Chapter 6—Sensation and Perception
Detection of physical energy and its interpretation
How we sense, generally:
o Sense receptor ,
Picks up physical energy. it could be a sound wave, a light
wave, or a smell.
o Sensory neuron/nerves,
Send the information to the brain for interpretation
o Doctrine of specific nerve energies
Says we have different anatomy for different sensations.
Anatomical coding: thalamus sends the information along
o Sensory Crossover (synesthesia)
Too many connections in your brain and things collide.
One sense evokes another. (e.g. 7 = red)
Too many connections have haven’t been pruned.
But can’t explain differences within a sensation
o Functional coding
When some cells fire, and some don’t.
It is the pattern of firing that provides the distinctions.
Anatomical coding can’t explain the differences within a
sensation, but functional coding can.
Sensory Adaptation (getting used to a sensation) After
prolonged exposure to a sensation, neurons fire less frequently and
sensitivity goes down.
Intensity Your sensitivity is not going to decrease for strong
smells, temperature, and pain
Vision Location of the image on your retina is every-changing
so neurons don’t fatigue
1 Selective Attention (focus of attention of some aspects and
blocking out of others)
o Inattentional blindness is a result of selective attention (lack of
Absolute threshold: smallest amount of energy that can detect 50% of
Just noticeable difference: smallest detectable difference between two
Signal detection theory (signal detection involves both sensation and
Argues that how much we sense is not
only about how much physical energy is
there, but also by their motivation and
People who get hits or false
alarms: yes men
Yes men= people who say that
something is there, when it really isn’t.
Do you see it? And you reply
yes, it is a hit.
Do you see it? And you
reply yes but there isn’t anything there
but they think they see it, it is a false
Nay-Sayers: people who say no
because they don’t see anything.
o Uses a formula to account for people’s motivation to accurately judge
Sensation: light waves
Perception: hue (colour/length of the light wave), brightness (the height
of the wave), saturation (the pureness of colour).
How we see:
1. The presentation of the light wave goes through the CORNEA.
a. It is there to protect the rest of the eye, and the light enters through it.
2. The second place that light goes through id the PUPIL and the IRIS
a. Iris: the colour of the eye
b. The black dot in the middle that contracts or dilates dependingon how much light is in the