Young children’s perception of diagrammatic representations

Diagrams and pictorial representations are common in children's lives and require abstraction away from visual perception. In three experiments, we investigated 4- to 8- year-olds’ comprehension of such representations. In Experiment 1 (N = 80), children were shown photographs of geometric objects and asked to choose the corresponding line drawing from among sets of four, or vice versa. Results showed considerable developmental progression, especially around age 6. Experiment 2 (N = 16) ruled out that 4-year-olds’ difficulties were due to problems with the visual matching task itself. Experiment 3 (N = 32) showed comparable performance for matching diagrams to 3D objects rather than to photographs. Findings suggest increasing understanding of diagrammatic representations around the time of school entry

Methods of Hatching Eggs of the Blue Crab

The blue crab, Callinectes sapidus Rathbun, is the only important marketable crustacean in Chesapeake Bay. While this body of water may be regarded as a center of its numerical distribution, blue crabs in the United States range from Cape Cod south to Texas. Their economic importance is indicated by records of the Federal Government which report for the four-year period 1936-39, an annual average of over 82 million hard crabs valued at about $526,000 from Virginia and 56 million worth about$382,000 from Maryland. Soft crab catches in the two states during this period were approximately the same, amounting in each case to over 10 million crabs per year valued at about $210,000. The commercial value of this fishery, shared by Maryland and Virginia, to local tidewater communities warrants careful examination of the economic and production trends in their relation to sound conservation practice. In view of the need for information on the early development of the blue crab, studies were begun at the Virginia Fisheries Laboratory in 1940. An effort was made to develop a hatching technic for crab eggs under laboratory conditions that might open the way for large scale application under natural conditions. During the summer of 1941, the crab work was extended and intensified in view of reports of a serious shortage of soft crabs, particularly in Maryland. Aiming to answer questions of practical value to the industry and to crab conservation, studies on the hatching of eggs and experiments on water conditions as they affect hatching and survival of crab larvae were stressed

Learning across business sectors: knowledge sharing between aerospace and construction

This report addresses the extent that managerial practices can be shared between the aerospace and construction sectors. Current recipes for learning from other industries tend to be oversimplistic and often fail to recognise the embedded and contextual nature of managerial knowledge. Knowledge sharing between business sectors is best understood as an essential source of innovation. The process of comparison challenges assumptions and better equips managers to cope with future change. Comparisons between the aerospace and construction sectors are especially useful because they are so different. The two sectors differ hugely in terms of their institutional context, structure and technological intensity. The aerospace sector has experienced extensive consolidation and is dominated by a small number of global companies. Aerospace companies operate within complex networks of global interdependency such that collaborative working is a commercial imperative. In contrast, the construction sector remains highly fragmented and is characterised by a continued reliance on small firms. The vast majority of construction firms compete within localised markets that are too often characterised by opportunistic behaviour. Comparing construction to aerospace highlights the unique characteristics of both sectors and helps explain how managerial practices are mediated by context. Detailed comparisons between the two sectors are made in a range of areas and guidance is provided for the implementation of knowledge sharing strategies within and across organisations. The commonly accepted notion of ‘best practice’ is exposed as a myth. Indeed, universal models of best practice can be detrimental to performance by deflecting from the need to adapt continuously to changing circumstances. Competitiveness in the construction sector too often rests on efficiency in managing contracts, with a particular emphasis on the allocation of risk. Innovation in construction tends to be problem-driven and is rarely shared from project to project. In aerospace, the dominant model of competitiveness means that firms have little choice other than to invest in continuous innovation, despite difficult trading conditions. Research and development (R&D) expenditure in aerospace continues to rise as a percentage of turnovers. A sustained capacity for innovation within the aerospace sector depends crucially upon stability and continuity of work. In the construction sector, the emergence of the ‘hollowed-out’ firm has undermined the industry’s capacity for innovation. Integrated procurement contexts such as prime contracting in construction potentially provide a more supportive climate for an innovation-based model of competitiveness. However, investment in new ways of working depends upon a shift in thinking not only amongst construction contractors, but also amongst the industry’s major clients

Development of mental transformation abilities

Mental representation and transformation of spatial information is often examined with mental rotation tasks, which require deciding whether a rotated image is the same or the mirror version of an upright image. Recent research with infants shows early discrimination of objects from mirror image versions. However, even at age 4, many children perform near chance level on more standard measures. Similar age discrepancies can be observed in other domains, including perspective taking, theory of mind, and intuitive physics. These paradoxical results raise the questions of how performance relates to competence, and how to conceptualize developmental change. There may be a common underlying mechanism: the development of the ability to imagine things and mentally transform them in a prospective fashion

