Evidence from multifeature whole-report in visual short-term memory suggests that not all misbinding is swapping

Forgetting is an everyday part of life but its precise mechanisms are incompletely understood. Recall errors are often not random. Rather, people often incorrectly report information about the wrong object in memory. In short term memory, this has been referred to as "misbinding". Here, it has commonly been assumed that the features of an object get swapped around in mind. However, an alternative mechanism is that information about a feature of one object might be lost, and replaced by another object's feature. Commonly-used cued recall approaches are blind to this distinction, but testing multiple objects on the same trial has the power to detect this. We asked people to report all features of all objects from an array (multifeature whole-report) in any order (free recall). This enabled us to directly quantify these subtypes of misbinding in memory. We introduce a probabilistic model that shows that misbinding actually includes a mixture of symmetric swaps and asymmetric misattributions where a forgotten feature gets replaced by a feature of another object in memory without a reciprocal exchange. This distinction is observed even when memory objects are encoded sequentially.