Chapter 1- Introduction

Question 1

Sensation

Answer 1

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

Question 2

Perception

Answer 2

The act of giving meaning to a detected sensation.

Question 3

What are the six methods used to measure how sensitive our senses are?

Answer 3

Method 1: Thresholds
Method 2: Scaling- Measuring Private Experience
Method 3: Signal Detection Theory- Measuring Difficult Decisions
Method 4: Sensory Neuroscience
Method 5: Neuroimaging- An Image of the Mind
Method 6: Computational Models

Question 4

Qualia

Answer 4

In reference to philosophy, private conscious experiences of sensation or perception.

Question 5

Who is Gustav Fechner?

Answer 5

Thought to be the true founder of experimental psychology, he is best known for his pioneering work relating changes in the physical world to changes in our psychological experiences, thus inventing the field of psychophysics.

Question 6

Dualism

Answer 6

The idea that the mind has an existence separate from the material world of the body.

Question 7

Materialism

Answer 7

The idea that the only thing that exists is matter, and that all things, including the mind and consciousness, are the results of interaction between bits of matter.

Question 8

Panpsychism

Answer 8

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

Question 9

Psychophysics

Answer 9

The science of defining quantitative relationships between physical and psychological (subjective) events.

Question 10

Who is Ernst Weber?

Answer 10

He discovered the smallest detectable change in stimulus, such as the weight of an object, is a constant proportion of the stimulus level. This relationship later became known as Weber’s Law.

Question 11

Two-Point Touch Threshold

Answer 11

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

Question 12

Just Noticeable Difference (JND)

Answer 12

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

Question 13

Difference Threshold

Answer 13

Another term for the smallest change in stimulus that can be detected (In reference to the JND).

Question 14

Weber Fractions

Answer 14

The constant of proportionality in Weber’s Law.

Question 15

Weber’s Law

Answer 15

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.

Question 16

Fechner’s Law

Answer 16

A principle describing the relationship between stimulus and resulting sensation that says the magnitude of subjective sensation increases proportionally to the logarithm of the stimulus intensity.

Question 17

Units of physical entities versus measures of people’s perception.

Answer 17

Physical entities refer to things such as light or sound. Meanwhile people’s perception refers to things such as “brightness” or “loudness”.

Question 18

Frequency versus Pitch

Answer 18

Frequency is the measure of the rate of fluctuations in the physical sound pressure, while the pitch of a musical note describes a psychophysical response to that physical phenomenon.

Question 19

Absolute Threshold

Answer 19

The minimum amount of stimulation necessary for a person to detect a stimulus 50% of the time.

Question 20

Method of Constant Stimuli

Answer 20

A psychophysical method in which many stimuli, ranging from rarely to almost always perceivable (or 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.

Question 21

Method of Limits

Answer 21

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.

Question 22

Method of Adjustment

Answer 22

A method of limits in which the participant controls the change in the stimulus.

Question 23

Magnitude Estimation

Answer 23

A psychophysical method in which the participant assigns values according to perceived magnitudes in the stimuli.

Question 24

Steven’s Power Law

Answer 24

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.

Question 25

Compare Weber’s Fechner’s and Steven’s Laws

Answer 25

1) Weber’s law involves clear objective measurement. We know how much we varied the stimulus, and either the observers can tell the stimulus changed or they cannot.

2) Fechner’s law begins with the same sort of objective measurements as Weber’s, but the law is actually a calculation based on some assumptions about how sensation works. In particular, Fechner’s law assumes that al JNDs are perceptually equivalent. In fact, this assumption turns out sometimes to be incorrect and leads to instances where the “law” is violated…

3) Stevens’s power law describes rating data quite, well, but notice that rating data are qualitatively different form the data that support Weber’s law. We can record the observer’s ratings and we can check whether those ratings are reasonable and consistent, but there is no way to know whether they are objectively right or wrong.

Question 26

Cross-Modality Matching

Answer 26

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.

Question 27

Signal Detection Theory

Answer 27

A psychophysical theory that quantifies the response of an observer to the presentation of a signal in the presence of noise. Measures obtained form a series of presentations are sensitivity (d’) and criterion of the observer.

Question 28

Criterion

Answer 28

In reference to 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.)

Question 29

What are the four positive outcomes?

Answer 29

1) Correct rejection or true negative
2) Hit or true positive
3) False alarm or false positive
4) Miss or false negative.

Question 30

Sensitivity

Answer 30

In reference to signal detection theory, a measure 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.

