We also identified a group of "helper" words we call "approximations" (e.g., slightly, near, almost, just). They seem to express categorization of a stimulus by opposition to another category (i.e. "not cardinal") and their use predicted recall bias away from the diagonals.

We used correlations to quantify the extent to which word use predicted recall error:

- Word use for "diagonal" and “left + right” predicted an increase in VWM error.
- "Horizontal + vertical" together negatively correlate with VWM error.

We plotted how often these words were used for each stimulus type and rotation angle (see the colored distributions in the radial plots). When plotted together with the recall error (in gray), we can see the relations between the two.

We grouped these words into strategies. Spatial language (i.e. words like "left" and "right", "diagonal", "vertical" and "horizontal") was the most commonly used strategy. Within spatial language, we identified the more frequently used words (see panel B).

108 participants performed a visual WM task and a naming task with the same stimuli. Cardinal biases are evident in the WM task results (panel C) and the raw naming task results show that some words are used more frequently and consistently across participants (panel D)

How do people use words when memorizing low-level visual stimuli? Subjects frequently report word use and prior work shows that verbalization improves recall. Can we understand recall behavior better by understanding how subjects label visual items?