1. Neurological models explaining ”the concreteness effect” Christian Kastén 3. The context-availability model Its basic propositions are that: Abstract and concrete words are processed and represented by a common amodal semantic system which uses the same type of information code. There is neither a distinct verbal- nor a distinct image-based system. What determines the concreteness effect are the amount of contextual semantic features that can be associated with. While concrete words generally have more of these features abstract have less. In order to explain the effect of concreteness there is no need for a separate imagistic system which is architecturally more complex. When abstract words are presented with a relevant linguistic context or discourse the difference should be less noticable or disappear altogether and should be processed as efficiently as concrete words. This model could be interpreted as in favour of a holistic view where abstract and concrete words does not correspond to specific areas of the right and left hemispheres respectively. However you could also look at it as suggesting that the verbal system located in the left hemisphere has the dominant role because it provides the verbal context which according to this model is the only component necessary to explain concreteness. 4. A short discussion In support of the view of verbal- (abstract) and image-based (concrete) information being processed and stored by a common system it has been argued that pictures are remembered by semantic rather than purely visual features because visual information is somehow transformed into a semantic form for storage in long- term memory. Furthermore the claim that concreteness is reducible to the availability of context has been supported by some studies where abstract nouns are presented to a subject with a meaningful and sufficient amount of verbal context and is then processed as fast and as accurate as concrete nouns. In contrast evidence from studies of patients with right-brain lesions have shown that these performed significantly worse recalling previously displayed concrete nouns while such a difference did not occur for abstract nouns. This does indeed suggest the existence of a separate right-brain image-based system that corresponds specifically to concrete words. 1. The concreteness effect The concreteness effect is the observed phenomenon that concrete words are generally processed faster, with less errors and cause a greater degree of neural activity in more diverse areas (of both hemispheres) compared to abstract words. There are two dominant models that has been employed to explain the apparent differences between how concrete and abstract words are processed and represented in the brain; the dual-coding model and the context-availability model. There is experimental evidence supporting aspects of both these models, although the first one seems to be currently prevailing, and there is still an ongoing debate over their relative importance. Probably, in future a more complete explanation of the concreteness effect will contain ideas from both these theories. 2. The dual-coding model. This model proposes that: Abstract words are represented primarily/only as linguistic codes while concrete words are represented both as linguistic (non-imagery) and perceptual/imagistic (non-verbal) codes. When a concrete word is processed it activates and interconnects more diverse parts of the brain because both of these systems are involved, while abstract words are primarily/only processed by the linguistic system. Concrete words have significant processing advantages compared to abstract words because their dual types of semantic features gives access to multiple systems. This dualistic approach has been interpreted as supporting a more lateralized and localistic view of the division of labour between concrete and abstract because the right hemisphere is associated with imagery-based (concrete) semantic processing while the left with handling linguistic (abstract) information. References: Evidence for dual coding and context availability, F Jessen et al, The neural representation of concrete nouns…, Sophie K Scott Dual coding, context availability and concreteness…,Phillip J Holcomb et al