Chapter 4: Sense and Perception

What is sensation?

Sensation is the stimulation of the sense organs.

What is perception?

Perception is the selection, organization, and interpretation of sensory input.

psychophysics

methods that systematically relate the physical characteristics of a stimulus to an observer’s perception

Who is Gustav Fechner?

Gustav Fechner is known for his work in psychophysics, particularly his book 'Elemente der Psychophysik' (1860).

absolute threshold

the minimal intensity needed to just barely detect a stimulus in 50% of the trials

What is Just Noticeable Difference (JND)?

the minimal change in a stimulus (e.g., its loudness or brightness) that can just barely be detected.

What does Weber's Law state?

for every sense domain, the change in a stimulus that is just noticeable is a constant proportion despite variation in intensities

What does Fechner’s Law describe?

Fechner's Law states that subjective sensation is proportional to the logarithm of the stimulus intensity.

What is Signal Detection Theory?

the response to a stimulus depends both on a person’s sensitivity to the stimulus in the presence of noise and on a person’s decision criterion

What is subliminal perception?

Subliminal perception is the registration of sensory input without conscious awareness.

What is the role of sound amplitude?

Amplitude affects the perception of loudness.

How is pitch defined in relation to sound?

Pitch depends on the frequency of sound waves.

What is Place Theory in hearing?

Place Theory suggests that the perception of pitch corresponds to the vibration of different portions along the basilar membrane.

What is Frequency Theory in hearing?

Frequency Theory suggests that pitch perception corresponds to the rate at which the entire basilar membrane vibrates.

What is the definition of gustatory system?

The gustatory system is the sensory system for taste.

What do pheromones do?

Pheromones are chemical messages sent by one organism and received by another of the same species.

What is the role of the vestibular system?

The vestibular system responds to gravity and keeps you informed of your body’s location in space.

What is depth perception?

Depth perception is the interpretation of visual cues that indicate how near or far away objects are.

What are the three main parts of the ear?

The three main parts of the ear are the outer ear, middle ear, and inner ear.

What is the function of the outer ear?

The outer ear collects sound waves and directs them into the ear canal.

What is the role of the middle ear?

The middle ear contains the ossicles, which amplify and transmit sound vibrations to the inner ear.

What structures are located in the inner ear?

The inner ear contains the cochlea, vestibule, and semicircular canals.

What is the cochlea responsible for?

The cochlea is responsible for converting sound vibrations into neural signals for the brain.

What are the main parts of the eye?

The main parts of the eye include the cornea, lens, retina, iris, and pupil.

What is the function of the cornea?

The cornea helps to focus light as it enters the eye and provides most of the eye's optical power.

What role does the lens play in the eye?

The lens adjusts its shape to focus light onto the retina, allowing for clear vision at various distances.

What is the retina, and what is its function?

The retina is a thin layer of tissue at the back of the eye that detects light and converts it into neural signals.

What is the purpose of the iris?

The iris controls the size of the pupil and, consequently, the amount of light that enters the eye.

transduction

when sense receptors convert physical signals from the environment into neural signals that are sent to the central nervous system

sensory adaptation

sensitivity to prolonged stimulation tends to decline over time as an organism adapts to current (unchanging) conditions