Object-based encoding constrains storage in visual working memory.

Area of Science:

• Cognitive Psychology
• Neuroscience
• Visual Perception

Background:

• The fundamental unit of visual working memory (WM) remains a subject of debate.
• WM capacity may be constrained by the number of distinct objects or the total number of stored feature values.

Purpose of the Study:

• To investigate whether object-based or feature-based models better explain the encoding of multi-feature objects in visual WM.
• To determine the capacity limits when storing objects with multiple features (color/orientation, color/shape).

Main Methods:

• Four experiments employed a whole-report task.
• Participants reported both features from a six-item array of multi-feature objects.
• Analysis focused on recall performance for single- and multi-featured items.

Main Results:

• Above-chance recall for both single- and multi-featured objects was limited to the first three or four responses.
• Later responses were best explained as random guesses.
• Recall patterns indicated a distribution of features across objects.

Conclusions:

• The findings support an object-based limitation on visual working memory capacity.
• Visual working memory capacity is constrained by the number of individuated objects, not the total number of features stored.