Cognitive Linguistics, a branch of study that most interests me, approaches language as a facet of general cognition, rather than as a separate linguistic module within the brain. From general cognitive capacities arise the human potential to talk. Our general cognitive ability of foregrounding/backgrounding (a white dot on a black surface, a train whistle on a rainy day) gives rise to cognitive linguistic notions figure/ground for the creation of words, such as ‘head‘, processing the head on a person as a linguistic figure perceived against the linguistic ground of the person as a whole with arms, torso, feet, and, in English, assigning the phonological/orhtographic string h e a d to this configuration. Figure/ground as a linguistic notion can be seen working at all levels of language, word, phrase, clause, sentence, discourse, and pragmatics.
The imagery that is required to process head in this way works from the same conceptual capacities that (re)casts the head on a beer as a metaphorical extension of the head on a person, meaning in this case, something similar to the very top portion attracting most attention. Images such as this arise from embodied cognition and as such, theories of language that integrate cognition with our intersubjective ability to talk, read, or write are simply superior to ones that study language as distinct modules in the brain, a phonology module, a semantics module, a syntax module, each module with their own distinct theoretical notions.
Here are some interesting links:
What is Cognitive Linguistics (a helpful book for purchase providing more details)
Glossary of Cognitive Linguistics (another helpful book for purchase defining terminology)
Other (an extensive list of resources for cognitive linguistics)