Today learning theorists state that learning is more than just classical and operant conditioning. It is also influenced by biological, psychological, and social-cultural influences. If you recall associations are made to fit the needs of survival, we learn the things and repeat then that aid in survival. Before theorist thought that any stimulus can be conditioned to behaviour but it turned out that it is not the case. Animal"s capacity for conditioning is restrained by its biology because each species predispositions prepare it to learn the associations that enhance its survival. Ex: wolves were given a sheep injected with sickening poison to eat. Their sicken upon eating the sheep caused them to avoid eating all sheep in general (they avoided the sheep due to getting sick so that they can increase their survival) If a conditioned stimulus is ecologically relevant to the animal, it may serve as a stronger stimulus to behaviour.