Limits of verbal labels in cognition: Category labels do not improve visual working memory performance for obfuscated objects

Across many studies, verbal labels have been shown to significantly affect perceptual and cognitive processes. Here we ask whether verbal labels can also improve visual working memory performance by making objects more recognizable. In a series of experiments, participants were asked to remember visual details of unrecognizable shapes derived from real-world objects. Participants were either provided with category labels prior to stimulus presentation or not. We reasoned that the labels could aid object recognition, which would then help maintain them in working memory based on recent work showing that meaningful, recognizable objects are better remembered than arbitrary visual shapes. Contrary to our hypothesis, we found no reliable increase in visual working memory performance when participants were given verbal labels. This pattern of results persisted across various experimental manipulations, including different methods of distorting the objects, testing label memory, and using within or between-category stimulus sets. Overall, our results indicate that category labels did not readily enhance working memory performance for obfuscated shapes that are difficult to recognize, suggesting that improving visual working memory for meaningful stimuli may depend on how the visual system reorganizes incoming visual information perceptually rather than associating visual inputs with verbal knowledge. Thus, verbal labels do not seem to have as broad and general effects on cognitive functioning as previously assumed.