Can anyone help me, please?
In this context, “so that they [shoppers] buy products which their reasoning higher brain knows that they do not need or particularly want,” is “reasoning an Adjective or a Noun?
More likely an Adjective, but the Adjective of “reason” appears to be “reasonable”.
Reasoning is the present participle of the verb ‘to reason’. A participle may function as an adjective, describing or modifying a noun. The dancing parrots entertained the crowd. The seeing eye, the reasoning brain, the running man.