Why Is Perception Critical

Question 1

what is sensation

Answer 1

the ability to detect a stimulus and perhaps turn that detection to a private experience

Question 2

what is perception

Answer 2

the act of giving meaning to a particular sensation

Question 3

what we use for research

Answer 3

1. thresholds
2. sensory neuroscience and neuroimaging
3. computational models

Question 4

threshold

Answer 4

finding the limits of what can be perceived

Question 5

sensory neuroscience and neuroimaging

Answer 5

the biology of sensation and perception

Question 6

computational models

Answer 6

using math and computation to understand perception

Question 7

two point threshold

Answer 7

minimum distance at which two stimuli (2 simultaneous touches) can be distinguished
differ distances across body

Question 8

absolute threshold

Answer 8

minimum amount of stimulation necessary for a person to detect a stimulus 50% of the time

Question 9

just noticeable difference (JND)

Answer 9

smallest detectable difference between 2 stimuli
minimum change of stimulus that can be correctly judges as different from a reference stimulus

Question 10

how to measure a threshold

Answer 10

psychophysical methods:
- methods of constant stimuli
- method of limits
- method of adjustment

Question 11

method of constant stimuli

Answer 11

presents many stimulus intensities one at a time in random order

Question 12

method of limits

Answer 12

stimulus changes systematically in intensity across trials
stimulus change until listener fails to detect stimuli (YES or NO)
can start at low or high intensity
estimate of threshold made from average from where change occurs

Question 13

method of adjustment

Answer 13

like method of limits but partivipant changes levels themselves

Question 14

webbers law

Answer 14

principle describing the relationship between stimulus and resulting sensation that says JND is a constant fraction of the comparison stimulus (10%)
therefore larger stimulus have bigger JND than small stimulus

Question 15

blackbox problem

Answer 15

• can precisely control physical stimulis (input)
• can precisely measure the experience ( subjective perception)
• but mechanisms and processes in brain cannot be observed

Question 16

sensory firing

Answer 16

Neuronal Firing: The Action Potential
* Neurons fire in an all-or-none fashion for each spike, and the number of spikes per second indicates how excited the neuron is.
* Each action potential starts near the cell body of a neuron and propagates down the axon towards the axon terminal.
* Electrochemical process involving Na+ and K+ ions moving in and
out of the neuron
* Entire populations of neurons work in concert to process information.
* It isn’t clear where a threshold is in an action potential
* But we can learn a lot about networks and specialisation

Question 17

sensory neuroscience (populations)

Answer 17

Modern/non-invasive brain imaging technologies:
– Electroencephalography (EEG)
– Event-related potential (ERP)
- Blood oxugen level dependant signals (BOLD)
- magnetic resonance imaging (MRI)

Question 18

electroceencephalography

Answer 18

A technique that, using many
electrodes on the scalp, measures electrical activity from populations of many neurons in the brain

Question 19

Blood oxygen level-dependant signal

Answer 19

The ratio of oxygenated to
deoxygenated hemoglobin that permits the localization of brain neurons
that are most involved in a task.

Question 20

Event-related potential

Answer 20

A measure of electrical activity from a subpopulation of neurons in response to particular stimuli that requires averaging many EEG recordings

Question 21

magnetic resonance imaging

Answer 21

An imaging technology that uses the responses of atoms to strong magnetic fields to form images of structures like the brain