Answer:
cognitive psychology
Step-by-step explanation:
Cognitive psychology is that branch of psychology which deals with mental process such as thinking, learning, memory attention, etc. In more simple words it unfolds the human brain works. Practical application of cognitive psychology includes improving decision-making capacity, learning disorder, recovering from brain injury, etc.
As per the question, when we use our brain for reasoning and not just for responding to environmental factors is an argument of cognitive psychology.