Chris Donlan

What makes counting count? Verbal and visuo-spatial contributions to typical and atypical number development.

Williams Syndrome (WS) is marked by a relative strength in verbal cognition coupled with a serious impairment in non-verbal cognition. A strong deficit in numerical cognition has been anecdotally reported in this disorder; however, its nature has not been systematically investigated. Here, we tested 14 children with WS (mean age=7 years 2 months), 14 typically developing controls individually matched on visuo-spatial ability (mean age=3 years 5 months) as well as a larger group of typically developing controls (mean age=3 years 4 months) on two tasks to assess their understanding that counting determines the exact quantity of sets (cardinality principle). The understanding of the cardinality principle in children with WS is extremely delayed and only at the level predicted by their visuo-spatial MA. In this clinical group, only language accounted for a significant amount of the variance in cardinality understanding, whereas in the normal comparison group only visuo-spatial competence predicted the variance. The present findings suggest that visuo-spatial ability plays a greater role than language ability in the actual development of cardinality understanding in typically developing children, whereas the opposite obtains for the clinical group.

Number Skills and Knowledge in Children With Specific Language Impairment

The number skills of groups of 7- to 9-year-old children with specific language impairment (SLI) attending mainstream or special schools were compared with an age and nonverbal reasoning matched group (age control [AC]) and with a younger group matched on oral language comprehension. The SLI groups performed below the AC group on every skill. They also showed lower working memory functioning and had received lower levels of instruction. Nonverbal reasoning, working memory functioning, language comprehension, and instruction accounted for individual variation in number skills to differing extents depending on the skill. These factors did not explain the differences between SLI and AC groups on most skills.

The role of syntax in encoding and recall of pictorial narratives: Evidence from specific language impairment

Previous research on typically developing children has shown that their memory for events depends on how they are encoded. As children grow older, they start to mention causal and temporal relationships between events, including psychological causes. Children with specific language impairment (SLI) were studied to disentangle the effects of syntactic skill and non-verbal IQ on event encoding and recall. Children with receptive SLI (SLI-R; N = 34) had a significant discrepancy between non-verbal IQ and scores on a receptive language measure. Those with expressive SLI (SLI-E; N = 29) did not have significant receptive impairment, but had low scores on at least one expressive language test. Controls were 32 typically developing children of similar age and non-verbal IQ. Children were shown two sequences of photographs, and in each case, were asked first to describe the story, and then, without warning, to recall it after a delay of 30-40 minutes. Compared with controls, children with SLI recalled significantly less story material. For the SLI-E group, poor recall was totally accounted for by poor initial encoding of the story content. However, for the SLI-R group, story memory was poor even after adjusting for amount of information in the initial narrative. Description and recall of the story ideas were related to use of complex syntax, and failure to use cognitive state terms predicted poor recall. We conclude that use of complex syntax and causal concepts are more important than non-verbal IQ in determining childrens event memory.

Children's Comprehension of Unfamiliar Regional Accents: A Preliminary Investigation.

The effect of regional accent on childrens processing of speech is a theoretically and practically important aspect of phonological development that has been little researched. 48 children from London, aged four and seven years old, were tested on their ability to repeat and define single words presented in their own accent and in a Glaswegian accent. Results showed that word comprehension was significantly reduced in the Glaswegian condition and that four-year-olds performed less successfully than seven-year-olds. Both groups made similar numbers of lexical misidentifications, but the younger children were more likely to fail to access any word at all. On the repetition task, the younger children showed a different pattern of errors to the older children, their productions being apparently more influenced by the phonetics of the Glaswegian stimuli. It is suggested that such phonetic responses are related to the younger childrens failure to map the unfamiliar accent onto their own phonological representations. It is proposed that the lexical misidentifications, common to both age groups, are more likely to be induced by lack of context. The paper concludes with discussion of implications of these findings for our understanding of how children develop the ability to process unfamiliar regional accents.

Typical and atypical development of visual estimation abilities.

Despite the fact that developmental impairments of number skills are common, they remain sparsely investigated. We explored low-level numerical representations and their developmental trajectory in a developmental disorder, Williams syndrome (WS). Groups of WS and typically developing (TD) individuals estimated rapidly-presented arrays of 5, 7, 9, and 11 dots. In comparison to the normal developmental trajectory, the ontogenesis of estimation skills in WS is both delayed and deviant. Whereas TD childrens estimations became significantly more accurate and less variable over developmental time, only marginal developmental changes in estimation ability emerged across age in the WS groups. Our data highlight the importance of considering developmental changes in low-level components of numerical cognition in atypical development while at the same time emphasizing the importance of paying closer attention to quantitative changes and their functional role in typical development.

Effects of death within 11 years on cognitive performance in old age

Six different cognitive tests and the Heck Depression Inventory (BDI) were given to 3,572 active community residents aged 49 to 93 years. Causes of death were ascertained for 443 who died between 36 and 3,903 days later. Subsequent survival predicted test scores during the 3,903 days and independently during Days 36 to 1,826 and Days 1,827 to 3,903. Scores on the BDI and cumulative verbal learning and vocabulary tests predicted mortality after demographics and performance on other cognitive tests had been considered. Predictors were similar for deaths from heart disease, malignancies, and other causes. A new finding that cognitive tests did not predict survival duration within the sample of deceased explains previous findings of greater terminal decline in performance for young than for elderly adults.

