Mental Imagery Flashcards
(21 cards)
definition of mental imagery:
“Visual mental imagery is a set of representations
that gives rise to the experience of viewing a
stimulus in the absence of appropriate sensory
input” (Kosslyn, 2005).
how did it first come about?
came from experiments
showing that, e.g., memory for pictures and
‘concrete’ words is better than abstract
words (Pavio & Csapo, 1969).
what is the great debate?
Occurred between 1973-2003. The “Kosslyn-Pylyshyn
debate”. The “mental imagery debate”
- mental scanning experiment #
what waa kosslyn, ball and resier (1978) study?
Ps first memorized this map.
Asked to imagine the map and
were given the name of an object
to focus on (e.g., “Beach”).
They then heard the name of
another object (e.g., “well”) and
told to scan their image for that
object.
and pressed button when they found it.
what was kosslyn’s view?
Images have spatial structure
what is the pictorial theory?
An image is retrieved from Long term memory
and sits there in an objective manner.
The observer then uses their visual system to “look
at” the image. They can read-off information.
Images, “once formed, can be
operated upon in various ways”
Images have intrinsic optical and
geometric properties, i.e., have
spatial structure.
whata bout plyshlyn’s view?
published the descriptive theory
It looks like images have spatial
structure. They do not. It looks
like we scan images but this is
an illusion.
We know what it is like to, for
instance, look at a map or look
at the front of our house.
We simulate that experience when generating
an image. Results are not due to any intrinsic
property of the image.
image does not really exist.
what was plylshyn’s view of map scanning?
Pylyshyn (1981) noted that the Kosslyn et al.
(1978) study emphasised scanning, i.e., a
movement of attention across the image.
Pylyshyn (2002) described an experiment in
which no emphasis was placed on scanning.
Ps asked to imagine a light
turned on at a cued object (e.g.,
“Ship”) then a light turned on at
different object (e.g., ”Church”).
Results: No distance effect.
Concluded that the Kosslyn results are not due
to the intrinsic nature of images
what would the null hypothesis be?
Images do not sit there objectively. If they did,
they would adhere better to the laws of nature.
They would not be so malleable.
“You can imagine things being
pretty much any size, color, or
shape that you choose…..You can
imagine all sorts of physically
impossible things”.
what are the issues of representation?
The internal representation itself
is ‘pictorial’ or ‘depictive’.
The representation has distance and space
what did daniel dennett say?
When singing happy
birthday to a relative
over a landline,
information travels
down the wire. But,
that information does
not form the words
“Happy Birthday” as
seen from above.
(Paraphrased from
Dennett, 2002)
what is the homunculus requirement?
In cognitive science the
notion of a homunculus
is used to illustrate how
the brain does not
operate.
e.g., visual perception
what did rene descartes say?
What is in our head when we perceive an
object “bears some resemblance to the
objects from which it proceeds”.
who said, ‘reasoning is based on your knowledge not imagery’.
Pylyshyn
what is mental rotation?
RT task to indicate whether a test object (right)
matched a sample object (left).
Results showed a strong linear relationship
between the degree of angular separation
between the two objects and RT
what did Pylyshyn’s predict?
that RTs should be relatively short at 180 degrees rotation - as symbolic representation of rotated images should be easier to process at 180 degrees - the coding is just reversed.
who studied the equivalence of imagery and perception?
Podgorny & Shepard (1978)
what is the oblique effect?
The threshold for seeing a vertical peripheral
grating is lower than for a diagonal grating.
Kosslyn et al. found the same effect for mental
images of gratings. Not easily explained by the
Pylyshyn simulation account.
If imagery and perception
are equivalent, one should
expect smooth pursuit for an
imagined movement
People can track objects in
the absence of visual input
(Barnes, 2008, review).
This does not occur for imagined motion
Can we reinterpret images?
“In other words, the appearance
of a memory image precedes its
interpretation by the usual
perceptual processes”.
