Sense and Perception

Sense:

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment

Vestibular Sense:

Your sense of whole body balance and equilibrium (governed mostly in the semicircular canals in the inner ear, but also in the Cerebellum, in the oldest part of the brain.

Kinesthetic Sense:

Your sense of body part position and movement (the receptors for this are all over the skin)

Sensory Receptors:

Sensory nerve endings that responds to stimuli

Perception:

The process by which out brain organizes and interprets sensory information, enabling us to recognize objects and events as meaningful

Bottom-up processing:

Information processing that begins with the sensory receptors and works up to the brain’s integration of sensory information

Top-down processing:

Information processing guided by higher-level mental processes

Weber’s Law:

The intensity of the just noticeable difference depends on how large the stimulus is to begin with

HEARING:

  • Like other senses, our hearing or audition, helps us adapt and survive
  • Hearing provides information and enables relationships

How it works:

  • Air molecules, each bumping into the next, create waves of compressed and expanded air, like the ripples on a pond circling out from a tossed river
  • As we swim in our ocean of moving air molecules, our ears detect these brief air pauses

Sound waves:

  • Frequency: The number of complete wavelengths that pass a point in a given time
  • Pitch: A tone’s experienced highness or lowness; depends on frequency

Ear hair:

  • Ear hair is what converts sound waves into electrical impulses (transduction) in the cochlea
  • Eventually thin/fall out due to age, same way hair off the top of the head falls off

Selective Attention:

  • Focusing conscious awareness on a particular stimulus to the exclusion of others

Inattentional blindness:

  • The inability to see an object or a person in out mindset

SEEING

Electromagnetic energy

  • When you look at a bright red tulip, the stimuli striking your eyes are not particles of the color red, but pulses of electromagnetic energy that your visual system perceives as red

  • On the other end are the mile-long waves of radio transmission

  • In between is the narrow band visible to us. Other portions are visible to other animals

  • What we see as a visible light is but a thing slice of the wide spectrum of electromagnetic energy. On the spectrum’s one end are the short gamma waves, no longer than the diameter of an atom

    Wavelength and Hue

  • Light travels in waves, and the shape of those waves influences what we see. Light’s wavelength is the distance from one wave peak to the next

  • More narrow sound waves are cooler colors like blue, while longer wavelengths are hotter colors like red

  • A light wave’s amplitude, or height determines its intensity-the amount of energy your eye receives

The Eye

  • Light enters the eye though the cornea, which bends light to help provide focus

  • Cornea

    • The eye’s clear, protective, other later covering the pupil and iris

    • Light then passes through the pupil, a small adjustable opening

  • Pupil

    • The adjustable opening in the center of your eye through which light enters

    • Surrounding the pupil and controlling its size is the iris, a colored muscle that dilates or constricts in response to light intensity

    • Each iris is so distinctive that an iris-scanning machine can confirm your identity

  • Iris

    • ring of muscle tissue that forms the colored portion of the eye round the pupil and controls the size of the pupil opening

    • After passing through your pupil, light hits the transparent lens in your eye. The lens then focuses the light rays into an image on your retina

    • Lens: the transparent structure behind the pupil that changes shape to help focus images in the retina

    • Retina, a multi-layered tissue on the eyeball’s sensitive inner surface. To focus the rays, the lens changes its curvature and thickness in a process called accommodation

  • Retina

    • The light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the profession of visual information

  • Rods

    • Retinal receptors that detect black, white, and gray, and are sensitive to movement; necessary for peripheral and twilight vision, when cones don’t respond

  • Cones

    • Retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions

    • Cones detect fine detail and give rise to color sensations

    • The rods and cones trigger chemical changes

    • That chemical reaction would spark neural signals in nearby bipolar cells

    • You could then watch the bipolar cells activate neighboring ganglion cells, whose axons twine together like the strands of a tope to form the optic nerve

  • Optic Nerve

    • The nerve that carries neural impulses from the eye to the brain

TASTE:

  • Taste is a chemical sense

  • Your brain does not taste, your tongue does

  • Taste buds

  • Your taste buds detect 5 tastes: sweet, bitter, umomi, sour, and salty

  • Papillae holds the taste bud

  • Gustatory nerves connect your taste buds to the spine

  • Processing is done in the frontal lobe (memory)

Why do we love salty and sweet and dislike bitter and sour:

  • Sweet

    • Our mothers milk is sweet, So sweet is the first taste we are given in life. So we crave it early on.

  • Salt

    • Is essential for our survival

  • Bitter

    • Most things out in the world that are poisonous to the human body taste bitter

  • Sour

    • Detecting unripe/unsafe food

SMELL:

Olfactory Cells

  • Neurons that project from the brain that process odor molecules

TOUCH:

  • The sensation produced by contact of an object with the surface of the skin

  • Sensitivity to touch varies in different parts of the body; For example, the lips and fingers are far more sensitive than the torso or back. See also touch sense

  • It is our physical connection to the outside world

  • Your skin is embedded with receptors that respond to various kinds of stimulation

  • The basic touch senses are:

    • Pain

    • Pressure

    • Texture

    • Temperature

Somatosensory Cortex:

  • Front of the parietal lobe

Three Types of Pain:

  • Biological

    Sensory receptors called nociceptors - mostly in your skin, but also in your muscles and organ - detect hurtful temperatures, pressure, or chemicals

  • Psychological

    • One powerful influence on out perception of pain is the attention we focus on it

    • Cultural Influences

      • Pain is a product of our attention, our expectations, and also our culture

      • Not surprisingly, then, our perception of pain varies with out social situation and out cultural traditions

      • We tend to perceive more pain when others seem to be experiencing again