Chapter 5

Unit 4 - sensation and perception

sensation

  • Receiving or input of information from the environment

  • Environment information interacts with sensory receptors or specialised neurons

Eyes, Ears, Tongue, Nostrils, Skin

Perception

  • “Interpreting” or making sense of

  • Interpretation, evaluation, and organization of sensations

    • Guided by experience, intention, and action

    • Consciously experienced as highly individual and cultural

  • People organize sensations into a meaningful whole

Transduction

  • A process by which sensory receptors detect a specific stimuli and then convert that energy into an action potential which is sent to the central nervous system


Sensory systems

Complex network of sensory neurons, neural pathways, and parts of the brain

  • Vision

Process of light: Light energy is converted into electrical or neural signals by rods and cones

Rods

  • Located in the periphery of the retina

  • Sensitive to low light intensity

  • Detects shades of grey

  • Nighttime vision 

Cones

  • Located in the fovea

  • Sensitive to high light intensity

  • Detects color

    • 3 types: Sensitive to red, green, and blue light

Priceiples of color:

2 theories describe different parts of the visual system

  • Trichromatic theory of color (applies to the retina)

    • Cones have a preference for 3 colors: red, green, blue

    • All colors can be produced by combining these 3 colors

    • Colorblindness occurs when one or more type of cone is missing: most common: red-green color blindness

  • Opponent-process theory of color (cells after the retina)

    • Cones respond to pairs of colors: red-green- blue-yellow, black-white

  • Hearing (audition)

Process of sound waves

  • Outer ear (pinna and tympanic membrane): Collects sound waves and helps locate where sound is by using differences between ears on either side of head

  • Middle ear (ossicles): Amplify sound waves

  • Inner ear (cochlea and basilar membrane): Codes sound waves into neural messages, messages sent to thalamus and auditory cortex (temporal lobe)

    • Also responsible for balance

Translating sound wave

  • 3 components of sound waves

    • Frequency (pitch) - Length of the sound wave (wavelength) 

    • Amplitude (volume) - Height of the sound wave

    • Complexity (timbre) - Mixture of tones

  • Smell (olfaction)

  • Taste (gustation)

  • Touch (somatosensation)

  • Balance (vestibular sense)

  • Body position (proprioception)

  • Movement (kinesthesia)

  • Pain (nociception)

  • Temperature (thermoception)