Dynamically Adjusted Motion Prediction Task (DAMP)

Background

The Dynamically Adjusted Motion Prediction Task (DAMP) is a motion-based decision making task that was designed by Markus Ullsperger and D. Yves von Cramon in 2003 specifically for fMRI studies to isolate the neural networks responsible for processing entirely externally provided "negative" versus "positive feedback".

The task presents participants with two competing moving balls that start at different locations and move at different speeds towards a finish line. For example, the slower ball starts at a position closer to the finish line but the faster ball moves faster and might overtake it. Before the balls can reach the finish line, the trial stops, and participants are asked to decide quickly which ball would reach the finish line first before visual performance feedback is provided in the form of a sad or happy (or indifferent) smiley. Because the balls disappear long before they reach the finish line, participants cannot see who actually wins and cannot evaluate their own performance. Moreover, a dynamic algorithm artificially locks every participant into a ~40% error rate making them highly uncertain about their performance. Thus, they completely depend on the externally provided feedback to know if they had succeeded or failed with their prediction.

By enforcing a relatively stable high error rate, Ullsperger & v. Cramon further ensured a robust number of positive and negative feedback events across all subjects, maximizing the data quality for the fMRI scanners. Because the DAMP task dynamically scales difficulty trial-by-trial, the subject's level of cognitive effort, focus, and subjective task difficulty remains perfectly uniform throughout the experiment.

By utilizing the DAMP, Ullsperger & v. Cramon successfully mapped out a distinct "reward vs. punishment" division of labor in the human brain when receiving feedback. Positive feedback for correct predictions selectively activated the reward system, specifically the ventral striatum (nucleus accumbens). Negative feedback for incorrect predictions activated a specific performance-monitoring network consisting of the rostral cingulate motor area (rCMA), the inferior anterior insula, and the epithalamus (habenular complex).

Task Procedure

The Millisecond DAMP procedure consists of two phases: a baseline phase that assesses the threshold for arrival time differences (in ms) - the point participants start guessing- with an interweaved double staircase procedure and a test phase that runs a total of 120 trials keeping the error rate approximately at 40%, using the established baseline threshold.

In each trial, one ball acts as the 'base' ball that would always reach the finish line after 7000ms (measured from onset of trial). The second ball is the 'target' whose speed is determined to be 60%,70% or 80% above (with a probability of 60%) or below (with a probability of 40%) the assessed threshold. The horizontal start positions of the two balls are staggered with the constraint that they cannot be same. Each ball has a 50% chance of being the top ball in the display. Each moving display is terminated after 1430ms. Participants then have 1500ms to press key 1 (for the top ball) or key 2 (for the bottom ball) to make their prediction. A happy smiley face is presented for correct predictions. A sad smiley face is presented for incorrect predictions, and a neutral face appears if participants missed the response window.

What it Measures

The Dynamically Adjusted Motion Prediction Task (DAMP) is a 'decision-making under uncertainty' experimental paradigm with external performance feedback that is primarily utilized as a diagnostic probe for the study of the brain’s neural substrates relating to performance feedback.

Psychological domains

• Perceptual Decision-Making: The ability to gather sensory data (speed and trajectory), evaluating it and using it to make a decision
• Spatial and Temporal Extrapolation: The ability to track moving objects and calculate velocity mentally

Main Performance Metrics

The task does not track any specific performance metrics.

Psychiatric Conditions

Because the DAMP paradigm isolates the brain's response to external performance feedback, it serves as a benchmark for measuring what goes wrong in clinical disorders linked to reward processing and performance monitoring, e.g.

• Schizophrenia
• Depression (Major Depressive Disorder)
• Attention Deficit Hyperactivity Disorder (ADHD)

References

Search Google Scholar for peer-reviewed, published research using the Inquisit Dynamically Adjusted Motion Prediction Task (DAMP).

---

Ullsperger, M. & Crampon v., D.Y. (2003). Error Monitoring Using External Feedback: Specific Roles of the Habenular Complex, the Reward System, and the Cingulate Motor Area Revealed by Functional Magnetic Resonance Imaging. The Journal of Neuroscience,23(10),4308–4314.