Summary: Researchers have unveiled new insights into a specific brain signal known as “Reward Positivity,” which may bridge the gap between simple pleasure and complex goal-setting. This electrical burst, occurring roughly 200 to 500 milliseconds after a positive outcome, has long been used to study how we learn from surprises. However, a new theoretical review suggests that scientists have often conflated “rewards” (like the taste of sugar) with “goals” (like choosing water to stay healthy).
In individuals with clinical depression, specifically those experiencing anhedonia, this signal is significantly diminished. By refining our understanding of this signal as a marker for higher-order cognitive control rather than just a dopamine response, researchers hope to use it as a non-invasive tool to predict antidepressant success and measure neural health in clinical trials.
Key Facts
- The “Reward Positivity” Signal: A burst of positive voltage that appears shortly after a person receives a reward or confirmation of success (e.g., a “thumbs up” or a dollar).
- The Goal vs. Reward Distinction: While a “reward” triggers lower-level dopaminergic systems, a “goal” involves higher-level cognitive control—the brain’s way of “checking off a list” based on decided importance.
- Depression Biomarker: The Reward Positivity signal is consistently smaller in people with depression. Understanding this could help define anhedonia in more precise, brain-aligned terms.
- Clinical Application: Because the signal is easy to measure non-invasively, it could serve as an earlier outcome measure in clinical trials to predict if a treatment is restoring neural health before symptoms actually improve.
Source: University of New Mexico
James Cavanagh has been at The University of New Mexico for 13 years studying cognitive neuroscience. He has been well-supported by the National Institutes of Health in his quest to use imaging tools to understand psychiatric and neurological disorders.
His most recent publication is a theoretical review of a specific brain signal called Reward Positivity. This unique electrical signal is only sensitive to rewards: it emerges as a burst of positive voltage from about 200 to 500 milliseconds after someone gets a reward.
“It hasn’t been a long time since it was discovered,” said Cavanagh, a professor in the department of psychology. “We’re still trying to figure out what it means and why it’s so specific to this one type of outcome.”
This brain signal is evoked whenever a test subject is given a task and then given a dollar, or told “that’s correct,” or even just given a ‘thumbs up’ icon. This signal gets larger, the more surprising the reward is.
“This sensitivity to surprise aligns with a foundational theory underlying all learning,” Cavanagh said.
“Reinforcement learning is a fundamental algorithm that is used to understand learning in humans, vertebrates, computers, etc. It’s all based on how surprising rewards are.”
That means Cavanagh, alongside Clay B. Holroyd from Ghent University, has found a neural signal, tightly aligned with theory, that can be measured in humans noninvasively.
However, further work on this new theory has suggested that researchers may have been using the wrong terminology: they have made a fundamental mistake confusing “reward” and “goal.”
Rewards and goals usually align – but not always.
“A goal can be something you work towards. If you’re at Blake’s Lotaburger and you’re getting a drink, you might decide to get water instead of soda. The reward is the sugar, the soda. The goal is to be healthy,” Cavanagh said.
“It shows us something above and beyond the ideas of simple reinforcement learning—we’re seeing how people set what they’ve decided is important to learn. It’s like the brain checking off items on a list.”
Cavanagh said this distinction is critical. While “rewards” imply dopaminergic systems, the word “goal” implies this system is being used for higher-order cognitive control. This is the system that links high level control and low-level reward processes together.
He hopes to bridge this theoretical work with a practical, clinical application. This work was funded by a grant looking into anhedonia—the decreased ability to experience pleasure as it relates to clinical depression.
Cavanagh said they have a series of papers demonstrating that the Reward Positivity signal is smaller in people with depression, and researchers don’t know why.
“Now we have new motivation to probe this signal, what it means, why it’s smaller, and even leverage it for clinical benefit. For example, other groups have shown this signal can predict antidepressant response,” Cavanagh said.
Many clinical trials fail because they’re aiming for a very difficult target. Cavanagh believes testing the Reward Positivity signal could be used earlier in the process. Because it’s very easy to assess this signal, Cavanagh hopes this can be used as a phase two or three clinical trial outcome measure, meaning its effectiveness is tested on a large scale.
“Instead of just measuring somebody’s depressive symptoms, you could have a suite of small-scale tasks to see if brain markers that predict neural health are getting larger,” Cavanagh said.
“I think this also will help us on the theoretical end to define ideas that we use clinically, like anhedonia, to be more specific and more brain-aligned,” Cavanagh said.
Key Questions Answered:
A: Think of it as your brain’s “victory spark.” It’s an electrical signal that fires half a second after you get something good or find out you’re right. The more surprising the win, the bigger the spark.
A: Because they use different parts of the brain. A reward is a simple biological reaction (like liking soda), but a goal is a choice (like picking water for your health). Depression doesn’t just dull the “liking”; it may be disrupting the high-level “goal” system that connects our desires to our actions.
A: Currently, we wait weeks to see if an antidepressant works based on how someone feels. This brain signal could act as a “preview”—if the signal starts getting stronger after a few doses, doctors would know the treatment is working on a neural level long before the patient feels better.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this neuroscience and depression research news
Author: Anna Padilla
Source: University of New Mexico
Contact: Anna Padilla – University of New Mexico
Image: The image is credited to Neuroscience News
Original Research: Open access.
“The Reward Positivity signals a goal prediction error” by James F. Cavanagh and Clay B. Holroyd. Trends in Cognitive Sciences
DOI:10.1016/j.tics.2025.11.005
Abstract
The Reward Positivity signals a goal prediction error
The Reward Positivity (RewP) is an electroencephalogram (EEG) feature that emerges following performance feedback and is commonly understood to index both positive and negative reward-prediction error (RPE+ and RPE−, respectively) signals.
In contrast to this dominant perspective, we argue that the RewP is an independent EEG feature that selectively responds to positive RPE and is superimposed on a common background signal.
We further propose that the RewP signals a goal prediction error: it is elicited by abstract signals instead of by hedonic ‘rewards’. This goal prediction error appears to be produced by a critic-like architecture that is associated with the actor–critic framework in reinforcement learning.
This perspective emphasizes the role of the RewP in goal attainment and cognitive control as opposed to being a simple indicator of reward receipt.
