In Shakespeare's play, Macbeth, the social influences are very closely tied to the political influences of the day.
Early on, we learn that Macbeth is a valiant warrior for his friend, cousin and King, Duncan. He does all in service of the King. So much of what the audience witnesses pertains to Macbeth's interactions first with Duncan, and later with the political court—specifically Banquo, Malcolm and Macduff.
The clearest indications of social influences can be seen in the belief in the supernatural, and the state of the poor in Scotland at the time. In terms of the supernatural, the belief in things "not of this world" are obvious in the presence of the witches and society's beliefs in their power, as well as unnatural occurrences believed to be brought about by the disruption of order in the Great Chain of Being, also something strongly woven into the fabric of society.
Belief in the power of the witches is expressed when Banquo realizes that the witches' prediction that Macbeth would be named Thane of Cawdor comes true. Banquo's comment reflects the belief that witches (or he who they serve) could only tells lies:
Another incident that reflects the belief of society during Shakespeare's time is the Great Chain of Being. It was believed that God ordained who would be king, and that each person was born into a hierarchical chain of importance: if one was born as a nobleman, God wanted him there. If one was a peasant, it was God's plan. However, when man disrupted this order, as Macbeth does when he kills the "God-ordained" King—Duncan—and takes his place, the order of the universe is upset and strange things in nature take place:
What, can the devil speak true? (I.iii.113)
...By the clock ’tis day,
And yet dark night strangles the travelling lamp.
Is't night's predominance, or the day's shame,
That darkness does the face of earth entomb,
When living light should kiss it? (II.iv.7-11)
Ross reports an eclipse, when it is like night—during the day. Then the old man notes other strange occurrences:
Even like the deed that's done. On Tuesday last
A falcon towering in her pride of place
Was by a mousing owl hawk'd at and kill'd. (12-15)
Ross speaks of a falcon, a powerful predator, which was attacked and killed by the weaker mousing owl. Ross also reports that the King's horses have gone wild, broken their stalls and attacked men:
And Duncan's horses...
Turn'd wild in nature, broke their stalls, flung out,
Contending ’gainst obedience, as they would make
War with mankind. (17, 19-21)
The other example of social influence can be found in the plight of the very poor in Scotland—the same as any other country, in any other time: men will do anything to save their children. Macbeth convinces poor family men that Banquo is responsible for their poverty (which is actually Macbeth's fault), and he convinces them to kill Banquo saying that he (Macbeth) cannot do so for political reasons. The poverty-stricken men agree to take Banquo's life to better the circumstances of each man's family. One murderer says what he is willing to do for a better life:
And I another
So weary with disasters, tugg'd with fortune,
That I would set my life on any chance,
To mend it or be rid on ’t. (III.i.120-123)
In these situations, we see social influences running through the pages of Macbeth, reflective of Shakespeare's time.