The significance of Watsons work with the infant Albert is as follows.
He demonstrates, by "classical conditioning" with the infant Albert, that behaviour is learned/ conditioned. In other words, behaviour is not just influenced by biology, the determinant of such is not solely innate, rather it is also shaped by our experiences.
With respect to the case in point, the infant Albert, where a conditioned stimulus (Albert's action of reaching for the rat) and an unconditioned stimulus (loud noise created by Watson banging steel bar with a hammer behind infants ears) are paired repeatedly, the unconditioned stimulus singly (loud noise) is recognized by Albert and creates a conditioned response (fear and crying) (M, p.84)
For students of psychology this is seen as evidence that behaviour is, to a large extent, shaped by environment. If our environments are manipulated to create a reaction, we can say that, that reaction is then determined by our environment. Thus behaviour is not just determined by biological makeup but also how we are nurtured, by our experiences. By those experience we learn to behave in a particular way.
What do you think is the determiner of behaviour, nature, nurture or both ?
Moghaddem,F. M. (2005). Great ideas in Psychology: A Cultural and Historical Introduction. Oxford: Oneworld Publication).