Student Library

5.1 Sensation vs. Perception

4 min read

Sensation

  • occurs when sensory information is detected by a sensory receptor
    example: when light hits the cells of the eye

  • sensory receptor cells convert sensory stimuli information into action potentials

    • this process is known as transduction.

  • The body has more than five senses:

    • vision governs sight
    • audition governs hearing
    • olfaction governs smell
    • gustation governs taste
    • somatosensation governs touch
    • proprioception governs body position
    • kinesthesia governs movement
    • nociception governs the sense of pain
    • thermoception governs sense of temperature
    • the vestibular sense governs balance

Sensitivity

  • tells us the extent of a sensory system to detect stimuli from the environment
  • it can be expressed as absolute threshold or difference threshold depending on the context.

Absolute Threshold

  • the minimum amount of stimulus energy needed for the stimulus to be perceived 50% of the time
  • this can only be measured under incredibly controlled environments and conditions
  • messages that do not excite our sensory receptors (which then send nerve impulses in the brain) are called subliminal
    • we can receive subliminal messages yet we are not aware of it

Difference Threshold

  • the difference in stimuli required to be able to distinguish a difference between them
  • this simply states that our ability to notice or sense changes in the environment depends on the strength or intensity of a stimulus.
    (example: you would easily recognize a chime sound from afar in a tranquil night than in the busiest days.)
  • proposed by Ernst Weber in the 1830s and became his popular law, Weber’s law.

Perception

  • refers to how sensory information is organized, interpreted and experienced.
  • may involve two types of processing: bottom-up and top-down.

Bottom-up Processing

  • sensory information from a stimulus in the environment drives a process.
  • using basic features of our stimuli then we integrate them.
  • example: the smell of burning wood made people rush outside the building
    this indicated that the smoke from the environment (stimulus) caused people to rush outside the building (process)

Top-down Processing

  • knowledge or expectations is what drives a process
  • previous experience or expectations are used to recognize stimuli.
  • example: looking for a book in the library might require you to refer to your knowledge of the Dewey Decimal System
    this indicated that knowing the Dewey Decimal System (prior knowledge) might narrow your places in finding a certain book

Sensation versus Perception sensation physical and perception psychological.

Example:

Upon walking into a kitchen and smelling the scent of baking cinnamon rolls, the sensation is the scent receptors detecting the odor of cinnamon, but the perception may be “Mmm, this smells like the bread Grandma used to bake when the family gathered for holidays.”

Factors Affecting Perception

  • Some factors may affect us from perceiving the same stimuli.

Sensory Adaptation

  • happens when we gradually lose our ability to perceive a stimulus as our senses receive that same stimuli for an extended period of time
  • Example: the constant buzz of the fridge may be extremely noticeable when you first bought it compared to a year after you bought it.
    • The fridge is still buzzing but you no longer perceive the changes in sound as much as before.

Attention

  • the concentration of awareness on a phenomenon that leads to exclusion of other stimuli.
  • when we pay attention to something, we focus our awareness into one thing but also risk tuning out other sensory information that might be present
  • Example: when listening to music during class, you might be immersed in the melody playing in your ear but risk not perceiving the voice of your teacher discussing in the room.
    • The voice of your teacher hadn’t went away; however, you might fail to notice it just because you were actively listening to something else.
  • Inattentional Blindness is a phenomena when we fail to notice something completely visible just because we were actively attending to something else.

Motivation

  • an internal state that propels individuals to engage in goal-directed behavior.

  • our motivation to detect meaningful stimulus can shift our ability to differentiate between a true sensory stimulus and background noise

  • Example: When you’re expecting a phone call and, while you’re on the shower, you think the phone was ringing when it’s not.

  • our ability to recognize a stimulus from distracting background noise is called signal detection theory.

  • Some other factors that can affect our perceptions are:

    • beliefs,
    • values,
    • prejudices,
    • expectations,
    • life experiences

Graph View