The development of category learning strategies: What makes the difference?

Category learning can be achieved by identifying common features among category members, distinctive features among non-members, or both. These processes are psychologically and computationally distinct, and may have implications for the acquisition of categories at different hierarchical levels. The present study examines an account of children’s difficulty in acquiring categories at the subordinate level grounded on these distinct comparison processes. Adults and children performed category learning tasks in which they were exposed either to pairs of objects from the same novel category or pairs of objects from different categories. The objects were designed so that for each category learning task, two features determined category membership whereas two other features were task irrelevant. In the learning stage participants compared pairs of objects noted to be either from the same category or from different categories. Object pairs were chosen so that the objective amount of information provided to the participants was identical in the two learning conditions. We found that when presented only with object pairs noted to be from the same category, young children (6 ? YO ? 9.5) learned the novel categories just as well as older children (10 ? YO ? 14) and adults. However, when presented only with object pairs known to be from different categories, unlike older children and adults, young children failed to learn the novel categories. We discuss cognitive and computational factors that may give rise to this comparison bias, as well as its expected outcomes.     

the role of dimensional distinctiveness in children's and adults' artifact categorization

There are conflicting results as to whether preschool children categorize artifacts on the basis of physical or functional similarity. The present study investigated the effect of the relative distinctiveness of these dimensions in children's categorization. In a physical-distinctive condition, preschool children and adults were initially asked to categorize computer-animated artifacts whose physical appearances were more distinctive than their functions. In a function-distinctive condition, the functional dimension of objects was more distinctive than their physical appearances. Both conditions included a second stage of categorization in which both dimensions were equally distinctive. Participants in a control condition performed only this stage of categorization. Adults in all conditions and stages consistently categorized by functional similarity. In contrast, children's categorization was affected by the relative distinctiveness of the dimensions. Children may not have a priori specific beliefs about how to categorize novel artifacts, and thus may be more susceptible to contextual factors.     

How writing system and age influence spatial representations of actions: a developmental, cross-linguistic study

Recently, researchers reported a bias for placing agents predominantly on the left side of pictures. Both hemispheric specialization and cultural preferences have been hypothesized to be the origin of this bias. To evaluate these hypotheses, we conducted a study with participants exposed to different reading and writing systems: Germans, who use a left-to-right system, and Israelis, who use a right-to-left system. In addition, we manipulated the degree of exposure to the writing systems by testing preschoolers and adults. Participants heard agent-first or recipient-first sentences and were asked to draw the content of the sentences or to arrange transparencies of protagonists and objects such that their arrangement depicted the sentences. Although preschool-age children in both countries showed no directional bias, adults manifested a bias that was consistent with the writing system of their language. These results support the cultural hypothesis regarding the origin of spatial-representational biases.     

Analysis of the US-preexposure effect in flavor acceptance conditioning

In three experiments, rats received exposure to a sucrose solution followed by conditioning with a neutral flavor as the conditioned stimulus (CS) and sucrose as the unconditioned stimulus (US). In Experiments 1 and 2, some rats were given both the preexposure and the conditioning phases in a highly familiar context (the homecage), whereas other animals received both phases in a novel and distinctive context. In both cases the magnitude of the conditioning effect was reduced by preexposure to the US. Experiment 3 directly assessed the possible role of contextual cues by changing the context between the exposure phase and the conditioning phase but found no loss of the US-preexposure effect in these conditions. These results lend no support to the blocking-by-context account of the US-preexposure effect; alternative interpretations are considered.     

Time perception in response to ashamed faces in children and adults

The present study investigated the effect of the perception of faces expressing shame on time perception in children aged 5 and 8 years, as well as in adults, as a function of their ability to recognize this emotional expression. The participants' ability to recognize the expression of shame among faces expressing different emotions was tested. They were then asked to perform a temporal bisection task involving both neutral and ashamed faces. The results showed that, from the age of 8 years, the participants who recognized the facial expressions of shame underestimated their presentation time compared to that of neutral faces. In contrast, no time distortion was observed in the children who did not recognize the ashamed faces or in those younger children who did recognize them. The results are discussed in terms of self-conscious emotions which develop to involve an attentional mechanism.     

Discrimination and Reversal Learning by Toddlers Aged 15-23 Months

Few studies have investigated simple discrimination and discrimination reversal learning by children younger than 2 years. Extant research has shown that teaching discrimination reversals may be challenging with this population. We used social reinforcement and correction procedures to teach simple simultaneous discrimination and discrimination reversal tasks involving three pairs of animal pictures displayed in a paper notebook. Participants were eight typically developing toddlers aged 15-23 months. All learned at least one simple discrimination/discrimination reversal problem. Four children learned all problems and showed evidence of learning set formation. Perhaps surprisingly, discrimination reversals were sometimes learned more rapidly than original discriminations. The procedures suggest a potentially efficient methodology for investigating more complex aspects of relational learning in toddlers.

     

Crossing borders and demolishing boundaries: the connected history of the Israeli transgender community 1953–1986

ABSTRACT

This is the first study to examine the early history of the Israeli transgender community. It covers three decades of transgender activity, from Rina Nathan’s public campaign in the 1950s to permit gender confirmation surgeries in the country to the decision in 1986 to allow surgeries in one public hospital after a lengthy vetting process that de facto held up or disqualified the great majority of applications. The main focus of this study is the generation of “founding mothers” of the transgender community in the 1960s and 1970s and their quest to obtain knowledge, medical technology and paperwork necessary for their gender journeys. We argue that decades before the creation of the internet, Israeli trans pioneers crossed domestic and international boundaries (both social and spatial) and created a network, which later generations of transgender women and men would depend on. This article relies on oral history, contemporaneous media reports and archival documents.