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Context Localizer
Below, please find links to the stimuli we have used in our research on contextual processing. These stimuli can be used to localize the cortical areas underlying contextual associations; for further details, consult 'Procedure', below. We provide these resources to the academic community for non-profit research purposes. Stimuli and procedure are based on those used in the experiments reported in Bar & Aminoff (2003). Please cite this paper if you use these stimuli or methods in your own research. For comments and suggestions please contact Moshe Bar at bar@nmr.mgh.harvard.edu.
Objects that are strongly 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).
We recommend using a block design with alternating blocks of strong and weak contextual stimuli, interspersed with 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.
Bar, M, & Aminoff, E. (2003). Cortical analysis of visual context. Neuron, 38, 347-358.
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