Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Bad decisions arise from faulty information, not faulty brain circuits

Making decisions involves a gradual accumulation of facts that support one choice or another. A person choosing a college might weigh factors such as course selection, institutional reputation and the quality of future job prospects.

But if the wrong choice is made, Princeton University researchers have found that it might be the information rather than the brain's decision-making process that is to blame. The researchers report in the journal Science that erroneous decisions tend to arise from errors, or "noise," in the information coming into the brain rather than errors in how the brain accumulates information.

These findings address a fundamental question among neuroscientists about whether bad decisions result from noise in the external information — or sensory input — or because the brain made mistakes when tallying that information. In the example of choosing a college, the question might be whether a person made a poor choice because of misleading or confusing course descriptions, or because the brain failed to remember which college had the best ratings.

Previous measurements of brain neurons have indicated that brain functions are inherently noisy. The Princeton research, however, separated sensory inputs from the internal mental process to show that the former can be noisy while the latter is remarkably reliable, said senior investigator Carlos Brody, a Princeton associate professor of molecular biology and the Princeton Neuroscience Institute (PNI), and a Howard Hughes Medical Institute Investigator.

"To our great surprise, the internal mental process was perfectly noiseless. All of the imperfections came from noise in the sensory processes," Brody said. Brody worked with first author Bingni Brunton, now a postdoctoral research associate in the departments of biology and applied mathematics at the University of Washington; and Matthew Botvinick, a Princeton associate professor of psychology and PNI.

The research subjects — four college-age volunteers and 19 laboratory rats — listened to streams of randomly timed clicks coming into both the left ear and the right ear. After listening to a stream, the subjects had to choose the side from which more clicks originated. The rats had been trained to turn their noses in the direction from which more clicks originated.

The test subjects mostly chose the correct side but occasionally made errors. By comparing various patterns of clicks with the volunteers' responses, researchers found that all of the errors arose when two clicks overlapped, and not from any observable noise in the brain system that tallied the clicks. This was true in experiment after experiment utilizing different click patterns, in humans and rats.

The researchers used the timing of the clicks and the decision-making behavior of the test subjects to create computer models that can be used to indicate what happens in the brain during decision-making. The models provide a clear window into the brain during the "mulling over" period of decision-making, the time when a person is accumulating information but has yet to choose, Brody said.

"Before we conducted this study, we did not have a way of looking at this process without inserting electrodes into the brain," Brody said. "Now thanks to our model, we have an estimation of what is going on at each moment in time during the formation of the decision."

The study suggests that information represented and processed in the brain's neurons must be robust to noise, Brody said. "In other words, the 'neural code' may have a mechanism for inherent error correction," he said.

"The new work from the Brody lab is important for a few reasons," said Anne Churchland, an assistant professor of biological sciences at Cold Spring Harbor Laboratory who studies decision-making and was not involved in the study. "First, the work was very innovative because the researchers were able to study carefully controlled decision-making behavior in rodents. This is surprising in that one might have guessed rodents were incapable of producing stable, reliable decisions that are based on complex sensory stimuli.

"This work exposed some unexpected features of why animals, including humans, sometimes make incorrect decisions," Churchland said. "Specifically, the researchers found that errors are mostly driven by the inability to accurately encode sensory information. Alternative possibilities, which the authors ruled out, included noise associated with holding the stimulus in mind, or memory noise, and noise associated with a bias toward one alternative or the other."

The paper, "Rats and Humans Can Optimally Accumulate Evidence for Decision Making," was published online by Science April 4. The work was funded by the Howard Hughes Medical Institute, Princeton University and National Institutes of Health training grants.

[Images and a Podcast are available at To obtain high-res images, contact Princeton science writer Morgan Kelly, (609) 258-5729,]

Morgan Kelly | EurekAlert!
Further information:

More articles from Health and Medicine:

nachricht Resolving the mystery of preeclampsia
21.10.2016 | Universitätsklinikum Magdeburg

nachricht New potential cancer treatment using microwaves to target deep tumors
12.10.2016 | University of Texas at Arlington

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>