organize and interpret that information and put it into context
Dualism
the idea the mind has an existence separate from the material world of the body
Materialism
The idea that the only thing that exists is matter, and that all things, including the AND … consciousness, are the results of interaction between bits of matter
Panpsychism
the idea that the mind exists as a property of all matter – that is, that all matter has consciousness – belief that everything material, however small, has an element of individual consciousness
Psychophysics
The science of defining quantitative relationships between physical and psychological (subjective) events
Two-point touch threshold
the minimum distance at which two stimuli (e.g., two simultaneous touches) are just perceptible as separate
Just noticeable difference (JND) or difference threshold
the smallest detectable difference between two stimuli, or the minimum change in a stimulus that enables it to be correctly judged as different from a reference stimuli
Weber fraction
the constant of proportionality in Weber’s law – percentages
Weber’s law
the principle describing the relationship between stimulus and resulting sensation that says the just noticeable difference (JND) is a constant fraction of the comparison stimulus – he focused on a specific subset
- we perceive differences on a logarithmic, not linear scale – it’s not the amount of change but the percentage of change that matters
Fechner’s law
a principle describing the relationship between stimulus and resulting sensation that says the magnitude of subjective sensation increase proportionally to the logarithm of the stimulus intensity – extended version of weber’s law – he assumes that all JND are equal
Absolute threshold (of sensation)
the minimum amount of stimulation necessary for a person to detect a stimulus 50% of the time
Method of constant stimuli (Psychophysical method)
a psychophysical method in which many stimuli, ranging from rarely to almost always perceivably different from a reference stimulus, are presented one at a time. Participants respond to each presentation: “yes/no” “same/different” and so on
Method of limits (Psychophysical method)
a psychophysical method used in order to measure a subject’s perception of stimuli by determining at what level a stimulus is perceived by a subject. A stimulus is presented and increased or decreased until it is perceivable by the subject – a psychophysical method in which the particular dimension of a stimulus, or the difference between two stimuli, is varied incrementally until the participant responds differently
Method of adjustment (Psychophysical method)
a method of limits in which the subject controls the change in the stimulus – f.e. Adjusting the volume of the stereo
Psychophysical methods
- Method of constant stimuli
- Method of limits
- Method of adjustment
Scaling methods
Magnitude estimation
Magnitude estimation
a psychophysical method in which the participant assigns values according to perceived magnitudes of the stimuli – f.e., when cup A tastes twice as sweet as cup B, cup A needs double the amount of sugar as from cup B
Steven’s power law
a principle describing the relationship between stimulus and resulting sensation that says the magnitude of subjective sensation is proportional to the stimulus magnitude raised to an exponent
Cross-modality matching
the ability to match the intensities of sensations that come from different sensory modalities. This ability allows insight into sensory differences. For example, a listener might adjust the brightness of a light until it matches the loudness of a tone
Supertaster
supertasters are those individuals who experience the most intense taste sensations; for some stimuli, they are dramatically more intense than for medium tasters or nontasters. Supertasters also tend to experience more intense oral burn and oral touch sensations
Signal detection theory
a psychophysical theory that quantifies the response of an observer to the presentation of a signal in the presence of noise. Measures obtained from a series of presentations are sensitivity (d”) and criterion of the observer – a model for predicting how and when a person will detect weak stimuli, partly based on context
–> This theory exists to help us understand what’s going on when we make decisions under conditions of uncertainty
Criterion
In signal detection theory, an internal threshold that is set by the observer. If the internal response is above criterion, the observer gives one response (e.g., “yes, I hear that”). Below criterion, the observer gives another response (e.g., “no, I hear nothing”)
Sensitivity
In signal detection theory, a value that defines the ease with which an observer can tell the difference between the presence and absence of a stimulus or the difference between stimulus 1 and stimulus 2
Receiver operating characteristic (ROC) curve
in studies of signal detection, the graphical plot of the hit rate as a function of the false-alarm rate. If these are the same, points fall on the diagonal, indicating that the observer cannot tell the difference between the presence and absence of the signal. As the observer’s sensitivity increases, the curve bows upward toward the upper left corner. That point represents a perfect ability to distinguish signal from noise (100% hits, 0% false alarms)
Sine wave
a simple, smoothly changing oscillation that repeats across space. Higher frequency sine waves have more oscillations and lower frequencies have fewer oscillations over a given distance. 1. In hearing, waveform for which variation as a function of time is a sine function. Also called pure tone. 2. In vision, a pattern for which variation in a property like brightness or color as a function of space is a sine function
Wavelength
the distance required for one full cycle of oscillation for a sine wave
Period
for hearing, the time required for a full wavelength of an acoustic sine wave to pass by a point in space
Fourier analysis
These sine waves broken down into individual sine wave components is done through a process called Fourier analysis - a mathematical procedure by which a signal can be separated into component sine waves at different frequencies. Combining these sine waves will reproduce the original signal
Spatial frequency
the number of cycles of a grating per unit of visual angle (usually specified in cycles per degree)
Perceptual process
- environmental stimulus
- transformation / representation
- sensory receptor / transduction
- neural processing
- perception
- recognition
- action
- Environmental stimulus (Perceptual process)
Anything in the environment that we observe or sense
- -> stimulus detected based on light reflected off of it
- distal, proximal attended (what you focus on)
- Transformation / Representation (Perceptual process)
Transformation: Stimulus changes from environment to perception
Representation: Stimulus is formed based on receptors and nervous system
– everything perceived is not based on direct contact but on representation of stimulus on receptors
–> light is reflected and transformed
- Sensory receptor / Transduction
Sensory receptor: Nerve cells that respond to environmental energy
–>
Transduction: Change from environmental energy to electrical energy in the brain
- light is reflected from stimulus on retinal receptors
- transformation from light into electrical energy (transduction) through a visual pigment (which is a light sensitive chemical that transforms it into electrical energy)
- shape perception through the way the receptives respond to the stimulus
- Neural processing
Sensory receptors send electrical signals to the brain
visual receptors to network of neurons (2 steps: 1. network transmits signal, 2. can also change signal (neural processing) --> retina --> back of eye --> brain and forms an electrical signal --> temporal: hearing (auditory) parietal: touch frontal: all senses (combination) occiptial (vision)
- Perception
Conscious awareness - what we observe (behavioral response)
- Recognition
Provides meaning to what we observe – object categorized given meaning) (behavioral response)
- Action
To do something with your sensory experiences – necessary for survival (behavioral response)
