Chapter 5 Psychology

Sensory Receptor Cells

specialized cells to convert (sensory transduction) specific stimuli into neural impulses

Sensation

the act of using our sensory systems to detect environmental stimuli

Transduction

transformation of physical energy into electrical signals

Psychophysics

the study of physical stimuli on sensory perceptions and mental states

Gustav Fechner

studied the strength of a stimulus and a person’s ability to detect it

Absolute Threshold

smallest amount of a stimulus that one can detect

Signal Detection Analysis

technique to determine the ability to separate true signals from background noise

Sensitivity

true ability to detect a presence or absence of signal

Response Bias

behavioural bias to respond yes

Difference Threshold or Just Noticeable Difference

minimal difference between two stimuli necessary for detection of a difference between the two

Weber’s Law

JND is constant proportion of original intensity

Perception

the conscious recognition and identification of a sensory stimulus

Bottom-up Processing

• outside-in

• sensory information from environment driving the process of understanding

• unconscious (hard to resist)

Top-down Processing

• inside-out

• knowledge and expectancy driving the process of understanding

• conscious (effortful)

Sensory Adaptation

a process whereby repeated stimulation of a sensory cell leads to a reduced response

Inattention Blindness

failure to notice something obvious because you were focused on something

• Simons and Chabris (Gorilla crossing into video)

Segall, Cambell, & Herskovits

Individual differences in perception

• thrill seekers are more likely to like sour flavours

• personality may impact perceptions

Frequency

associated with the sound’s pitch

Loudness

associated with the sound’s amplitude

Timbre

is a sounds purity and is affected by frequency, amplitude, and timing

Light Waves

• electromagnetic radiation produces light which is made up of particles called photons

• different wavelengths appear to us as different colours

• objects reflect and absorb light

Cornea

transparent covering over the eye, focuses light

Pupil

opening in eye through which light passes through

• varies based on light levels and arousal

• dilated = bigger, constricted = smaller

Iris

coloured portion of the eye, a muscle that controls pupil size

Lens

curved, transparent and provides additional focus

• attached to muscles

• focus on light from far objects

Accommodation

change in curvature of lens to focus light on retina, specifically the fovea (indentation in the back of the eye containing photoreceptors)

Retina

light sensitive lining of the eye (sheet of nerve cells containing receptors for vision)

• retina/fovea contains all receptor cells (rods and cones)

Cones

used for central and colour vision, fovea (centre of retina) is all cones

• light detection, acute detail, and spatial resolution

Rods

used for periphery and night vision, many more rods than cones, more responsive to dark and light

• movement in periphery

Ganglion Cells

send visual input yo the brain via the optic nerve (carries visual information to the brain)

Optic Chiasm

X-shaped structure, the point where the optic nerve from each eye met

• visual information is processed in parallel pathways (ie. right visual field is processed in the left hemisphere of the brain)

Trichromatic Theory

three different receptors for colour each respond to different wavelengths of light (blue, red, green)

• not likely as we can see many more than three colors

Opponent Process Theory

colour pairs work to inhibit one another

• green-red; blue-yellow; and black-white cannot be mixed

Afterimage

continuation of sensation once stimuli is removed

Depth Perception

perception of spatial relations in 3-D space

• front, below, beside, above, behind

Binocular Cues

• cues that rely on both eyes

• binocular disparity - slightly different stimuli recorded by the retina of each eye, provides us with a binocular cue of depth

Monocular Cues

cues that rely on one eye

• position, relative size, linear perspective, light and shadow, interposition, aerial perspective

Pinna (ear)

where sound waves are sourced

Tympanic Membrane

where sound waves enter the ear and deflect

Maleus, Incus, Stapes

vibrations set in motion these three ossicles (bones)

Oval Window

where the stapes hits, creating waves to form

Cochlea

fluid-filled part of the inner ear

Basilar Membrane/Hair Cells

communicate with nerves in the cochlea and send neural impulses to the brain

Temporal Theory

different frequencies are converted into different rates of action potentials (high frequency sounds = more rapid firing)

Place Theory

different frequencies activate different regions of the basilar membrane

brain equates the place activity occurred on the basilar membrane with a particular frequency

Monaural

sound’s source relative to body position

Binaural

relies on a horizontal axis by delivering different patterns of vibration between eardrums in each ear

Conductive Hearing Loss

problems delivering sound to cochlea

• infection, wax buildup, eardrum damage

• failure of vibration from eardrum to ossicles

Sensorineural Hearing Loss

transmission failure from cochlea to brain

• most common hearing loss

• aging, trauma, infection, noise exposure

Meniere’s Disease

degeneration of inner ear structures

• require cochlear implant to directly stimulate auditory nerve

Olfactory Sense + Gustatory Sense

• together are called the chemical senses because they involve responses to particular chemicals

• important for smelling or tasting rotten food, noxious gases, smoke

5 Taste Receptors

1. sweet

2. sour

3. bitter

4. salt

5. umami (MSG)

6. Fatty?

Papillae

bumps that cover the surface of the tongue

Taste Bud

clusters of sensory receptor cells (in the papillae) that bind the food molecules that dissolve in our saliva and turn this into a neural impulse (transduction)

Olfactory Receptor Neurons

the receptor cells bind odourant molecules into a neural impulse (transduction) and send that impulse to the brain

Pheromones

Chemical messages - often to signal

• the only reason Neave could have been attracted to Lucas

Olfactory Bulb

• tip of frontal lobe

•  sends information to amygdala and indirectly to the hippocampus

• smell can evoke memories

Ageusia

inability to taste

Anosmia

inability to smell, can still taste but not ‘flavours’

Tactile or Somatosensory System

combination of skin sense:

• pressure, touch, temperature, vibration, and pain

Pain Perception

• physical and psychological components

• inflammatory pain: tissue damage

• neuropathic pain: exaggerated signal of damage to neurons in PNS or CNS

• generally well developed at birth

• variability in detection and response

Fast Pathway (Pain Perception)

sharp, localized pain is felt quicker because it travels along myelinated neurons to the brain

Slow Pathway (Pain Perception)

nagging, burning pain is slower to be felt because it travels along unmyelinated pathways

Vestibular

ability to maintain balance and body posture

• located in semicircular canals of our inner ears

Proprioception

perception of body position

Kinaestesia

perception of body movement in space

Kinesthetic

receptor cells in your muscles tell the brain where we are moving and where our body parts are in space

Gestalt Psychology

• Vertheimer, Kohler, and Koffka

• perception helps us to add meaning to visual information by helping to organize it

• form patterns

• the whole is different from the sum of it’s parts

Figure Ground

something the main object or background

Similarity

stimuli resembling one another tend to be grouped together

Proximity

visual stimuli near to one another tend to be grouped together

Continuity

objects that continue a pattern are grouped together

Closure

we tend to fill in small gaps so they are perceived as wholes

Pattern Perception

ability to discriminate different figures and shapes

Perceptual Hypothesis

educated guesses that we make while interpreting sensory information

Perceptual Sets

readiness to interpret a certain stimulus in a certain way

• perception requires both bottom-up and top-down processes

Ames Room

we expect the room to be square, but it’s irregularly shaped, we also believe people in the room are the same distance from us