It is only logical to assume that function was first to emerge, since we can't tell for sure when aesthetics and design got fused with the construction of dwellings and artifacts. The following diagram shows the intersection of Form and Function, in relation to the shift from use of found objects to modern manufactured products, which depends heavily on design (Form) as a competitive advantage.

Early humans sought shelter from the elements and predators in caves and other types of nature-made dwellings, which could be used with little or no modifications. They also used found-objects such as rocks and sticks as utensils and weapons. It can be reasonably argued that in those early times, function topped form, because there was no other option --you need to use whatever works regardless of its look and feel. In the diagram, the bulk of found objects use (A) positioned within the Function circle.

With early use came experience, habit, familiarity, and the ability to recognize a functional fit in similar found objects--which was very important for a nomadic culture on the move. Over time, patterns of use assimilated in the way of life and customs of a culture, passing from generation to generation.

In the preceding diagram, the small part of A that is within the intersection of Function and Form, is an acknowledgement of the existence of some inherent ability or instinct, to recognize the potential of specific found objects to serve specific functions. In other words, some type of decision-making, of selectiveness, had to be applied by our ancestors to help them determine which rock would make a better weapon, or which cave will be more protective.

We share this ability with many other species and it seems especially evident in the use of found objects for the creation of dwellings, as we can see in birds, bees, ants, and beavers who create large and elaborate structures, as shown in the following image. These animals are selective when they collect the materials from which they assemble their shelter. 

Selectiveness means recognizing the availability of choice. Choice, in turn, means having to decide which item, among similar items that fit a function, is better. If all options qualify on a functional level, there is an opportunity to use additional criteria, which is less objective, but rather a reflection of personal preference. The preference is an individual's response to sensory properties of the item, such as the material it is made of, shape, texture, and color.

We don't know for sure about animals, but we have all experienced the feeling that an item is "just right" for us. This confidence is often accompanied with a physical sensation of internal calm and comfort, which follows an evaluation phase of other options. The decision-making process, involves rational and emotional behavior.

The following diagram illustrates the two primary types of experience evaluations:

• Rational (function first)
• Emotional (form first)