For psychology, sensation and perception is important because it is how we see
and understand the world around us. This affects how we behave in response to
our environment, and how we understand and interact with everything in our
world. This is also a major topic for neuroscience and artificial intelligence
because most of our brain is involved in processing sensory information.
The senses → we have five senses: sight, sound, taste, smell and touch. Each
of these has a sensory organ associated with it. Within these sensory organs,
,there are specific sensory receptor neurons that interact with something
physical in the outside world.
Sense Sensory organ
Vision (sight) Eyes (retina)
Hearing (audition) Ears (Cochlea)
Taste (gustation) Tongue (taste buds)
Smell (olfaction) Nose (olfactory epithelium)
Touch (somatosensorial) Skin etc. (many)
Balance (vestibular) Vestibular labyrinths
Our sense of touch is not a single sense. Much relies on the skin, there are
many distinct sensory receptors involved, each producing distinct sensations. For
example: light touch, deep touch, stretch, heat, cold or pain.
A single type of sensory receptor’s activity can be analyzed in multiple
ways, so that there are multiple parts within each sense.
For example, vision → all of these different aspects begin in the same place, the
eye, and share early processing stages. But then the are separated into different
functions performed by different pathways.
- The eye and early visual pathways
o Form (shape)
o Motion
o Colour
o Depth and distance
o Cognitive influences: attention and awareness
Similarly, hearing all starts with the ear, but then has separate analyses for the
sounds location and frequency structure.
Why so much vision?
- Vision is the primary sense in humans
o Almost every action we make is guided by vision
- We do a lot of analysis of vision
o Object recognition
o Form and colour
o Space and motion
o Location, motion, distance and depth
As a result, a huge proportion of our brain is devoted to visual processing.
Conversely, only small specific brain areas are involved in human touch
processing and auditory processing. Very small areas are involved in taste, smell
and vestibular processing. It is also easy to study.
,Dualism or monism?
Dualism → humans have mind or spirit separate from the physical body
Monism → the mind is an aspect of the body, held in the brain and nervous
system. This course will take this view.
Sensation and perception
Sensation → a translation of the external physical environment into a pattern of
neural activity (by a sensory organ).
Perception: analysis of this neural activity to understand the environment and
guide behavior.
Sensation and perception reflect interactions between our sensory organs and
physical properties of the world, so they are:
- Dependent on physical properties of the world
- Limited by the physical properties of our sensors
We may feel that we perceive the world as it truly is. But in fact we don’t
perceive the world accurately at all. Understanding the physical and neural basis
of perception often reveals why we perceive things as we do.
Dependence on physical properties of the world
Visible light has a short wavelength and does not reflect from most surfaces, so
it does not travel around corners.
However, sound has a longer wavelength and reflects more easily, so we can
generally hear around corners fairly well: we can hear this car around a corner,
but can only see around the corner with a mirror.
Limitations of the physical properties of our sensors
The human eye is only sensitive to a short range of wavelengths of light, part of
a much larger electromagnetic spectrum. Honeybees can see ultraviolet
wavelengths which humans can’t, changing the appearance of a flower.
Sensation and perception have evolved to help us survive and reproduce, so
they are:
- Optimized for useful representation of the environment
- Influenced by interpretation: context and experience
- Dependent on limited resources of attention and awareness (we can
sometimes receive more input than we can process)
How to study perception?
, - A translation of the physical environment into a pattern of neural activity
can be used by our brain to guide behavior
- So to study perception experimentally:
o Change the physical environment of a human or animal (sensory
stimulus)
o Measure the resulting behavior or
o Measure the resulting change in neural activity
Psychological approach (Weber and Fechner):
- Quantitative measurements of behavior resulting from perception
- The scientific study of the relation between stimulus and sensation
- Best understood as testing whether subjects perceive a difference between
two stimuli
- We can just notice the extra light of one candle when added to three
candles, but not when added to the light of six candles. Against six
candles, we need two extra candles.
- So, if we determine the just noticeable difference, the change in the
environment that we can only just perceive, its size depends on the
stimulus that is being compared.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller pdamman. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.85. You're not tied to anything after your purchase.