Grammatical morphology as a source of early number word meanings

Significance Languages vary in how they grammatically mark number (e.g., in nouns, verbs, and so forth). We test the effects of this variability on learning number words—for example, one, two, three—by investigating children learning Slovenian and Saudi Arabic, which have singular-plural marking, but also dual marking (for sets of two). We find that learning the dual is associated with faster learning of the meaning of two than in any previously studied language, even when accompanied by less experience with counting. We conclude that although exposure to counting is important to learning number word meanings, hearing number words used outside of these routines—in the quantificational structures of language—may also be highly important in early acquisition. How does cross-linguistic variation in linguistic structure affect children’s acquisition of early number word meanings? We tested this question by investigating number word learning in two unrelated languages that feature a tripartite singular-dual-plural distinction: Slovenian and Saudi Arabic. We found that learning dual morphology affects children’s acquisition of the number word two in both languages, relative to English. Children who knew the meaning of two were surprisingly frequent in the dual languages, relative to English. Furthermore, Slovenian children were faster to learn two than children learning English, despite being less-competent counters. Finally, in both Slovenian and Saudi Arabic, comprehension of the dual was correlated with knowledge of two and higher number words.

The importance of non-verbal skills in the acquisition of place-value knowledge: Evidence from normally-developing and language-impaired children

Childrens comprehension of the Hindu-Arabic number system was explored in relation to their ability to match spoken to Hindu-Arabic numerals. The possible involvement of verbal processes in numeric understanding was examined by comparing a group of 8-year olds with specific language impairments (SLI group, N = 13) to two control groups, the first matched for age and non-verbal ability (AC group, N = 13), the second younger group matched for language comprehension level (LC group, N = 12). SLI, AC and LC childrens accuracy and efficiency in choosing the greater of two single-digit Hindu-Arabic numerals were compared. One child from the SLI group and three from the LC group failed to reach accuracy criterion. For accurate responders there was no difference between SLI and AC groups in latency to judge: both responded faster than the LC group. When making judgments all groups showed the Symbolic Distance Effect observed by Moyer & Landauer (1967). All participants were able to match spoken numerals to Hindu-Arabic single-digit numerals without error. SLI and AC groups were tested on double digits. Accuracy and efficiency in judging the greater of two Hindu-Arabic double-digit numerals were tested. Ability to match spoken numerals to corresponding double-digit Hindu-Arabic numerals was also tested. All of 12 AC participants accurately matched spoken to Hindu-Arabic symbols, but 2 of these were unable to judge accurately the greater of pairs of HinduArabic symbols. Of 13 SLI children tested, 9 accurately matched spoken to Hindu-Arabic symbols; 2 of these were unable to judge Hindu-Arabic symbols accurately. One further child was able to judge accurately but performed poorly when matching spoken to Hindu-Arabic numerals. When school experience of doubledigit numbers was statistically controlled, there was no difference between SLI and AC groups in the accuracy of double-digit judgments. No difference was found between SLI and AC groups in the speed or pattern of accurate responders’ doubledigit judgments. When group data was pooled and school experience statistically controlled, accuracy in double-digit judgment was predicted by non-verbal ability, but not by expressive or receptive language skills. The pattern of responses to the double-digit judgments suggested a ‘holistic’ processing mechanism within which ‘transparent’ stimuli (those double digits which minimize conflict between ‘face’ and ‘place’ values) are most rapidly encoded. Whereas the ability to match verbal labels to Hindu-Arabic numerals appears generally to precede single- and double-digit comprehension, findings suggest that, especially in the acquisition of place-value knowledge, there is substantial autonomy of non-verbal systems.

Stuttering severity, psychosocial impact and lexical diversity as predictors of outcome for treatment of stuttering.

OBJECTIVE This study assessed factors that predicted therapy outcome for children and adolescents who stuttered after attendance at an intensive therapy course. The factors examined were stuttering severity, lexical diversity measured by Type Token Ratio, and psychosocial impact of stuttering on the childs life. DESIGN Fifty-four children who stuttered (CWS) participated in the study. The hypotheses were: (1) CWS with high initial stuttering severity would be more likely to persist than those with low initial severity; (2) lexical diversity before treatment should be related to therapy outcome; (3) psychosocial factors would affect therapy outcome. The predictions were assessed by linear and logistic regression analyses. RESULTS Initial stuttering severity was the only significant predictor for stuttering severity after therapy. However, psychosocial impact correlated with improvement in fluency, and lexical diversity correlated with therapy outcome. CONCLUSIONS Only initial stuttering severity was a significant predictor of therapy outcome after an intensive therapy intervention. This is in agreement with the study of Howell and Davis (2011). EDUCATIONAL OBJECTIVES Readers will get an overview of the literature on risk factors that are considered to predict therapy outcomes for CWS. They will be able to (a) identify what variable represent potential risk factors, (b) describe the psychosocial impact of stuttering, (c) explain how lexical diversity is measured, and (d) describe different assessment instruments used to decide on the outcome of therapy.

Deductive reasoning in children with specific language impairment

The diagnosis of specific language impairment (SLI) requires non-verbal ability to be in the normal range, but little is known regarding the extent to which general reasoning skills are preserved during development. A total of 122 children were tested; 40 SLI, 42 age-matched controls, and 40 younger language-matched controls. Deductive reasoning tasks were given in both verbal and pictorial presentation types, namely the relational inference task and the reduced array selection task (RAST). Pictorial presentation facilitated all groups for all tasks equally. For the relational inference task, SLI performance was below both age and language matches. For the RAST, contextual information facilitated all groups equally. SLI performance was intermediate between age and language matches. It is concluded that the non-verbal versus verbal distinction is a complex one and that non-verbal reasoning can draw upon linguistic processes. It is also suggested that SLI reasoning depends upon precise task demands, here the need to sequence information in working memory, and the need for explicit reasoning with conditional rules. Reasoning processes may not be equivalent to normally developing children, even when tasks appear non-verbal.