Developmental changes in the visual, haptic, and bimodal perception of geometric angles.

Geometrical knowledge is typically taught to children through a combination of vision and repetitive drawing (i.e. haptics), yet our understanding of how different spatial senses contribute to geometric perception during childhood is poor. Studies of line orientation suggest a dominant role of vision affecting the calibration of haptics during development; however, the associated multisensory interactions underpinning angle perception are unknown. Here we examined visual, haptic, and bimodal perception of angles across three age groups of children: 6 to 8 years, 8 to 10 years, and 10 to 12 years, with age categories also representing their class (grade) in primary school. All participants first learned an angular shape, presented dynamically, in one of three sensory tracing conditions: visual only, haptic only, or bimodal exploration. At test, which was visual only, participants selected a target angle from four possible alternatives with distractor angle sizes varying relative to the target angle size. We found a clear improvement in accuracy of angle perception with development for all learning modalities. Angle perception in the youngest group was equally poor (but above chance) for all modalities; however, for the two older child groups, visual learning was better than haptics. Haptic perception did not improve to the level of vision with age (even in a comparison adult group), and we found no specific benefit for bimodal learning over visual learning in any age group, including adults. Our results support a developmental increment in both spatial accuracy and precision in all modalities, which was greater in vision than in haptics, and are consistent with previous accounts of cross-sensory calibration in the perception of geometric forms.

Outcomes of Healthy Eating Ad Campaigns: A Systematic Review.

Social marketing campaigns seeking to promote healthy eating hold promise in precision messaging and behavior change related to a key component of healthy living medicine. A systematic review that examines the behaviors promoted against their success is lacking. Of interest is the consideration of stop or go behaviors, such as not eating fast food or increasing the consumption of fruits and vegetables, respectively. We systematically searched five databases for peer-reviewed quantitative articles examining healthy eating campaigns that included at least one ad. We found evidence that campaigns with both stop and go outcomes (such as swapping) and outcomes that were not clarifying whether they were stop or go (such as calling a coach) tended to be more successful than campaigns with simple stop or go outcomes. Further, campaigns that were longer than six months seemed consistently successful. However, with 14 included studies, it is clear that further research is needed.

Self-reported patterns of health services utilisation: an urban-rural comparison in South Australia.

OBJECTIVE: To compare self-reported patterns of health service utilisation among residents of urban and rural South Australia. DESIGN, SETTING AND MAIN OUTCOME MEASURES: Secondary analysis of data generated by computer-assisted telephone interviews of 7377 adults done in 1995-6. Respondents were asked if they had used each of 18 different health services during the previous 12 months. Residence was classified in three ways: (1) capital city versus rest of the state, (2) by the Rural, Remote and Metropolitan Areas classification (RRMA) and (3) by the Accessibility and Remoteness Index for Australia classification (ARIA). RESULTS: General practitioner services were most frequently used, by approximately 89% of respondents. Only 4% reported not using any service. Comparing capital city with rest of the state, modest but statistically significant differences in utilisation (P < 0.01) were measured for nine services. In eight of these nine, utilisation was higher among rural residents. Analysing by RRMA, eight services were reportedly used differently and seven of these were the same as those identified from the capital city versus rest of state comparison. Across the five ARIA categories, six previously identified services were reported as being used differentially. Overall, rural residents had a higher than expected rate of moderate and high level of health service use. CONCLUSIONS: Self-reported use of a range of health services was broadly similar across urban and rural South Australia, with most cases of higher use were reported from rural areas rather than urban areas. Similar results were obtained when residence was classified in the three different ways.

Increased tooth crown size in females with twin brothers: Evidence for hormonal diffusion between human twins in utero.

In rodents, the position of a fetus in utero is associated with the expression of sexually dimorphic traits. This phenomenon has been explained by prenatal diffusion of sex hormones among litter mates. To test for such effects in humans, female-male twin pairs provide a natural experiment. The size of dental crowns is a sexually dimorphic trait which can be measured with a high degree of reliability. Thus, two crown diameters of 28 permanent teeth were recorded for 56 opposite-sexed (OS) and 242 same-sexed (SS) twin pairs, and 150 singletons. Comparisons of OS twins with SS twins and singletons within each sex reveal that OS females have consistently larger teeth (on average) than other females, while there is no consistent difference between OS and SS twin males. It is proposed that diffusion of sex hormones from male to female co-twins in utero may account for the increased tooth size in OS females. This study is one of the first to report such an effect on a morphological variable in humans. The finding that the maxillary canine, one of the most sexually dimorphic teeth, exhibits the least effect in OS female twins, suggests that prenatal sex hormone levels may have less impact on sexual dimorphism in the maxillary canines than in other permanent teeth. Am. J. Hum. Biol. 11:577-586, 1999. Copyright 1999 Wiley-Liss, Inc.