Intro to Psych: Brain & Cognition (CH 4)

What is attention?

The active and conscious processing of information that binds individual features into a single perception

What is sensation?

A simple stimulation of a sense organ by the environment

What is perception?

An active & complex process in the brain: Organisation, identification, and interpretation of sensations to form mental representations.

What is Transduction?

Sense receptors convert physical environmental signals into neural signals for the CNS (brain)

What is Psychophysics?

Systematic study of the relationship between physical characteristics of a stimulus and psychological experience

What are the two types of peripheral nerve fibers and their roles in pain perception?

A-delta fibers (transmit initial, sharp pain) + C fibers (transmit longer-lasting, duller, throbbing pain)

Explain what referred pain is

sensory information from internal organs and external areas converges on the same nerve cells in the spinal cord. Internal pain is felt externally.

What is the gate-control theory?

pain perception is modulated by a neural gate at the spinal cord; this gate can be blocked or opened so pain signals can be transmitted to the brain

What is proprioception?

Our sense of body position that relies on receptors in muscles, tendons and joints

Explain the 2 types of hearing losses

Conductive - damage to eardrum or ossicles, preventing effective conduction of sound waves to the cochlea.

Sensorineural - damage to auditory nerve, inner hair cells or cochlea. Treated with cochlear implant.

What is haptic perception?

active exploration of the environment by touch through thermoreceptors

What is the role of the outer ear?

pinna & auditory canal (funnels soundwaves to eardrum)

What is the role of the middle ear?

ossicles (small bones) that: transmit and amplify vibrations + transfer the airborne wave into a pressure wave in the fluid of the inner ear.

What is the role of the inner ear?

Spiral-shaped cochlea (fluid filled tube containing basilar membrane) → basilar membrane undulates which stimulates thousands of inner hair cells → transduction → area A1 (primary auditory cortex in temporal lobe) → brain deciphers pitch using a place code (info about which part of the basilar membrane is most active) & temporal code (timing of action potential)

Explain the chemical process of smell

odorant molecules dissolve in mucous membrane of the olfactory epithelium → bind to olfactory receptor neurons → transduction → axons converge in olfactory bulb (direct outputs to emotional & memory centers of the brain)

What are the six criteria for Gestalt Psychology on visual perception and recognition?

Simplicity, continuity, closure, similarity, proximity, and common fate

What is the absolute threshold?

The minimum intensity (lowest level of energy) of a stimulus that organisms can detect 50% of the time

What is Just noticeable change (JND)?

The smallest change in a stimulus (e.g. brightness or loudness) that can be just barely detected.

What is Weber’s law?

The JND is a constant proportion to the stimulus’ original intensity (a more intense stimulus would need larger change for a difference to be noticed).

What is the difference between perceptual constancy, perceptual contrast, and perceptual organisation?

perceptual constancy - perceive objects having same shape, size and colour despite visual variations

Perceptual contrast - objects distinguished despite having similar sensory information

perceptual organisation - features are grouped to form objects

What are the monocular depth cues?

1. Relative size (smaller=further away)

2. linear perspective (parallel lines converge in the distance)

3. texture gradient (texture decreases as distance increases)

4. interposition (blocking object seen as closer)

5. relative height (objects lower in visual field seen as closer)

In the Ames room, people who are the same size seem to have very different heights. Why is this so?

A) Because in the Ames Room, perception is organised according to the Gestalt law of similarity.

B) Because the Ames Room exploits the monocular cue depth cue indicating that people who are farther away are perceived as smaller.

C) Because in the Ames Room linear perspective is tampered with.

Answer: C