Tracking object number or information load in visual working memory: revisiting the cognitive implication of...

Area of Science:

• Cognitive Neuroscience
• Psychology

Background:

• The contralateral delay activity (CDA) is an electrophysiological marker linked to visual working memory (VWM).
• Two competing theories explain CDA: the object number account and the information load account.

Purpose of the Study:

• To differentiate between the object number and information load accounts of CDA.
• To investigate how object quantity and information complexity influence CDA amplitude.

Main Methods:

• Participants performed VWM tasks remembering either two or four arrows.
• Arrow stimuli varied in resolution (low vs. high) to manipulate information load.
• CDA amplitude was measured using electroencephalography (EEG).

Main Results:

• CDA amplitude was higher for four arrows than two arrows in the low-resolution condition.
• No significant difference in CDA amplitude was found between low- and high-resolution objects for either two or four arrows.
• CDA amplitude for four high-resolution objects was significantly lower than for four low-resolution arrows.

Conclusions:

• The findings support the object number account of CDA.
• CDA amplitude is primarily determined by the number of distinct objects maintained in VWM, rather than the informational complexity of those objects.