Impaired development of semantic memory: Separating semantic from structural knowledge and diagnosing a role for action in establishing stored memories for objects
Humphreys GW., Riddoch MJ.
We report a single case study of the recognition abilities present in a child (JS) with balanced translocation of chromosomes 2 and 6, who also suffered birth trauma and long-standing epilepsy. We show that, despite intact early visual processes, there is a recognition deficit for objects contingent on poor acquisition of associative semantic, but not perceptual, knowledge. This deficit is particularly pronounced for objects that are low in familiarity and whose names are usually acquired later. The effect is also influenced strongly by the familiarity of the viewpoint from which objects are depicted. The impairment is consistent across items over time (over and above effects due to familiarity and age of acquisition). Nevertheless, there are positive effects of phonemic cueing, particularly for living things. There are additionally positive effects on name learning of pairing objects with actions, at the time of name acquisition. We discuss the results in relation to models of adult object recognition and naming, and argue that deficits in development provide a useful means for studying the different forms of stored representation mediating recognition.