Final answer:
The basal ganglia, supported by the prefrontal cortex, are primary contributors to habit formation in the brain, allowing for efficient processing of routine behaviors. Habitual actions, facilitated by neural pathways, can be performed with minimal conscious thought.
Step-by-step explanation:
The portion of the brain responsible for causing us to perform tasks out of habit is primarily the basal ganglia. These deep brain structures are involved in a variety of processes including control of voluntary motor movements, procedural learning, routine behaviors or habits, and emotion. When we engage in habitual activities, such as walking through a grocery store without consciously thinking about each step, we are relying on the basal ganglia to manage these patterns of behavior efficiently.
Another part contributing to our automatic behaviors is the prefrontal cortex, which plays a key role in the planning of complex cognitive behavior, personality expression, decision making, and moderating social behaviour. Over time, as a task becomes habitual, the prefrontal cortex is less engaged during that task, allowing the basal ganglia to take over and free up cognitive resources.
Heuristics also aid in these processes by providing mental shortcuts that help in quick decision-making based on past experiences. The neural pathways formed through repetitious behavior become templates for future actions, creating a sort of muscle memory which allows us to perform tasks without active thinking, such as kicking a soccer ball or typing.
Research in neuroscience raises questions about the extent to which our actions are truly 'free' or rather predetermined responses by the brain. This interplay between conscious decision and unconscious habit formation is a deeply ingrained aspect of our biological makeup and has implications for our understanding of morality, ethics, and personal responsibility.