Clearly referring to ideas, subjects and objects throughout the text

If we do not refer to ideas and things clearly and consistently throughout the text, the thread of meaning is lost and the chain (of ideas) is broken. This often results in the reader of your text being unsure what point you were making or being unable to follow your argument.

For example:

Information is received from the environment by a range of sensory registers that reside in sensory memory. The sensory receptors are modality specific: a register exists for each sensory modality such as vision, auditory and olfactory. These have the ability to transform stimuli from the environment into physiological representations, which can be understood and retained in the memory system. They therefore have a key role to play in human cognitive processing. Sensory registers also play a role in the larger system of memory.

The model paragraph shows that there are several ways you can refer to the same thing.