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Context Localizer
Stimuli
Please find below links to the stimuli we have used in our context experiments. They are color photographs of individual objects on a grey background. Each link is a .zip archive folder of the stimuli that can be unzipped using StuffIt Expander. We provide these sets of stimuli to the academic community for use for non-profit research purposes. Stimuli have been used in, or have been based on the stimuli used in the experiments reported in Bar, M, & Aminoff, E. (2003). Cortical analysis of visual context. Neuron, 38, 347-358. Please cite this paper when using the stimuli. For comments and suggestions please contact Moshe Bar at bar@nmr.mgh.harvard.edu.
Two sets of stimuli:
Objects that are strongly associated with a context. These objects are associated with a context. For example, a roulette wheel is strongly associated with a casino and gambling, and a golf cart is strongly associated with playing golf and a golf course.
Objects that are weakly associated with many contexts, or have no contextual association. For example, a step stool and a piece of candy have no strong associations with any context or place.
Other than the difference in number of contextual associations (i.e., Strong vs, Weak) the stimuli were equalized in other dimensions, as elaborated in (Bar & Aminoff, 2003).
Procedure
Using these stimuli the cortical areas processing contextual associations can be localized. We recommend using a block design alternating blocks of strong contextual stimuli with blocks of weak contextual stimuli with interleaved fixation blocks. Each block should contain about 10 stimuli. We recommend presenting each stimuli for 1700ms with a 300ms ISI.The participant's task is to judge whether the item shown is smaller than a shoebox.
Here is a typical sample of results. This is a random effects group average of eleven subjects using a gamma fit analysis and a smoothing kernel of 7mm.
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