If you look at the psychological drivers of the Roman society during the early Republican period you see the influence of tribe, family, and culture.
The early Republicans were tribal -- three original tribes whose leaders became the patrician class -- and then additional tribes added over time to reach a total of thirty-five. This merging of Roman tribes is an interesting contrast to others in Italy and Gaul which resisted cooperation. Five hundred years after the Romans adopted a combined tribal structure the Gauls were still separated.
Within the tribal system, the people were organized by gens and family. Gens is the class of families with the same nomen or name. For example, Publius Cornelius Scipio (Africanus) had the nomen Cornelius because he was a member of the gens Cornelii. His brother was Lucius Cornelius Scipio. Their father was Publius Cornelius Scipio. There grandfather was Lucius Cornelius Scipio. Gens affiliation was fundamental to the power structure of the government – particularly in the Senate, as father, son, nephew, and cousin were all elected to serve.
Within each gens was the nuclear family, under control of the paterfamilias or senior adult male. This individual exerted absolute control over all other family members with regard to lifestyle, education, and wealth. Women and children had no rights; they were solely under control of the males. Roman families engaged in ancestor worship. The homes of the wealthy contained a shrine called the Lararium containing masks of ancestors. Prayers were offered at the shine asking the deceased to watch over and protect the living. The living sought to bring honor to the dead – to carry on the family name with distinction.
Romans were strongly committed to principles they felt were fundamental to life. These principles included personal virtues: Dignitas (having dignity), Gravitas (a sense of importance), Pietas (respect for the nature order), Veritas (truthfulness), and public virtues: Concordia (Harmony among the Roman people), Fides (Good faith), and Virtus (Courage). Many times Rome went to war for honor, because she had engaged in treaties with implied Fides. If the friend was attacked, good faith required assistance against the aggressor.
Gens and family retained their importance even into the time of the Empire. The tribal organization, however, disappeared as a more modern societal model came into being.