Brain imaging research examines processes that underlie decision making

Niq Velez

New evidence gathered from brain scans supports the theory that people use specific memories from multiple regions of their brain when making decisions.

Michael Mack, a postdoctoral researcher in psychology and one of the authors of the study, said two opposing models are used to examine how the brain categorizes information during the decision making process — the exemplar model and the prototype model. His research supports the former. 

The exemplar model defines the process as one which integrates many specific memories, while the prototype model defines the decision making process as one that pulls from a general source of memories, Mack said. Instead of basing decisions upon an abstract mixture of past experiences, exact events and objects provide context.

Mack said participants undertook a controlled, simple categorization task so they could look at the regions of the brain that were activated during the decision-making process. Participants were asked to differentiate between various models of cars as a learning experiment — cars in general share many similarities, so there are certain defining characteristics that must be recalled.

“When you ask someone to differentiate between a Honda Civic and a Volkswagen Bug, only some features matter in making that decision,” Mack said. “We found evidence that people are utilizing specific memories instead of pulling from a general source. You can use these specific memories in a lot of different kinds of decisions.”

Psychology junior Isabel Glass said that the majority of research in the field pertains to the prototype model, but she feels the exemplar model is more accurate.

“In my personal experience, I have certain memories of my life that really stand out, that you can relate to various situations,” Glass said. 

Chemistry senior Michael Ortiz said it is possible to have a rough understanding of brain processes through neural imaging techniques, but the brain is far too complex to be predictable.

“We can obviously see what parts of the brain are active, and how they correlate to other parts of the brain when they’re active at the same time, but I think that how those things act out in the behavioral sense depends on the person,” Ortiz said. 

Mack said this study was based on brain scans that were collected after the learning process had already occurred, but technological advances could allow researchers to study the brain as it categorizes new information.

“In this research project people were trained to make these judgments, and then their brains were scanned afterwards,” Mack said. “We only looked at the post-learning process, but we’re heading towards looking at the brain during the learning process.”