Efficiency of abstraction of such properties of objects as colour, form, and size, depending on the type of their designation with words has been studied. It is shown that the manner of designation is particularly important for abstraction of the size and less so for abstraction of the colour. The stronger physiologically is the property to be abstracted the less is the necessity to mark it by words in order to abstract from the object both the property itself and other properties belonging to neighbouring categories, and vice versa. It has been also established that the less integrated into the categorical structure of the object a property is the more important is the role of its verbal designation. Words are also needed when abstraction is to be performed in the absence of visual supports as compared with visually controlled operations.