Question 31

Receiver Operating Characteristic (ROC) Curve

Answer 31

In reference to 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).

Question 32

Doctrine of Specific Nerve Energies

Answer 32

A doctrine formulated by Johannes Muller, stating that the nature of a sensation depends on which sensory fibers are stimulated, rather than how they are stimulated.

Question 33

Cranial Nerves

Answer 33

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.

Question 34

Olfactory (I) Nerves

Answer 34

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 to the olfactory bulb.

Question 35

Optic (II) Nerves

Answer 35

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

Question 36

Oculomotor (III) Nerves

Answer 36

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 muscles of the upper eyelid, the ciliary muscle, and the sphincter muscle of the pupil.

Question 37

Vestibulocochlear (VIII) Nerves

Answer 37

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.

Question 38

Trochlear (IV) Nerves

Answer 38

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

Question 39

Abducens (VI) Nerves

Answer 39

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

Question 40

Warmth and Cold Fibers

Answer 40

These are two specialized types of nerve cells which respond to increases and decreases in temperature on the skin.

Question 41

Menthol

Answer 41

Imparts a minty flavor in cough drops and stimulates cold fibers so the skin feels cooler without getting physically colder.

Question 42

Capsaicin

Answer 42

A chemical that occurs naturally in chili peppers. It causes warmth fibers to fire, creating a sense of increasing heat even though the temperature has not changed.

Question 43

Polysensory

Answer 43

Referring to blending multiple sensory systems.

Question 44

Sensory Integration or Multi-Sensory Integration

Answer 44

The process of combining different sensory signals. The senses typically work together to learn about the world and to guide behavior. This is not the same as the mathematical process of integration learned in calculus (e.g., the integral of acceleration is velocity).

Question 45

Synapse

Answer 45

The junction between neurons that permits information transfer.

Question 46

Neurotransmitters

Answer 46

A chemical substance used in neuronal communication at synapses.

Question 47

Explain how neural firing works:

Answer 47

A neuron “fires” when a stimulus makes the voltage across a piece of the cell membrane a bit more positive than its negative “resting potential”. This is called depolarization. Depolarization permits sodium ions (Na+) to rush into the cell, thus increasing the voltage and generating an action potential. Very quickly afterward, potassium ion (K+) flow out of the cell, bringing the voltage back to the resting voltage. An action potential is analogous to a wave, sweeping across the ocean or around a football stadium. Here, the action potential sweeps along the length of the axon until it reaches the axon terminal.

Question 48

Neuroimaging

Answer 48

A set of method that generate 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.

Question 49

Electroencephalography (EEG)

Answer 49

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

Question 50

Event-Related Potential (ERP)

Answer 50

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

Question 51

Magnetoencephalography (MEG)

Answer 51

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

Question 52

Magnetic Resonance Imaging (MRI)

Answer 52

An imaging technique 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.

Question 53

fMRI

Answer 53

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

Question 54

Blood Oxygen Level-Dependent (BOLD) Signal

Answer 54

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

Question 55

Positron Emission Tomography (PET)

Answer 55

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

Question 56

Mathematical Model

Answer 56

The use of mathematical language and equations to describe psychological and/or neural processes.

Question 57

Computational Model

Answer 57

The use of mathematical language and equations to describe steps in psychological and/or neural processes (often implemented on a computer).

Question 58

Efficient Coding Models

Answer 58

Theoretical and/or computational models that explain neural processing by assuming that sensory systems become tuned to predictability in natural environments in ways that economically encode predictable sensory inputs while highlighting inputs that are less predictable.

Question 59

Bayesian Models

Answer 59

Theoretical and/or computational models that employ Bayesian statistical methods to generate an internal model of the source of sensory inputs based upon prior experience.

Question 60

Predictive Coding

Answer 60

The use of Bayesian models to predict future inputs. If predictions do not match inputs (prediction error), the model is adjusted to improve future predictions.

Question 61

Artificial Neural Networks (Connectionist Models)

Answer 61

Computational methods that consist of networks of nodes with weighted connections between them. Connection weights increase and decrease following experience in ways that resemble organization of biological neural networks.

Question 62

“Supervised” versus “Unsupervised”

Answer 62

If a model is given feedback when it is right or wrong, it is a “supervised” model; models without this feedback are “unsupervised”.

Question 63

Deep Neural Networks (DNNs)

Answer 63

Artificial neural networks that have a very large number of layers of nodes with millions of connections.