Mental visual imagery – can a language encoded object generate depictive imagery? Igor Bascandziev Harvard Graduate School of Education

Presentation overview Introduction An overview of the debate What has been found so far Open questions and motivation Experiment proposal (research question, design, tasks, anticipated findings) Limitations

Introduction History (philosophy, cognitive psychology, advent of neuroimaging studies) The debate – is the visual mental imagery different from the rest of general reasoning? Zenon Pylyshyn – “same forms of representation as are involved in general reasoning” Stephen Kosslyn – the mental imagery is not describing the objects, but it depicts objects

The depictive nature The early visual area is topographic, depictive, and functionally activated during perception If the very same region is functionally engaged during visual imagery, then that should serve as evidence that the visual mental imagery is depictive

What has been found Many studies showed activations in the early visual area during mental imagery But many studies did not replicate this finding It’s more complicated than just having any task of mental imagery

What has been found – short summary Activation if object imagery, deactivation if spatial imagery More likely to find activation if - the task asks for high resolution object detail - if there is an image suppression - if the imaging is conducted with a powerful fMRI (e.g. 4T)

What has been found Neuropsychological evidence that damage in the early visual cortex influences mental imagery TMS studies showing that temporary disruptions of the early visual cortex cause deficit in the ability to generate mental image Behavioral studies combined with imaging studies – negative correlation between activation and response time

Open questions and implications If we assume that the visual mental imagery is depictive, then interesting question would be: Whether there is a difference between objects encoded through perception and objects encoded through language?

Open questions and implications It will show whether an object encoded only through language hinges upon the depictive visual imagery It will suggest that the depictive visual imagery could be strongly influenced by a top down processes

Experiment proposal - RQ Is there a difference between the mental imagery of an object encoded through perception and the mental imagery of an object encoded through language?

Experiment proposal – design and tasks Target sample size n=10 Event related design Before the scanning Test to check subjects’ knowledge about animals Learning period – each subject will learn about visual characteristics of non-existing made-up animals. At the end of the learning, test to check subjects’ knowledge of the made-up animals

Experiment proposal – design and tasks Two conditions (real animal and made-up animal) The procedure will be similar to the one in Klein et al. (2000). Source: Klein et al. (2000)

Experiment proposal – anticipated findings There will be activation of the early visual area in both conditions The familiarity with the object will be positively correlated with activations The familiarity with the object will be positively correlated with the number of correct answers and negatively correlated with the response times

Experiment proposal – anticipated findings As an example, I present Klein et al. (2000) finding

Limitations Difficult to control the familiarity factor Are the objects really encoded by language, or the subjects just combine previously perceived parts of animals

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