Rotação Mental
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Overview
Fonte: Laboratório de Jonathan Flombaum – Universidade Johns Hopkins
Imagens mentais visuais referem-se à capacidade de evocar imagens nos olhos de alguém. Isso permite que as pessoas processem material visual acima e além das restrições de um ponto de vista atual; por exemplo, uma pessoa poderia imaginar, usando o olho de sua mente, como algo poderia parecer em uma cor diferente, ou como seria se fosse feito de um material diferente ou girado e visto de uma perspectiva diferente. As imagens mentais parecem apoiar comportamentos humanos importantes em muitos contextos. Por exemplo, as pessoas relatam visualizar rotas e mapas ao planejar uma rota ou dar direções. Eles relatam movimentos visualizadores, como balançar um bastão, para se preparar para uma ação real. Eles também relatam a rotação mental de objetos a fim de considerar como um objeto pode caber em um recipiente ou limpar uma barreira.
Este vídeo demonstra como usar o procedimento de rotação mental para investigar imagens mentais visuais.
Procedure
Results
A common way to graph the results is to plot the response time for each character as a function of the rotation of the character (and its mirror image; Figure 6).
Figure 6. Results from the mental rotation task. Response times are plotted for each of the characters as a function of the amount of rotation in a given trial. Generally, response times are longer the more a character is rotated from its canonical orientation, suggesting that brain mechanisms simulate physical transformations.
One of the most interesting common results associated with mental rotation tasks is that the amount of time it takes to produce a response is proportional to the degree of rotation distinguishing the target character and its rotated pair. In other words, the time it takes to rotate an object mentally seems proportional to the time it would take to actually rotate physical objects in order to place them at the same orientation. This suggests that mental rotation relies on mechanisms that really try to simulate physical space in the brain, even though no pieces of the brain rotate.
Applications and Summary
One of the main practical applications for mental rotation tasks is to identify people who are especially good at visual thinking about physical spaces. Think about the skills it takes to be a good architect, mechanical engineer, an expert carpenter, or welder. Some people are really good at using mental imagery to guide their actions, and some people are not very good at all, reporting that they don’t even really see pictures in their mind’s eye the way most people do. The mental rotation test is a good way to identify exceptionally good and exceptionally bad visualizers in order to help people find the best uses of their abilities.
Mental rotation has also been an important part of neuroscience research aimed at understanding the parts of the occipital and parietal lobes involved in human vision. One of the most surprising findings is that when people mentally rotate objects without looking at them, there is an enormous amount of brain activity in visual cortex and brain areas generally thought to be involved in seeing. In other words, the brain systems used to actually see visual stimuli are also used to imagine visual stimuli.
Transcript
Individuals must rely on visual mental imagery—the ability to conjure images in one’s mind’s eye—to accurately perceive the world and guide actions.
For example, mental imagery is used to visualize a route when planning directions to particular location, or what a house might look like if it were remodeled.
Experimental psychologists can measure a person’s visual mental imagery through the use of a mental rotation paradigm, which involves identifying rotated versions of familiar characters and distinguishing them from rotated versions of their mirror images.
Using the mental rotation procedure, this video will demonstrate how to design stimuli and conduct an experiment, as well as how to analyze and interpret results investigating visual mental imagery.
In this experiment, participants are presented with stimuli and asked to distinguish whether subsequent stimuli are rotations of the original item or of its mirror image.
In this case, the task stimuli consist of letters, such as R and g, as well as numbers, like 4 and 7, all printed in Helvetica Light font.
Two versions of the letters and numbers are produced: the original and a flipped, mirror image. The characters are then manipulated, such that each one is rotated by an increasing increment of 15°, starting at 0° and ending at 180°.
During each trial, participants are presented with one of the four manipulated characters and then asked to decide from two possible choices which one is the rotated version of the original item as quickly and accurately as possible.
Thus, the dependent variable is response time—how long it takes for the participant to make a response.
It is hypothesized that response times will be faster for characters that have little rotation, compared to those that are rotated the most. In other words, the response times are longer the more a character is rotated from its canonical orientation.
To begin the experiment, gather stimuli sheets that have been created for each individual trial. For each trial, note that one of the four non-mirror images is printed at the top, and the two choices are located on the bottom of the page.
Number the back of each page from 1–52, which is called the ‘number tag.’ To randomize the order, shuffle the test pages.
To more easily associate the results with the content of each trial, create a response sheet that includes the trial number, number tag in the order of presentation, response given, and response time.
As the last preparation step, gather a stopwatch and an assistant.
When the participant arrives, explain the instructions to them using a demo page. Note that one of the characters, its mirror image, and a couple of examples of the character at one of the rotations is shown.
Next, place the test pages facedown between the experimenter and the participant.
During each trial, once the assistant starts the timer and says, “Go,” flip over a page for the participant.
When the participant reports a response, stop the timer. Then, record the response time and the answer on the response sheet. Repeat this procedure for all 52 trials.
Once the experiment is complete, create a digital copy of the response sheet, including the number tags in numerical order, responses given, response times, and correct answers.
Mark whether the responses given were correct by entering a 1 in the ‘Answer Correct?’ column or a 0 if incorrect.
For the correct trials, plot the average response times for each character shown as a function of rotation. Note that the response times increase proportionally with the degree of rotation. These results suggest that the brain simulates the physical transformations.
Now that you are familiar with designing a mental rotation experiment, you can apply this approach to answer specific questions about visual mental imagery.
Practically speaking, people who are especially good at visual thinking about physical spaces can be identified through the mental rotation task. Certain individuals are exceptionally good at using mental imagery to guide their actions—like architects and mechanical engineers.
In addition, researchers use functional magnetic resonance imaging to investigate brain regions involved in mental rotation.
When people mentally rotate objects without looking at them, there is an enormous amount of brain activity in the visual cortex in particular, and in regions such as the parietal lobe—brain areas generally thought to be involved in seeing. In other words, the brain systems used to actually see visual stimuli are also used to imagine visual stimuli.
Finally, researchers examine mental rotation in virtual reality to study how mental imagery is involved in navigating through different spatial environments and obstacles.
You’ve just watched JoVE’s introduction to conducting a mental rotation experiment. Now you should have a good understanding of how to design and conduct the experiment, and finally how to analyze and interpret the results.
Thanks for watching!