Chapter 2: Sensation and Perception Flashcards
Define sensation.
Aligns with transduction, which is the conversion of physical, electromagnetic, auditory, and other information from our internal and external environment to electrical signals in the nervous system
What performs sensation?
Performed by receptors in the PNS, which forward the stimuli to the CNS in the form of action potentials and neurotransmitters
What is the term that best defines a raw signal?
Sensation
Define perception.
Refers to the processing of information to make sense of its significance.
Define ganglia.
Collections of neuron cell bodies found outside the CNS
How do sensory receptors transmit information?
Receive stimulus, and transmit the data to the CNS through sensory ganglia
What happens once transduction occurs?
Electrochemical energy is sent along neural pathways to various projection areas in the brain, which further analyze sensory input
What do photoreceptors respond to?
Electromagnetic waves in the visible spectrum (sight)
What do hair cells respond to?
Movement of fluid in the inner ear structures (hearing, rotational and linear acceleration)
What do nociceptors respond to?
Painful or noxious stimuli (somatosensation)
What do thermoreceptors respond to?
Changes in temperature (somatosensation)
What do osmoreceptors respond to?
Osmolarity of blood (water homeostasis)
What do olfactory receptors respond to?
Volatile compounds (smell)
What do taste receptors respond to?
Dissolved compounds (taste)
Define threshold.
The minimum amount of a stimulus that renders a difference in perception
What are the three types of thresholds?
- Absolute threshold
- Threshold of conscious perception
- Difference threshold
Define the absolute threshold.
Minimum of stimulus energy that is needed to activate a sensory system (at which a stimulus will be transduced and converted into action potentials)
What kind of threshold is this? We’re talking about how bright, loud, or intense a stimulus must be before it is sensed.
Absolute threshold
Define the threshold of conscious perception. What is it also called?
- Stimulus below the threshold of conscious perception arrives at the CNS, but does not reach the higher-order brain regions that control attention and consciousness
- Subliminal perception
Define the difference threshold. What is it also called called?
- Minimum difference in magnitude between two stimuli before one can perceive this difference
- Just-noticeable difference
What does Weber’s law state?
- There is a constant ratio between the change in stimulus magnitude needed to produce a jnd and the magnitude of original stimulus.
- For higher-magnitude stimuli, the actual difference must be larger to produce a jnd
What does the signal detection theory state?
Focuses on the changes in our perception of the same stimuli depending on both internal (psychological) and external (environmental) context
Define response bias.
Refers to the tendency of subjects to systematically respond to a stimulus in a particular way due to nonsensory factors.
What are catch trials? What are noise trials?
Catch trials: signal is presented
Noise trials: signal is not present