Close your eyes and imagine a vase with flowers.
Do you see a clear visual image?
Maybe it's a blue vase with red roses.
Or maybe it's crystal clear with yellow wild flowers
Our ability to mentally visualize or conjure up mental images in our head
is somewhat different from visual perception.
That's when our brains are creating an image of something that physically in front of our eyes.
Mental imagery, on the other hand, is when
our brain generates a visual representation of something that is not
physically there.
Visual perception and visual mental imagery might share
underlying common brain mechanisms, but they're not identical processes.
This is because there are people with normal visual perception but don't actually see
mental images when they think about something.
Basically, I have a "blind mind's eye"
Psychologists have debated about whether or not
thoughts can exist without images, such as those psychologists who subscribe to
the Wurtzburg School of Imageless Thought.
This phenomenon of people reporting that they don't have mental images
has also been recorded by Sir Francis Galton in the 1880s.
Recently, it has attracted attention due
to a new name: aphantasia.
This term was coined by Professor Zeman at the
University of Exeter.
"Phantasia" is the ancient philosopher Aristotle's name for
the mind's eye. Aphantasia is thus "lack of a mind's eye".
Many people might rely almost exclusively on mental images to process information
day to day, so they might not be able to imagine how to survive without them.
So how can science tell if someone has a picture in their mind when they're thinking?
First there are self reports, such as the "vividness of mental imagery" questionnaire.
There are also cognitive tests, such as
this mental rotation task.
These tasks use a person's reaction time and accuracy
to give us clues as to what kind of mental strategies they're using
to solve the visual or spatial puzzle.
Ultimately, these cognitive tasks
combined with brain imaging such as functional magnetic resonance imaging
will give us more neuroscientific insights into why our inner perceptions
can be so different.
Dr. Zeman and other researchers published a very interesting
case study of a man who used to have mental imagery but then lost it after a surgery.
They found that this man used his posterior visual networks less than
subjects who could produce mental images when they were all asked to imagine the
faces of famous people when provided with their names.
Instead, this person activated more of his frontal cortical networks,
suggesting that he was using a non visual ways to solve the task.
For people like me who are non -imagers at birth,
it might seem crazy to think that we don't perceive the world exactly the
same as else.
But it really shouldn't be surprising.
Even though all our brain structures will be similar, our genetics
and past experiences will impact our mental representations as well as our
functional neural networks.
The important thing to remember is that just because
we don't have pictures when we imagine, it doesn't mean we don't have imaginations at all!
There are people with aphantasia who are writers and artists
and musicians, and much much more!
Although you might feel alone in having
a different kind of inner world, there are people all around the globe
that identify as having aphantasia.
If you'd like to meet more of them, please join the Aphantasia Facebook group,
or reach out to participate in mental imagery studies.
There's still a lot to learn about mental imagery,
and you can help us learn more!