I believe the tendency of aspies (particularly children in the “active but odd” stage of development) to anthropomorphize specific classes of objects (such as pencils) can be explained by a brain that is specialized for domain-specific expert pattern recognition.
There’s a region of the brain called the right inferotemporal cortex that becomes highly active in facial recognition. It is colloquially thought of as “the face-reading module” because when it is damaged, face-reading is usually the functionality that is lost. But it is probably the case that face-reading is just a particularly difficult pattern recognition problem that almost all humans are very good at, and the brain is better able to regain functionality for easier pattern recognition problems.
You can give people a new class of objects, called “greebles”, and train them over the course of weeks to recognize them by name and family paying close attention to certain features that unite families.
If you give a student an fMRI in the early stages of this task, you’ll see a lot of blood flow to several brain regions while they familiarize themselves with gross features of this new category of objects. But as the task progresses and they become experts at spotting familial traits and particular individuals in these greebles, an fMRI will begin to show blood flow concentrated much more specifically in the inferotemporal cortex (indicating the use of expert pattern recognition) and in a couple of tiny regions specialized for the task.
You can probably sense that, if you became an expert in greebles, all of them would feel a little different upon recognition as if their features, names, and family names gave them personalities, biographies, and dispositions toward one another. I think it is not a stretch to say that we tend to become experts much more quickly in perceptual tasks that have strong emotional salience, such as reading personalities through face-reading (phrenology), or reading political messages in symbology, or pointed emotional messages from a romantic interest in the language of flowers.
The Asperger’s personality is characterized by extreme levels of knowledge specialization and expert pattern recognition within these domains, specific to each aspie. Therefore, it makes sense that a child with Asperger’s would name all of his pencils and be inappropriately upset when they have to be replaced with new pencils- his brain has applied enormous emotional salience to those pencils such that his right inferotemporal cortex could tell the difference between another red pencil and “Pete” from one hundred feet.