Lanquage and Memory

Memory and Language

Semantic memory is part of a larger division of memory known as declarative memory which refers to items in memory that can be consciously retrieved or recalled such as factual information, memories of events, and other types of knowledge (Tulving, 1972). Semantic memory is the memory of meanings and concept-based knowledge that can be consciously recollected such as facts about the world, word meanings, and other related information, whereas the other component of declarative memory, episodic memory, refers to the memory of biographical and event-related information (Tulving, 1972). Semantic memory functions as a storehouse of knowledge that can be consciously retrieved and applied when needed in specific situations and comprises a large amount of what we learn about the world and out relations in it (Tulving, 1972). Semantic memories are language based.

Human language is a different form of communication that used by other species of animals. Other species of animals have communications of sorts, but is not the same as human language. For example certain monkeys have distinct warning calls for different types of threats, but they do not combine these calls to express completely novel ideas. Human language is a system of verbal (or gestural) communication that allows for a veritable limitless number of ideas to be expressed by combining a finite set of verbal (or gestural) elements (Wargo, 2008). Thus, the function of human language is to provide for communication but also for expression and understanding of complex ideas.

The Russian linguist Roman Jakobson described six basic functions of language: (1) referential, describes a situation, mental state, or object; (2) expressive or emotive, self-expression; (3) conative, addressing the receiver; (4) poetic, focusing on the message for its own sake; (5) phatic, language for the sake of interacting with others, and; metalingual or reflexive, language used to describe itself (Jakobson, 1963).

According to Bock and Levelt language production consists of four stages: (1) conceptualization, thinking and deciding what it is a person wishes to communicate or express; (2) formulation of this desire into a linguistic plan; (3) the execution of the plan by the muscles used for speech production and; (4) monitoring speech production making sure it is what was intended to be expressed in the manner intended. The Wernicke-Geschwind model of language production was based on observations of language impairments in brain-damaged individuals and illustrates how this process works: Suppose one is having a conversation. The auditory signals from the speech of the other person are received by the primary auditory cortex in the brain and relayed to Wernicke's area in the brain (left temporal lobe) where it is comprehended. Wernicke's area generates the neural representation of the reply and transmits this intended reply by way of a tract of neuron fibers known as the left arcuate fasciculus to the posterior portion of the frontal lobe of the brain. Here the neural representation is activated in Broca's area and this activates an articulation program that is transmitted to the appropriate neurons in the primary motor cortex that control the muscles of language articulation of the face. The primary motor cortex send this message to these muscles and the response is articulated (Poeppel & Hickok, 2004). While the Wernicke -- Geschwind model has been popular for many years, with the advent of neuroimaging it is been discovered that multiple areas of the brain are activated during language production and not just the areas in this particular model. Moreover, patients with certain types of aphasia can have variable damage in the brain not specifically in these language production and language reception areas identified by the model (Poeppel & Hickok, 2004). Nonetheless, this model of language comprehension and language expression remains popular.

One interesting proposition regarding the Wernicke-Geschwind model is the notion of mentalese. Psycholinguists have proposed that some form of mentalese, a mental representation system different from language but that is translated into linguistic form in the brain, exists. However, there is little evidence or agreement as to the properties of this form of pre-linguistic mental representation (Dudai, 2007; Poeppel & Hickok, 2004).