Psychology of Sensation and Perception Terms Chapter 1 Wolfe

Sensation

The ability to detect a stimulus and, perhaps, to turn that detection into a private experience

Perception

The act of giving meaning to a detected sensation

Thresholds, Scaling, Signal detection theory, Sensory Neuroscience, and Neuroimaging

The variety of methods used to study the sense of participants

Thresholds

The method by which private experience is measured by assessing the levels at which stimulus becomes undetectable

Scaling

The method by which private experience is measured by comparing the personal perception of stimulus to measure differentiation in the sample

Signal Detection Theory (SDT)

The method by which private experience is measured by assessing difficult decisions and how they occur based on stimulus received

Sensory Neuroscience

The method by which private experience is measured by assessing the ways sensory receptors and nerves undergird your perceptual experience

Neuroimaging

The use of various techniques to provide pictures of the structure and function of the living brain

Qualia(quale)

A philosophical concept describing private conscious experiences of sensation or perception

Dualism

The ideal that 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 mind and consciousness, are the result of interaction between matter

Panpsychism

The idea that the mind exists as a property of all matter - that is, that all matter has consciousness

Psychophysics

The study of defining qualitative relationships between physical and psychological (subjective) events

Two-Point Touch Threshold

The minimum distance at which two stimuli (e.g., simultaneous touches) are just perceptible as separate

Just Noticeable Difference Threshold (JND)/Difference Threshold

The smallest detectable difference between two stimuli, or the minimum chance in a stimulus that enables it to be correctly judged as different from a reference stimulus

Weber Fraction

The constant of proportionality in Weber's law

Weber's Law

The principle describing the relationship between stimulus and resulting sensation that says the JND is a constant fraction of comparison stimulus

Fechner's Law

A principle describing the relationship between stimulus and resulting sensation that says the magnitude of sensation increases proportionally to the the logarithm of stimulus intensity, S = K Log R

Absolute Threshold

The minimum intensity of a stimulus that can be detected 50% of the time

Method of Constant Stimuli

A psychophysical method in which many stimuli, ranging from rarely to almost always perceivably different from a reference stimulus are presented on at a time.

Method of Limits

A psychophysical method of which the particular dimension of a stimulus or the difference between two stimuli, is varied incrementally until the participant responds differently

Method of Adjustment

A method of limits in which the subject controls the change in the stimulus

Magnitude Estimation

A psychophysical method in which the participant assigns values according to the perceived magnitude of the stimuli

Stevens' Power Law

A principle describing the relationship between stimulus and the resulting sensation that says the magnitude of subjective sensation is proportional to the stimulus magnitude raised to an exponent

Stevens' Power Law Equation

S = a ( I ) ^ B

S= Sensation, I = Stimulus Intensity

Cross-Modality Matching

The ability to match the intensity 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

Super-tasters are those individuals who experience the most intense taste sensations for some stimuli they are dramatically more intense than for medium tasters or non-tasters. Superstatsters also tend to experience more intense oral burn and oral touch sensation.

Signal Detection Theory

A psychophysical theory that qualifies 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 and the criterion of the observer

Criterion

In signal detection theory, an internal threshold 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 ("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

Reciever 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 a 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 a point in space

Phase

A fraction of the cycle of the sine wave described in degrees (0° to 360°) or radians (0π to 2π). In hearing phase can be used to describe fractions of a period that relate to time

Fourier Analysis

A mathematical procedure by which any signal can be separated into component sine waves at different frequencies. Combining those sine waves will reproduce the original signal

Spatial Frequency

The number of cycles of grating per unit of visual angle (usually specified in cycles per degree)

Cycles Per Degree

The number of pairs of dark and bright bars per degree of visual angle

Doctrine of Specific Nerve Energies

A doctrine formulated by Johannes Müller, Stating that the nature of a sensation depends on which sensory fibers are stimulated, not on how fibers are stimulated.

Cranial Nerves

Twelve pairs of nerves (one for each side of the body) that originate in the brain stem and reach sense organs and muscles through openings in the skull

Olfactory Nerves

The first pair of cranial nerves. The axons of the olfactory sensory neurons bundle together after passing through the cribriform plate to form the olfactory nerve, which conducts impulses from the olfactory epithelia in the nose of the olfactory bulb.

Optic Nerves

The second pair of cranial nerves, which arise from the retina and carry visual information to the thalamus and other parts of the brain

Vestibulocochlear Nerves

The eighth pair of cranial nerves, which connect the inner ear with the brain transmitting impulses concerned with hearing and spatial orientation. The vestibulocochlear nerve is composed of the cochlear nerve branch and the vestibular nerve branch

Oculomotor Nerves

The third pair of cranial nerves, which innervate all the extrinsic muscles of the eye except the lateral rectus and the superior oblique muscles, and which innervate the elevator muscle of the upper eyelid, the ciliary muscle, and the sphincter muscle of the pupil

Trochlear Nerves

The fourth pair of cranial nerves, which innervate the superior oblique muscles of the eyeballs

Abducens Nerves

The sixth pair of cranial nerves, which innervate the lateral rectus muscle of the eyeballs

Polysensory

Referring to the blending multiple sensory systems

Vitalism

The idea that there is a force of life that is distinct from physical entities

Synapse

The junction between neurons that permits information transfer

Neurotransmitters

A chemical substance used in neuronal communication at synapses

Neuroimaging (II)

A set of methods that generates images of the structure and/or function of the brain. In many cases these methods allow us to examine the brain in living behaving humans

Electroencephalography (EEG)

A technique that, using many electrodes on the scalp, measures electrical activity from populations of many neurons in the brain.

Event-Related Potential (ERP)

A measure of electrical activity from a subpopulation of neurons in response to particular stimuli that requires averaging many EEG recordings

Magnetoencephalography (MEG)

A technique, similar to electroencephalography (EEG), that measures changes in magnetic activity across populations of many neurons in the brain

Computed Tomography (CT)

An imaging technology that uses X-rays to create images of slices through volumes of material (e.g., the human body)

Magnetic Resonance Imaging (MRI)

An imaging technology that uses the responses of atoms to strong magnetic fields to form images of structures like the brain. The method can be adapted to measure activity in the brain, as well.

Functional Magnetic Resonance Imaging (fMRI)

A variant of magnetic resonance imaging that makes it possible to measure localized patterns in activity in the brain. Activated neurons provoke increased blood flow, which can be qualified by measuring changes in the response of oxygenated/deoxygenated blood to strong magnetic fields

Blood Oxygen Level-Dependent (BOLD) Signal

The ratio of oxygenated to deoxygenated hemoglobin that permits the localization of brain neurons that are most involved in a task

Positron Emission Tomography (PET)

An imaging technology that enables us to define locations in the brain where neurons are especially active by measuring the metabolism of brain cells using safe radioactive isotopes