Zooming in on spatial scaling: Preschool children and adults use mental transformations to scale spaces

Spatial scaling is an important prerequisite for many spatial tasks and involves an understanding of how distances in different-sized spaces correspond. Previous studies have found evidence for such an understanding in preschoolers; however, the mental processes involved remain unclear. The present study investigated whether children and adults use mental transformations to scale distances in space. Adults and 4- and 5-year-old children (N = 60) were asked to use maps to locate target objects in a larger referent space on a touchscreen. The size of the referent space was held constant, but the sizes of the maps were varied systematically, resulting in seven scaling factors. A linear increase in response times and errors with increasing scaling factor suggested that participants of every age group mentally transformed the size of the map to compare it to the referent, providing evidence for an analog imagery strategy in children’s and adults’ spatial scaling

Using mental transformation strategies for spatial scaling: Evidence from a discrimination task

Spatial scaling, or an understanding of how distances in different-sized spaces relate to each other, is fundamental for many spatial tasks and relevant for success in numerous professions. Previous research has suggested that adults use mental transformation strategies to mentally scale spatial input, as indicated by linear increases in response times and accuracies with larger scaling magnitudes. However, prior research has not accounted for possible difficulties in encoding spatial information within smaller spaces. Thus, the present study used a discrimination task in which we systematically pitted absolute size of the spaces against scaling magnitude. Adults (N = 48) were presented with 2 pictures, side-by-side on a computer display, each of which contained a target. Adults were asked to decide whether the targets were in the same position or not, by pressing the respective computer key. In the constant-large condition, the constant space was kept large, whereas the size of the other space was variable and smaller. In the constant-small condition, the constant space was small, whereas the size of the other space was variable and larger. Irrespective of condition, adults’ discrimination performance (d- primes) and response times were linear functions of scaling magnitude, supporting the notion that analog imagery strategies are used in spatial scaling

Using a touch screen paradigm to assess the development of mental rotation between 3½ and 5½ years of age

Mental rotation is an important spatial skill. However, there is controversy concerning its early development and susceptibility to intervention. In the present study, we assessed individual differences in the mental rotation abilities of children between 3½ and 5½ years of age, using a touch screen paradigm to simplify task demands. A figure or its mirror image was presented in 8 different orientations, and children indicated in which of two holes the figure would fit by touching one of the holes on the screen. Task instructions were varied in three conditions, giving the children the opportunity to gather manual or observational experience with rotations of different stimuli, or giving no additional experience. Children’s error rates and response times increased linearly with increasing angular disparity between the figure and the hole by the age of 5 years, but 4-year-olds were found to respond at chance for all angular disparities, despite the use of a touch screen paradigm. Both manual and observational experience increased the response accuracy of 5-year-olds, especially for children already performing well. However, there was no effect on 4-year-olds. Results point to an emerging readiness to use mental rotation and profit from observational and manual experience at age 5

Reorienting with terrain slope and landmarks

Orientation (or reorientation) is the first step in navigation, because establishing a spatial frame of reference is essential for a sense of location and heading direction. Recent research on nonhuman animals has revealed that the vertical component of an environment provides an important source of spatial information, in both terrestrial and aquatic settings. Nonetheless, humans show large individual and sex differences in the ability to use terrain slope for reorientation. To understand why some participants—mainly women—exhibit a difficulty with slope, we tested reorientation in a richer environment than had been used previously, including both a tilted floor and a set of distinct objects that could be used as landmarks. This environment allowed for the use of two different strategies for solving the task, one based on directional cues (slope gradient) and one based on positional cues (landmarks). Overall, rather than using both cues, participants tended to focus on just one. Although men and women did not differ significantly in their encoding of or reliance on the two strategies, men showed greater confidence in solving the reorientation task. These facts suggest that one possible cause of the female difficulty with slope might be a generally lower spatial confidence during reorientation

Development of mental rotation in 3- to 5-year-old children

We assessed 3- to 5-year-olds’ mental rotation abilities using a new puzzle paradigm. It allows for assessment of mental rotation abilities in children younger than 5 years, using a task comparable to ones used with older children and adults. Children saw pairs of asymmetrical ghost figures, either as three-dimensional cut-outs or two- dimensional paper versions, in seven orientations. One of the ghosts fit into a hole if rotated right-side up – the other ghost was its mirror image and would not fit. Children were asked to turn the ghosts in their heads and choose the one that would fit into the hole. The number of children who chose the correct ghost above chance in the three- dimensional version of the task increased dramatically from 10% of 3-year-olds to 95% of 5-year-olds; average accuracy also increased significantly, from 54% to 83%. The two-dimensional paper version yielded similar results. These results indicate considerable development in mental rotation between 3 and 5 years