Chapter 7

What are the three basic principles that apply to all senses?

1. No one-to-one correspondence between physical and psychological reality. 2. Sensation and perception are active, not passive. 3. Sensation and perception are adaptive.

What is transduction in sensory systems?

The process by which sensory receptors respond to environmental stimuli and generate action potentials in adjacent sensory neurons.

Define absolute threshold.

The minimum amount of physical energy (stimulation) needed for an observer to notice a stimulus.

What does Weber's law state?

That for two stimuli to be perceived as differing in intensity, the second must differ from the first by a constant proportion.

What is sensory adaptation?

The tendency of sensory systems to respond less to stimuli that continue without change.

What role do rods and cones play in vision?

Rods are sensitive to light, allowing vision in dim light; cones are sensitive to particular wavelengths, producing color perception.

What are the two processing streams for visual information?

The 'what' pathway (determining what an object is) and the 'where' pathway (locating an object in space).

What is the difference between bottom-up processing and top-down processing?

Bottom-up processing begins with raw sensory data feeding up to the brain, while top-down processing starts with the observer's expectations and knowledge.

How do sound waves relate to pitch and loudness?

Frequency (in hertz) corresponds to pitch, while amplitude (in decibels) corresponds to loudness.

What is the function of the olfactory nerve?

It transmits information about smell from the olfactory receptor cells to the brain.

What does the gate-control theory explain?

It explains how the central nervous system regulates the experience of pain.

What is perceptual constancy?

The organization of changing sensations into percepts that are relatively stable in size, shape, and color.

What is the significance of feature detectors in perception?

They are specialized cells in the cortex that respond only to specific patterns or orientations of stimulation.

What is subliminal perception?

The tendency to perceive information outside our conscious awareness.

What is the principle of figure-ground perception?

It is a fundamental rule that states people tend to differentiate between an object (figure) and its background (ground).