Advances in the study of DNA and the use of sophisticated brain-scanning equipment has enabled scientists to understand in increasing detail how our human memory operates. One significant discovery has been that we appear to possess different types of memory. Our long-term memory, for example can now be distinguished as being physiologically distinct from our short-term memory.

To a pure scientist the subject is highly involved, but for simplicity, this website uses the term 'explicit memory' to refer to our short-term memory, and the term 'semantic memory' to apply to those long-term memories stored in the subconscious part of our mind, and which associate together to help form our concepts (see note on concept.)

But Stanley also had a third type of memory. Most of us do not retain the details of our explicit memory for very long. Usually they sink into our long-term semantic memory. But Stanley had the gift of being able not only to distinguish his explicit memories from his semantic memory at almost any time, but to recall them when he wished with great accuracy. Scientists call this type of memory 'episodic' memory.

The gift of episodic memory seems to have been a Spencer family characteristic. His pianist brother Will, for example, could memorise a sheet of music or a restaurant menu at one reading. Confined to bed in his final illness in 1954, he buoyantly explained that even if I go blind, I shall always have my books with me.

Stanley's use of episodic memory would at first sight seem destined to keep his art firmly on the down-to-earth. But we shall go on to see how ingeniously he used it to raise his vision - and us - into his up-in-heaven.