Hi Mariella,

I think they are different concepts. My understanding of it is that the mental lexicon is a much broader concept - it is a mental dictionary of words. It describes our representation of a word's meaning (semantics), pronunciation (phonological characteristics), syntax and morphology, etc. I get the impression that the mental lexicon is almost like a metaphorical representation of how our brain represents these things, and how they interact, but I think there is disagreement about how literal a concept this is: (http://www.sciencedirect.com/science/article/pii/S1364661304001366, this might help, or at the very least point you towards some useful articles in its references).

Semantic memory is then one component of this mental lexicon, one feature that is attached to words. 

I hope that helps, to an extent. I am not an expect in this field, but did work in it for a couple of years. Hopefully some other people will offer some insights as well! 

Hi, So what you mean is that mental lexicon is a broader concept while semantic memory is an aspect of it related to word meaning? I think I understand. Thank you very much for your help, your explanation has been very useful!

Hi Mariella,

Yes exactly, that is my interpretation of it. 

Mental lexicon is a much broader concept. Semantic memory is an aspect of the mental lexicon - the semantic meaning of words, as opposed to the other features. 

Glad it has helped somewhat! 

Mariella,

While the two terms of mental lexicon and semantic memory are largely synonymous (at least I think you can basically assume that for the process descriptions/ connections that you mention in your question), it might be helpful to appreciate that the two terms come from somewhat different perspectives within cognitive science - semantic memory is primarily memory research and mental lexicon is primarily psycholinguistics.

The term of semantic memory goes back to Tulving's (1972) (famous memory researcher) distinction from episodic memory, from the realization that while amnesia patients suffer problems with episodic memory (memories of their own lives - either lost past memories (retrograde amnesia) or problems to create new ones going forward (anterograde amnesia), they generally have intact semantic memory referring to general knowledge about the world, and including language.

In contrast, mental lexicon is often taken metaphorically as referring to one's mental dictionary (i.e., Jean Aitchison's  (2012). Words in the mind: An introduction to the mental lexicon (4th edition)).  I believe the term mental lexicon is somewhat preferable to mental dictionary, as lexicon has stronger sense of a more limited set of words, rather than dictionary implication of all words of native language.

From this metaphorical sense of mental lexicon as mental lexicon, there would also be some merit in metaphorically thinking of semantic memory as somewhat equating more to a mental encyclopedia.  That said, however, as with all metaphors there are limits as to how far one should take them.  For instance, in terms of the target mental phenomenon, I think it is fair to suggest that psycholinguists tending to recognize a greater variety of knowledge/information as influencing the organization of the mental lexicon, such as frequencies, abstract-concrete contrast, and so notion of traditional dictionary may be too restrictive.  On the one hand, as physical dictionaries (both print and electronic) become more inclusion of various kinds of information, the distinction between the dictionary and the encyclopedia can be rather blurred (especially in the age of Wikipedia).

I hope that these brief comments might be of some help for you in interpreting these terms and their various usages in the literature

There are models which distinguish between conceptual-semantic representations on the one hand and lexical representations on the other, the latter only representing word forms but no meaning. (e.g., Levelt, Roelofs & Meyer, 1999, Behavioral and Brain Sciences, or Coltheart, 2004, Quarterly Journal of Experimental Psychology)

@Terry Joyce: That is what I have been thinking. Essentially these two concepts are very closely related and even though they have been described in slightly different manners (in the literature you provided) it really depends on which standpoint you take. In my case, my standpoint is more neuropsychological in nature rather than psycholinguistic. Thank you for your help it is much appreciated.

Dear Mariella,

Here is my article concerning ideas about the way the words are stored in lexicon

Hope it will be of any help for you.

file:///G:/Песина%201/СТАТЬИ%202015/Дубай%20Global%202,%20Dec/PDF/Words%20Functioning%20in%20Lex%20Pesina,%20Yusupova.pdf

Conceptual representations are assumed to build an independent network

that is frequently referred to as semantic or conceptual memory (Levelt 1993).

It needs to be noted that semantic memory is not the same as the mental lexicon,

which is often compared to a dictionary. Rather, it is a mental encyclopedia independent of the formal linguistic representations of the lexical items (cf. Levelt

1993). Clark and Clark (1978) explain the distinction between the two by saying

that not all concepts stored in semantic memory have names in the mental lexicon.

A typical way of presenting conceptual representations of lexical items is a

rich network of sense relations. Semantic information is given meaning only by

the way it relates to other information. Putting it bluntly, “words are organized

in an interconnected system linked by logical relationships” (Aitchison 2003a,

p. 103). And thus, a definition of a word (concept) is always created in relation to

other words (concepts).

FROM (2 Modelling the Lexicon: Some General Considerations)