The cognitive aspect of second language learning, specifically by immersion method, is discussed from a biological perspective. The approach taken is that of "connectionism," a recently-developed theoretical and experimental approach to human cognition. It is argued that while general cognitive functioning is unaffected by language immersion, immersion students are subject to shifts in information processing strategy toward the visual system and away from the auditory system, due to low speech comprehension ability, and that development of such a bias is a natural outcome of brain structure and the mechanics of information processing in the human brain. It is further proposed that any cognitive advantages and disadvantages accrued by learners in immersion situations are determined by the information processing demands of the particular measures of cognitive performance used. Academic achievement results for this group are also explained by how achievement is defined and success measured, from the perspective of information processing. Contains 24 references. (MSE)