Taking a leisurely walk that culls up random memories can be similar to reading a novel with layers of flashbacks.
There is a purpose to a walk, while the memories are part of the head chatter that keeps our minds busy. Flashbacks – a sudden, brief relocation to the past before returning to the present – should not fall into this role.
I just finished a book that had flashbacks within flashbacks and whipped me around time and place that I almost put the book down, except I wanted to find out the end of the story. I had to flip back pages to reclaim where I was, interrupting the flow of my wanting to inhale the story.
Writers don’t want readers to go backwards, unless it’s to reread a beautiful passage or to review after putting the book down for a long (a very long) time.
Flashbacks should be used sparingly and serve a clear purpose, so that they don’t slow down the story. Their purpose can be to influence later events, reveal character and motivation, explain an event or add depth to the story.
A flashback interjects an incident from the character’s past. It can be presented as a reflection, a snatch of memory, a dream or dialogue. It can tell back story, or what occurred before the actual event, kept on a need-to-know basis.
Flashbacks should be avoided in the opening scene or in a major action scene, nor used if they do not relate to the current unfolding of events. Cues such as color, scent or sound can indicate the end of the flashback.
Just like with a walk.
But this time the cue returns you to reality after getting lost in thought, a nice place to be but not if it is in a novel or story.
See Zoey the dachshund’s blog on the same topic at http://zoeyspaw.wordpress.com/2012/04/29/dog-gone-memories/.