Spoken verb learning in children with language disorder.

The current study examined spoken verb learning in elementary school children with language disorder (LD). We aimed to replicate verb learning deficits reported in younger children with LD and to examine whether verb instrumentality, a semantic factor reflecting whether an action requires an instrument (e.g., "to chop" is an instrumental verb), influenced verb learning. The possible facilitating effect of orthographic cues presented during training was also evaluated. In an exploratory analysis, we investigated whether language and reading skills mediated verb learning performance. General language skills and verb learning were assessed in Dutch children with LD and age-matched typically developing controls (n = 25 per group) aged 8 to 12 years (M = 9;9 [years;months], SD = 1;3). Using video animations, children learned 20 nonwords depicting actions comprising 10 instrumental and 10 noninstrumental verbs. Half of the items were trained with orthographic information present. Verb learning was assessed using an animation-word matching and animation naming task. Linear mixed-effects models showed a main effect of group for all verb learning measures, demonstrating that children with LD learned fewer words and at a slower rate than the control group. No effect of verb instrumentality, presence of orthographic information, or the included mediators was found. Our results emphasize the importance of continued vocabulary instruction in elementary school to strengthen verb encoding. Given that our findings are inconsistent with the overall literature showing an orthographic facilitation effect, future studies should investigate whether participants pay attention to the written word form in learning contexts with moving stimuli.

Size, weight, and expectations.

The size-weight illusion is well-known: if two equally heavy objects differ in size, the large one feels lighter than the small one. Most explanations for this illusion assume that because the information about the relevant attribute (weight itself) is unreliable, information about an irrelevant but correlated attribute (size) is used as well. If such reasoning is correct, one would expect that the illusion can be inverted: if size information is unreliable, weight information will be used to judge size. We explored whether such a weight-size illusion exists by asking participants to lift Styrofoam balls that were coated with glow in the dark paint. The balls (2 sizes, 3 weights) were lifted using a pulley system in complete darkness at 2 distances. Participants reported the size using free magnitude estimation. The visual size information was indeed unreliable: balls that were presented at a 20% larger distance were judged 15% smaller. Nevertheless, the judgments of size were not systematically affected by the 20% weight change (differences < 0.5%). We conclude that because the weight-size illusion does not exist, the mechanism behind the size-weight illusion is specific for judging heaviness.