Signal detection theory:

a psychophysical theory that quantifies the response of an observer to the presentation of a signal in the presence of noise

Monism

The idea that the mind and matter are formed from, or reducible to, a single ultimate substance or principle of being

Materialism

• The idea that physical matter is the only reality,
• everything including the mind can be explained in terms of matter and physical phenomena.

Mentalism:

• Another form of monism
• The idea that the mind is the true reality
• objects exist only as aspects of the mind’s awareness

Mind–body dualism:

• Originated by Descartes
• the idea positing the existence of two distinct principles of
  being in the universe
  • spirit/soul and matter/body

Perception and your sense of reality are the products of
evolution

• Sensory systems provide a survival advantage
• Importance of type of energy in the environment
  for an animal determines which senses have
  developed
• Human senses are limited to only certain kinds of
  energy in the environment
  • Therefore, humans’ sense of reality is also limited

Adaptation:

• A reduction in response caused by
  prior or continuing stimulation
• No change in stimulation = our senses
  adapt
  • we no longer notice the stimulation

Nativism:

• the mind produces ideas that are not derived from external sources
• we have abilities that are innate and not learned

Dualism:

both mind and body exist and are separate entities

René Descartes (1596– 1650)

• argued for mind-body dualism,
• the universe consists of spirit/soul and matter/body

Empiricism

• All knowledge comes through the senses (perception)
  
  • Opposed to nativism, which says that some
    knowledge is innate

Thomas Hobbes (1588–1678)

• believed that everything that could ever be known or imagined had to be learned through the senses

John Locke (1632–1704)

• aim to explain how all thoughts, even complex ones, could be constructed from EXPERIENCE with a collection of sensations

George Berkeley (1685–1753)

• studied ways in which perception is limited to the information available to us through our eyes
  • All of our knowledge about the world must come from experience, (no matter how limited perception may be)

Thresholds:

Finding the limits of what can be perceived.

Scaling:

Measuring private experience.

Signal detection theory:

Measuring difficult decisions.

Sensory neuroscience:

The biology of sensation and perception.

Neuroimaging:

An image of the mind

Development:

Change across the lifespan.

Gustav Fechner (1801–1887)

• invented “psychophysics”
• considered to be the true founder of experimental psychology

Psychophysics:

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

Dualism:

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

Materialism:

• The only thing that exists is matter
• all things, including mind and consciousness = interactions between bits of matter.

Panpsychism:

• The mind exists as a property of all matter
  • all matter has consciousness.
    

Psychophysics adopted several new concepts for understanding sensation and perception.

1. Two-point threshold
2. Just noticeable difference (JND)
3. Absolute threshold

Two-point threshold:

• the minimum distance at which two stimuli (e.g., two
  simultaneous touches) can be distinguished

Just noticeable difference (JND):

• The smallest detectable difference between
  two stimuli, or the minimum change in a
  stimulus
  • that can be correctly judged as
    different from a reference stimulus
  • also known as difference threshold.

Absolute threshold:

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

Ernst Weber (1795–1878)

• “Weber’s Law”
  • the smallest change in a stimulus (that can be detected) = a constant proportion of the stimulus level
• As stimulus level increases or
  decreases,
  • the magnitude of change must increase proportionately = remain
    noticeable

Fechner’s law:

• principle describing the relationship between
  stimulus magnitude and resulting sensation magnitude
  • that the magnitude of subjective sensation increases
    proportionally to stimulus intensity (logarithm)

Method of constant stimuli

• many stimuli = rarely to always perceivable
• presented one at a time
  • "I don't hear it." => "I hear it."

Method of limits:

• magnitude/difference btn 2 stimuli varied incrementally
  • until participant responds differently

Magnitude estimation:

• The participant assigns values according to the perceived magnitudes of the stimuli
• S = al^b

Cross-modality matching:

The participant matches the intensity of a sensation in one sensory modality
with the intensity of a sensation in another

Signal detection theory:

• A psychophysical theory that
  quantifies the response of an observer to the presentation
  of a signal in the presence of noise

Four possible stimulus/response situations

1. Hit
2. Miss
3. False Alarm
4. Correct Junction

Four possible stimulus/response situations: HIT

• Stimulus is presented
• observer responds “Yes”

Four possible stimulus/response situations: MISS

• Stimulus is presented
• observer responds “No”

Four possible stimulus/response situations: FALSE ALARM

• Stimulus is not presented
• observer responds “Yes”

Four possible stimulus/response situations: CORRECT REJECTION

• Stimulus is not presented
• observer responds “No”

Receiver operating characteristic:

• In studies of signal detection,
• the graphical plot of the hit rate as a function of the false alarm rate

Stevens’ power law:

• A principle describing the
  relationship between stimulus magnitude + resulting
  sensation magnitude
• the magnitude of
  subjective sensation = proportional to the stimulus
  magnitude raised to an exponent

Cranial nerves:

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

Sensory information nerves

• Olfactory (I) nerves
• Optic (II) nerves
• Auditory (VIII) nerves

Muscles that move the eyes nerves

• Oculomotor (III)
• Trochlear (IV) nerves
• Abducens (VI) nerves

Hermann von Helmholtz (1821–1894)

• First person to measure the speed of neural impulses
• Invented the ophthalmoscope
• Wrote On the Sensations of Tone (1863)
  • one of the first studies of auditory perception

Santiago Ramón y Cajal (1852–1934)

• Created incredibly detailed drawings of neurons and neural structure

Synapse:

The junction between neurons that permits information transfer

Neurotransmitter:

A chemical substance used in
neuronal communication at synapses

Detection types

• method of constant stimuli
• method of limits
• SDT
• adaptive testing

Discrimination

• weber's law
• choice response time

Scaling

• fechner's law (indirect)
• Stevens' Law (direct)

Indentification

• information theory
• channel capacity
• identification time

two point threshold

the minimum distance at which 2 stimuli can be distinguished

reciever operating characteristic (ROC)

• in studies of signal detection
• the graphical plot of the hit rate as a function of the false alarm rate
• good performance (high sensitivity) "bows out" towards upper left corner

Sensitivity

• a values that defines the ease with which an observer can tell the difference between the presence and absence of a stimulus
  • difference between stimulus 1 and stimulus 2

Criterion

• an internal threshold that is set by the observer
  • internal response above criterion => observer gives 1 response
  • below criterion => observer gives another response

Doctrine of specific nerve energies

• Johannes Muller
• nature of a sensation depends on what sensory fibers are stimulated
  • not how fibers are stimulated
• auditory nerves = auditory info