+1 for the explanation. "Priming" is another term that describes this phenomenon. From wikipedia: Priming in psychology refers to activating parts of particular representations or associations in memory just before carrying out an action or task. In a neurological view priming can be seen as the activation of clusters of neurons. An interconnected cluster is surrounded by other clusters that are more or less connected with each other...So when the cluster that represents the concept of "flower" is activated, particular clusters will be more activated then others (i.e. kinds of flowers).