In this video, we will have a look at perception
and cognition and how our bodies are actively involved
in perceiving and understanding our environment.
Consider what happens when you hear a song.
An obvious chain of events is sound waves
hitting your eardrum, causing a chain of vibrations
in your middle and inner ear, which
is picked up by a large number of nerve cells
and sent as electrical signals to your brain.
We recognise these signals as various instruments,
with rhythm, pitch, harmonies, and lyrics.
And this cocktail of sound has the power
to put you in a certain emotional state.
In this video, we will look at some of the processes involved
in the example that I just gave and also
detail out what is missing in such an explanation of how we
understand the world around us.
When you're listening to music, are you only listening?
In fact, perceiving is a more appropriate term
than listening.
Even the most attentive audience of classical music
does not only listen when perceiving music.
In addition to auditory input, visual input
plays an important role.
And movement, either as physical body movement
or just sensations of movement, is
an important part of music perception,
as well as emotional responses, a sort
of attunement to the emotions expressed in the music.
So knowing that music perception involves active processes
like movement or emotional attunement,
is your perception of music determined by the music itself
or by your preconception of the music?
For a long time, psychologists have
debated whether perception is a bottom-up
or a top-down process.
Bottom-up in this sense refers to a data-driven process
where perception starts with the stimulus itself,
from vibrations in the air to the auditory cortex, where
the analysis of a stimulus gets more and more complex.
Top-down refers to hypothesising about stimuli
based on previous experiences and memories.
Neither of the two extremes is capable of explaining
all perceptual phenomena alone, and most psychologists today
agree that perception involves both bottom-up processing
and top-down processing.
In the field of embodied cognition,
cognitive processes are explained
as being inseparable from the body.
The perceiver is not only a passive receiver of information
which is being processed and understood in the brain alone.
Rather, the perceiver is active and interacts
with the environment.
And several researchers in the last part of the 20th century
contributed with theories and findings that support this.
James Gibson introduced the term affordances,
which he defined as action possibilities.
In Gibson's explanation of what he
called the ecological approach to perception,
actions are integral to perception.
The way that a person perceives something cannot be separated
from the person nor the actions it affords to the person.
For instance, a table might afford the action leaning
on to an adult. But a small child
might be unable to reach the table,
and so the table is not perceived in the same manner.
The table might rather afford the action standing
under to the child.
Another theory that supports the idea of an active perceiver
was George Lakoff and Mark Johnson's work on metaphors.
In the book Metaphors We Live By, they
argue that experiences of the world
are heavily structured around metaphors,
and metaphors relating to our own physical and social
experiences in particular.
Alvin Liberman and Ignatius Mattingly
argued that the way we perceive speech
is by means of projecting the perceived sounds
onto our own vocal apparatus.
In other words, we understand words
by mentally mimicking the sound production.
This theory was met by harsh criticism
and is still being criticised.
However, it was strengthened by the discovery of mirror neurons
in the early 1990s.
A group of researchers in Parma, Italy,
was studying activity of the premotor cortex
in the brain of macaque monkeys.
Previously, activity had been found in the premotor cortex
whenever a monkey did certain types of planned action,
such as picking up an object.
Incidentally, during a break in the experiments,
the researchers observed activation
in the premotor cortex of the monkey
when the monkey sat stationary watching the experimenter
perform the same action.
In other words, there is motor activity in the brain,
not only when performing an action,
but also when perceiving an action.
The neurons that fired during observation have been labelled
mirror neurons.
Mirror neurons have later been found
to fire also when monkeys hear the sound of an action,
such as the sound of breaking a stick.
And even for pianists, activity has
been found in the premotor cortex
when listening to a piano piece without any overt movement.