External, gross and fine-motor actions, such as opening a book,
can be seen, and understood, and prompted and their further implications and meanings grasped

Sensory process are not so visible.

Associative central psychological processes such as thinking cannot be observed directly.

This presents a problem for the t.r.a. type of communication

The solution is to adopt a figurative approach

Examples, 'weighty matters', 'deep thoughts' etc

These verbal analogies can be represented visually

So our little girl in the picture above supports/rests her head on her hand or hands, because her head is full of heavy thoughts

Compare these analogies, wherein complex psychological processes are represented by simpler physical phenomena, with what happens in tests such as the H.T.P. As an example consider the symbolism of a strong wind blowing on a person or a tree as representing psychological pressure on a child, e.g. from his parents, to grow up, do well at school etc. Here the psychological pressure is a pattern of parental expectations, promises and bribes to the child should he succeed in satisfying the parents' demands, and threats and blackmail should he fail.
The above really involves two concepts or dimensions of the measurement of physical attributes of physical matter,
1. weight, mass
2. volume
So the head is heavy, not just because it has heavy, serious thoughts, but because it is full of thoughts. Contrast this with someone described as being empty headed