The self-centered materialistic ego, thus being transformed into three features, becomes known as the modes of goodness, passion and ignorance in three divisions, namely the powers that evolve matter, knowledge of material creations, and the intelligence that guides such materialistic activities. Nārada, you are quite competent to understand this.
(Srimad Bhagavatam---2:5:24---purport).

Materialistic ego, or the sense of identification with matter, is grossly self-centered, devoid of clear knowledge of the existence of God. And this self-centered egoism of the materialistic living entities is the cause of their being conditioned by the other paraphernalia and continuing their bondage of material existence.
(Srimad Bhagavatam---2:5:24---purport).

Since the Supreme Personality of Godhead, is ever existing, all-blissful and full of knowledge, His different energies are also ever existing in the dormant stage. Thus when the mahat-tattva was created, it manifested the material ego and swallowed up the darkness which covered the cosmic manifestation at the time of dissolution. This idea can be further explained. A person at night remains inactive, covered by the darkness of night, but when he is awakened in the morning, the covering of night, or the forgetfulness of the sleeping state, disappears. Similarly, when the mahat-tattva appears after the night of dissolution, the effulgence is manifested to exhibit the variegatedness of this material world.
(Srimad Bhagavatam---3:26:20---purport).

The material ego springs up from the mahat-tattva, which evolved from the Lord's own energy. The material ego is endowed predominantly with active power of three kinds-good, passionate and ignorant. It is from these three types of material ego that the mind, the senses of perception, the organs of action, and the gross elements evolve.
(Srimad Bhagavatam---3:26:23-24---purport).

Progress in cultivating the human spirit entails the gradual disappearance of the materialistic ego. Covered by ignorance, passion, and so-called goodness, the spirit soul thinks himself all in all and is covered by a false sense of ego. Thus he falsely identifies the soul with the body, and his bodily relations with material things become the objects of his attraction. This false identification and attraction for matter gradually dry up and fade away by success in the cultivation of the human spirit. That is the effect of such higher cultivation. Progress in spiritual culture brings about the disintegration of false ego and material attraction.
(Light of the Bhagavata).