Lexical–semantic priming effects during infancy

When and how do infants develop a semantic system of words that are related to each other? We investigated word–word associations in early lexical development using an adaptation of the inter-modal preferential looking task where word pairs (as opposed to single target words) were used to direct infants’ attention towards a target picture. Two words (prime and target) were presented in quick succession after which infants were presented with a picture pair (target and distracter). Prime–target word pairs were either semantically and associatively related or unrelated; the targets were either named or unnamed. Experiment 1 demonstrated a lexical–semantic priming effect for 21-month olds but not for 18-month olds: unrelated prime words interfered with linguistic target identification for 21-month olds. Follow-up experiments confirmed the interfering effects of unrelated prime words and identified the existence of repetition priming effects as young as 18 months of age. The results of these experiments indicate that infants have begun to develop semantic–associative links between lexical items as early as 21 months of age.

The Detection and Identification of Pictorial Changes between Successive Presentations

The present research examines the abilitv to detect and identify particular changes between successive pictorial scenes. This investigation focussed on two particular types of change in complex black and white pictures: the addition of objects or patterns, or the deletion of similar objects or patterns in a successivly presented picture. In Experiment 1, additions were found to be more easilv identified than deletions but only for pattern changes and not for objects. This difference decreased in magnitude with a longer interval between pictures of a pair. A potential problem with this experiment is that subjects were required to report five changes per picture pair and systematic output competition effects may have interacted with picture memory as a function of delav. In Experiment 2 the picture pairs contained only one change. The results showed that additions were more often detected than deletions and object changes more often than pattern changes. A planned comparison revealed that the detection of pattern-additions were significantly better than the detection of pattern-deletions. Experiment 3 again replicated this finding. The results of this research are discussed in terms of a dual-code theory and its utility in a variety of applied settings.

Preschool Children's Performance with Perceptual and Conceptual Recognition Criteria

In two picture recognition experiments preschool children were required to make three different recognition decisions to a single study picture. In both experiments one of the three tests was based on perceptual identity (level 1), one on common objectclass (level 2), and the third on either taxonomic category or complementary pair formation (level 3). In experiment 1 it was found that the preschool children (X age = 4-10) could make both level 3 recognition decisions with equal ease and at 90% accuracy although there was a significant decline in performance as level of abstraction increased. In experiment 2, three-, four-, and five-year-olds' recognition accuracy improved with age and decreased as level of abstraction increased. Category decisions were associated with lower accuracy levels than those based on complementary pairs. For the category pairs, inferior choice explanations lagged well behind accuracy and improved with age in contrast with the acceptable explanations given by all age groups for the complementary pair solutions. Commonalities in the children's perceptions of the two level 3 grouping principles were discussed, as was the possible confounding of the comparison of the two organizational principles by differential picture pair difficulty.