Biological preparedness is a concept that proposes that organisms innately form associations between some stimuli and responses. Behaviorists use this concept as a main tenet in classical conditioning. Some associations are easily made and are thought to be inherent while some are formed less easily. An example of an easily formed association is taste aversion (such as the Garcia Effect).
If you become ill from eating something you will have an aversion to the taste and smell of that particular food in the future. Phobias also are easily formed associations through classical conditioning. Learning to fear dangerous stimuli develops easily and quickly as an evolutionary adaptation to avoid danger.