Subtraction Paradigm
Subtraction Paradigm - Related Videos
09:43
Measuring Reaction Time and Donders' Method of Subtraction
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2023
Source: Laboratory of Jonathan Flombaum—Johns Hopkins University The ambition of experimental psychology is to characterize the mental events that support the human ability to solve problems, perceive the world, and turn thoughts into words and sentences. But people cannot see or feel those mental events; they cannot be weighed, combined in test tubes, or grown in a dish. Wanting to study mental life, nonetheless, Franciscus Donders, a Dutch ophthalmologist in the early 1800s, came up with a...
09:15
Creating the Minimal Group Paradigm
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2023
Source: Julian Wills & Jay Van Bavel—New York University The study of intergroup relations, such as prejudice, conflict, and discrimination, has always been a central topic in social psychology. Does discrimination stem from competition with other groups, a history of conflict, or derogatory stereotypes? Despite an abundance of real-world examples, the ingredients that lead to intergroup discrimination are often unclear. To help solve this problem, a group of psychologists created "minimal...
14:56
An Experimental Paradigm for the Prediction of Post-Operative Pain (PPOP)
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Cited by 107 •
2010
Diffuse noxious inhibitory control, temporal summation and wound hyperalgesia testing are demonstrated in the obstetric patient. These tests evaluate inhibitory and excitatory mechanisms of pain processing and are here utilized to evaluate endogenous analgesia at different time-points during pregnancy and the peripartum period to help reveal individual s risk for persistent pain.
01:22
Detection of Internal Carotid Artery Narrowing Using Digital Subtraction Angiography
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2025
Position a human patient with internal carotid stenosis, a condition characterized by narrowing of the internal carotid artery, on the imaging table for digital subtraction angiography (DSA). Insert an angiocatheter into the common carotid artery at the fourth cervical vertebra level. Capture a pre-contrast X-ray image to record background structures like bones and soft tissues using X-ray irradiation. Administer an iodine-based contrast medium into the carotid artery. The contrast medium...
09:40
Novel Sequence Discovery by Subtractive Genomics
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Cited by 8 •
2019
The purpose of this protocol is to use a combination of computational and bench research to find novel sequences that cannot be easily separated from a co-purifying sequence, which may be only partially known.
FAQs
The subtraction paradigm depends on an additive-process assumption: the mental components in the full and control tasks must combine independently. If they interact, the measured difference may reflect an interaction between processes rather than the target process alone. This assumption therefore determines how confidently researchers can interpret a subtraction as a specific psychological operation.
Carefully matched conditions reduce the chance that an observed difference reflects unrelated task demands. The control condition should preserve the relevant features of the comparison task while omitting the process under study, so changes in reaction time, accuracy, or neural activity can be linked more directly to that component. Poor matching weakens the inference.
Each measure answers a somewhat different question. A reaction-time difference provides an estimate of the time associated with the added process, whereas accuracy differences show how performance changes when that process is included. In cognitive neuroscience, differences in neural activity offer a corresponding way to examine process-related brain responses, subject to the comparison design.
Researchers can compare neural activity in a condition containing a psychological process with activity in a matched condition that omits it. The resulting difference may indicate activity associated with that process, but it is not automatically a direct readout of it. Interpretation depends on control quality and the assumption that component processes combine independently.
Researchers first specify the mental process of interest, then construct a task that includes it and a carefully matched control task that omits it. They measure performance or neural activity in both conditions and calculate the difference. That contrast becomes the estimate used to evaluate the target process.
Within psychology, the method has been applied to questions about attention, perception, memory, and decision-making. Its value is comparative: researchers can ask how adding a particular mental component changes task performance or neural activity relative to a related condition. This makes it relevant to both behavioral experiments and cognitive-neuroscience investigations.