The article deals with a controversial issue, namely the effect of architecture and the built environment on human behaviour. Two debatable approaches dominated the architectural field in the past decades: determinism and possibilism. Both have proved inadequate in explaining human-environment relationships. Probabilism emerged as a tradeoff, providing an interface that accentuated the role of architecture in influencing human behaviour. The article presents a theoretical framework to explore the concept of probabilism, and the extent to which architectural intervention can affect the perceptual and cognitive behaviour of individuals. A psychophysical study is conducted on a selected environment (University of Baghdad campus) based on two approaches: the cognitive representation and mental mapping of individuals (the graphic recall), and the perceptual selectivity of environmental elements (the verbal recall). The findings assert the significant impact of the physical aspects (semblance and positioning attributes) of environmental stimuli, thereby accentuating the probabilistic approach to human behaviour.