It's important to first settle on a definition for a predictor. Generally, the following is accepted.

A predictor variable is a variable that can be used to predict the value of another variable (as in statistical regression)

www.thefreedictionary.com/predictor+variable

When you open a prediction, the Top Predictors page appears. The spiral visualization you see shows you the top key drivers or predictors (in color, with other predictors in gray). The closer the predictor is to the center of the spiral, the stronger that predictor is.

There is a visualization generated for each key predictor, giving you information about what drives each behavior and outcome. If you click on one of the predictors (or hover over it), you can  see some details about it. Each predictor has a corresponding snapshot visualization that contains information about the predictor and how it affects the target. The color of the circle in the spiral visualization is also found in the corresponding detailed visualization.

In our prediction, the blue circle in the spiral visualization for the DaysFromSupplierToAssembly predictor is included in the corresponding detailed visualization for DaysFromSupplierToAssembly (shown here) and if you click on the visualization, you can see it in more detail on the Main Insight page:

Once Watson has created a prediction, you are not locked in to what you specified on the Create a New Analysis page. You can dive deeper using the prediction scenario selector (shown here) to specify how many fields you want to view that act as predictors for your target. In our prediction, what might we combine with DaysFromSupplierToAssembly to be a more exact predictor of fulfillment time?

If you select Two Fields, you see a new set of visualizations and see how those two variables influence the target. If you select Combination, the visualizations provide a deeper and more predictive analysis, displaying how a combination of the variables influences the target.