Vasanas and Samskaras:
The "smell" of latent impressions
Some people are born with an innate talent to do certain things. This can be a talent to play a sport, in music, in math, in service and empathy or in things of spiritual nature. Modern science attributes this talent to how our neurons are wired together with proclivity for certain actions. It further states that this wiring is part random, part hereditary and part due to upbringing. The Jyotish (vedic astrology) system attributes it to the planetary influences in conjunction with the views of the yogic system (which we will see next).
The yogic system, on the other hand, believes that this is due to latent impressions on the Purusha (the atma or loosely translated as the soul) from past lives. These latent impressions are called "Samskaras". The yogic system further states that for the samskaras to manifest into talent or ability to do certain things, the right conditions need to exist. Otherwise the Samskaras will just be latent impressions like seeds waiting for warmer weather to sprout. However, when the conditions do exist, then one radiates a certain energy causing the subliminal imprints (samskaras) to manifest in full flow. When the samskaras manifest in this fashion, it is said that the vasanas are strong. "Vasana" literally means smell. It refers to the emanative power of the samskaras.
Samskaras are the subliminal impressions
Vasanas refer to the emanative nature of these subliminal impressions
2) The Yoga Sutras on Vasanas and Samskaras
ततःतत् विपाकाणुगुणानाम् एव अभिव्यक्तिर् वासनानाम् (Y.S. 4.8)
Tatah tat Vipaka Anugunanam eva Avibhyakhthir Vasananam
From these (three types of Karma), only those Vasanas fructify which have favorable conditions to manifest
This is an important sutra. Patanjali, in the previous sutra, defines Karma to be of three kinds - good, bad and neutral. He, further says that the actions of a yogi are neither white nor black, meaning they are beyond good and bad and hence do not add to the storehouse of karma for the yogi making him/her closer to kaivalyam (liberation). In sutra 4.8, he says that only those impressions that have the favorable conditions in a lifetime fructify. An example that is commonly given by authors like Edwin Bryant is that of the cicada. The cicada lays dormant under the soil for about 17 years waiting for the right soil temperature and other soil conditions. Then they emerge, mate, lay eggs in a span of 4-6 weeks and die.
Cicadas emerging in the millions
A cicada emerging after 17 years
In the next sutra Patanjali goes on to say that memory (Smrithi) and samskara are identical even though they may be separated by birth, place and time.
जाति देश कालव्यवहितानाम् अपि आनन्तर्यम् स्म्रिति सम्स्कारयोरेकरुपत्वात् (Y.S. 4.9)
Jati desha kala vyavahitanam api anantaryam smrithi samskarayor eka roopatvat
Memory and Samskara are identical and therefore there is an uninterrupted connection between them, even though they may be separated by birth, place and time.
Every thought or action leaves an imprint in our chitta (mind) and this carries forth across lifetimes, according to Patanjali. Patanjali also says that memory and Samskara are one and the same.
3) Why pushing and goading have limited effects ?
A corollary of sutra 4.8 is that pushing and goading our loved ones to do what we perceive to be good actions may not be helpful if they lack the subliminal desire to do that action (or) if the desire does exist, the conditions for the desire to sprout forth don't. Pattabhi Jois would tell his students that finding any form of yoga in this lifetime is itself a great boon brought about by the accumulated good karma in past lifetimes, for it takes the person a step closer to Kaivalyam (liberation).