Writing stimuli. What gave you that sudden idea that made you urgently scribble it down? It’s worth exploring.
The power of olfactory stimuli in activating memory is well known. But it’s much harder to ‘dream up’ a smell that might affect the character in your story, than it is a sound or sight.
When we’re stuck for ideas for a visual stimulus, Art can provide perspectives, narratives, symbols to enrich our writing. For auditory stimuli, theatre and radio present us with ideas and emotions through sound patterns, speech or music. There is no equivalent for smells.
So having found the right sound or sight stimuli to cause your hero to pale with emotion how to find the right smell/scent/perfume/stink to cause emotional impact? Leave aside the obvious triggers: magnolia, blood, excrement, cabbage (who wants to write hackneyed stuff?). Will the character stop short as spinach fumes enter his/her nostrils, or candy floss? What particular scent might have been recorded in his/her long term memory?
You can prepare for that blank moment. How about noting down your own strong reactions to any smell, pleasant or unpleasant? List the source for each. This will make you rack your brains, and may well summon up incidents that you can use in your story. Add any smells that you already know act as powerful reminders for you – and write down why.
A scent for one person may be a stink for another. One perfume might raise very different memories for two different characters. Identifying that memory can enrich your story line. For instance, the whiff of musty clothes in a charity shop reminds Kara of a great aunt, but Debra of pass-me-downs when she was young. The scent of aloe vera takes Anna back to the birth of her baby, but reminds Dan of a little lane in Almeria where he was set on by teenage thugs. They find themselves quarrelling . . .
With such a list of smells, you can google them to add any interesting facts to their source and the memories they evoke for you. Strengthen your writing with that detail that enthralls readers and brings them right into your story.