the environment and this adjustment can happen in a few milliseconds. More specifically, a study from [@clifford2007visual] reveals that the face recognition process happens at a higher level of cognition, and later at the stage of visual encoding, we observe that the sensory systems adapt itself to the prevailing environment. This shows that HVS relies heavily on the prior estimation of the objects’ appearance distribution to improve the perception capability at the current time-stamp.

Moreover, the adaptation happens both in the “low” and “high” level visual features. The human visual system adapts to the distribution of “low-level” visual features such as color, motion, and texture, as well as the “high-level” visual features such as face classification including identity, gender, expression, or ethnicity [@webster2015visual]. This adaptation can be both short-term and long-term. For instance, our perception system adapts itself to the general visual features of the environment which we are living in for a long time such as faces and colors (like training a model). Also, it can adapt itself dynamically when the environment changes, for example, moving from the indoor environment to the outdoor [@webster2015visual] (like adapting a shallow model). This adaptation capability is essential for our HVS to perform 