Wednesday, August 24, 2016

The possible influences of mental images on a child's functioning in school and out of it


This is a fourth (and last?) of a series of posts on mental imagery. 

People don't always like to see movies based on books they have read.  They are afraid that the movie would look different than the way they saw things in their mind's eye.  Sometimes they express disappointment at a character's  appearance:  "He is not supposed to look this way!"  When reading we form mental images of the characters and the surrounding.  We don't only "know" how things look, by the descriptions in the book.  We "see" them in our mind's eye. 

When reading, we do not only form visual images but auditory images as well.  A few years ago my daughter burst out laughing when reading a book (silently).  It turned out that she read the question "What happened?" as a shout, and then saw that the next words were "he whispered".  At first, the character was shouting in her mind's ear. 

Does it mean that individual differences in the ability to form mental images affect their reading comprehension?  Does a person who forms mental images which are less vivid or precise understand the scene less well?  Would a person who finds it hard to control the mental image of a scene (for example, to see it from different angles, to update the image when new information unfolds) understand it less well?

When we remember events from our past, we may recall some of them in great detail.  For instance, when we recall an event that took place by the beach, we see with our mind's eye the specific beach where the event happened, and the people and objects that participated in it.  We can form auditory images of the seagull cries, olfactory images of the salty smell of the sea, and these mental images may help us to remember what we thought and felt during the event.  Mental images are probably part of the way we store and retrieve information in memory.

As we've seen in the first post, mental images are processed in brain areas devoted to perception.   For example, when a person forms a visual image he activates brain areas that are activated during visual perception.  Furthermore: brain areas related to visual perception are activated during retrieval from episodic memory (memory for our life events).  Thus damage to brain areas that support visual perception leads both to visual imagery loss and to episodic memory loss.  According to Dr. Zeman, people with permanent attenuation in the ability to form visual images are at a greater risk for poor memory for their life events.  The opposite also seems to be true:  people with extremely poor episodic memory report having poor ability to form visual images.

What about thinking about the future and decision making?  The ability to remember the past and to think about the future are linked.  Episodic memory and the ability to project ourselves into the future (to think about the future with ourselves in it) appear at a similar period of development – around age four.  People who, following brain damage, are not able to remember their personal past usually have difficulty imagining possible future experiences.  Thus it's possible that people who have difficulty forming mental images also have difficulty imagining the future and projecting themselves into the future. 

The ability to imagine the future affects our ability to make decisions.  Prof.  Bence Nanay argues that we make decisions by forming a mental image of each possible alternative and placing ourselves in it.  For example, if a child has to choose an afterschool activity, he forms mental images of himself in each activity.  These images help him to make the decision.

Ernest argued in 1977 that individual differences in the ability to form mental images can significantly influence a range of cognitive functions such as learning, memory, perception and problem solving. 

Yet no correlation was found between the ability to form mental images (as reported by questionnaires) and people's level of performance on tasks that allegedly require imaging, for example, mental rotation, visual memory and visual recognition.  No correlation was found between the reported vividness of mental images and people's performance in terms of speed or precision on visual spatial tasks and on problem solving tasks that seem to require the formation of mental images. 

Galton wrote in the 19th century:  ‘Men who declare themselves entirely deficient in the power of seeing mental pictures can nevertheless … become painters of the rank of Royal Academicians’

How do we explain this?  Here are several possibilities:

A.  People can perform tasks that allegedly require mental imagery in other ways, without the formation of mental imagery.  These ways may be less effective, but they nevertheless enable them to perform the tasks.

B.  Tests that supposedly require the formation of mental images do not resemble everyday functioning.  The manipulations of imagery required in these tasks is different in kind and complexity from manipulations of mental images in everyday life.

C.  People who report having no mental imagery do form images but are not aware of it.

D.  Questionnaires that measure the quality of mental imagery measure different phenomena than is measured by tests that allegedly require the formation of mental images.

E.  Questionnaires that were used in some of the studies did not differentiate between different kinds of mental images.

It's possible to identify two kinds of mental imagery:  mental imagery of objects and mental imagery of spatial relations.  The ability to form object imagery is the ability to image the form of objects, their color, texture, scent and other details.  This is the ability to form a mental image of a rose in its full vividness and scent.  The ability to form spatial relations imagery is the ability to form an image of the relative placement of objects in space, the ability to mentally move the objects in relation to each other and to image changes in objects.  This is, for instance, the ability to image the look of the whole garden, with shrub roses, trees, benches and so on.  This is the ability to image where the shrub roses are placed relative to other objects in the garden, and the ability to image the wind blowing the rose petals.  Maybe these different kinds of images affect performance on tests that require the formation of mental images in different ways. 

Sixth grade children were given math word problems and then were asked to describe the way they solved them.  For instance, they solved the following problem:  "At each of the two ends of a straight path, a man planted a tree, and then every 5 meters along the path he planted another tree. The length of the path is 15 meters. How many trees were planted?"

Children who used spatial imagery used gestures in their descriptions that showed the spatial relations between objects in the problem, or reported having spatial images of the relations in the problem.  For example:  "I had a [mental] picture of the path, not the trees, and it had something 5 meters along, not trees, just something."  Children who used spatial imagery also created drawings of the problem that depicted the relations between objects.

Children who used object imagery reported images of objects or people mentioned in the problems, and not the relations between them.  For instance:  "I saw the man planting a tree".

Children who used spatial mental imagery did better on the word problems than children who used object imagery.  The researchers argue that forming object images turns attention away from the relations between objects in the problem.

In another study with adults, it was found that scientists and engineers excel in spatial imagery and prefer spatial strategies, whereas visual artists excel in object imagery and prefer object-based strategies.

To sum up, mental images assist in everyday functioning.  People differ in their ability to have mental images and in the kinds of mental images they form.  Different kinds of mental images can help to perform different kinds of tasks.  People who can't form mental images can succeed in the same tasks, probably by using other strategies.

Zeman, A., Dewar, M., & Della Sala, S. (2015). Lives without imagery–Congenital aphantasia. Cortex, 3.

Sheldon, S., Amaral, R., & Levine, B. (2016). Individual differences in visual imagery determine how event information is remembered. Memory, 1-10.

Hegarty, M., & Kozhevnikov, M. (1999). Types of visual–spatial representations and mathematical problem solving. Journal of educational psychology, 91(4), 684.http://www.nmr.mgh.harvard.edu/mkozhevnlab/wp-content/uploads/pdfs/types_visual1999.pdf

Kozhevnikov, M., Kosslyn, S., and Shepard, J. Spatial versus object visualizers:  a new characterization of visual cognitive style. Memory and Cognition 2005, 33(4), 710-726.  http://nmr.mgh.harvard.edu/mkozhevnlab/wp-content/uploads/pdfs/spatial_versus2005.pdf





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