The symptoms of highly developed devotional service for Kṛṣṇa, which are exhibited by the pure devotees, are sometimes imitated by those who are not actually pure devotees. This is described in the Bhakti-rasāmṛta-sindhu. Without devotional service to Kṛṣṇa, such symptoms are artificial, not actual. Sometimes those who are not conversant with the science of devotional service are captivated by the exhibition of such symptoms, but learned devotees know that they are simply imitation.
According to the various divisions and gradations of devotees, permanent devotional attitudes can be divided into five categories: (1) peacefulness, (2) service to Kṛṣṇa, (3) friendship with Kṛṣṇa, (4) parental affection toward Kṛṣṇa, and (5) conjugal love for Kṛṣṇa. Each division has its own taste and relish, and a devotee situated in a particular division is happy in that position. Characteristic symptoms exhibited by a pure devotee are generally laughing and crying; when emotions are favorable, a pure devotee laughs, and when emotions are not favorable, he cries.
Situated above these two emotions is permanent love, which is called sthāyi-bhāva. In other words, when one's attachment to Kṛṣṇa is permanent, one is situated in sthāyi-bhāva. That permanent loving attitude is sometimes mixed with different kinds of taste, called vibhāva, anubhāva and vyabhicārī. Vibhāva is a particular taste or attachment for Kṛṣṇa, and it can be divided into two further categories—ālambana and uddīpana. In the Agni Purāṇa and other authoritative scriptures, that which increases one's love for Kṛṣṇa is said to be vibhāva, and when Kṛṣṇa is the objective, vibhāva is described as ālambana. Uddīpanas include Kṛṣṇa's transcendental qualities, His activities, His beautiful smiling face and the aroma of His body, the sounds of His flute, ankle bells, and conch shell, the marks on the soles of His feet, His dwelling place and His paraphernalia of devotional service (such as tulasī leaves, devotees, ceremonial performances and Ekādaśī). Anubhāva occurs when feelings and emotions within oneself are exhibited. In the attitude of anubhāva, one dances and sometimes falls down, sometimes sings loudly, shows convulsions, yawns and sometimes breathes very heavily—all without concern for circumstances.
The external features exhibited on the bodies of devotees are called udbhāsvara. The vyabhicārī symptoms are thirty-three in number, and they primarily involve words uttered by the devotee and various bodily features. Different bodily features—such as dancing, trembling and laughing—sometimes mix with the vyabhicārī symptoms, which are also called sañcārī. When bhāva, anubhāva and vyabhicārī symptoms are combined, they make the devotee dive into the ocean of immortality. That ocean is called the bhakti-rasāmṛta-sindhu, the ocean of the pure nectar of devotional service, and one who is merged in that ocean is always rapt in transcendental pleasure on the waves and sounds of that ocean.