Spatial reasoning in Tenejapan Mayans

Language communities differ in their stock of reference frames (coordinate systems for specifying locations and directions). English typically uses egocentrically-defined axes (e.g., “left–right”), especially when describing small-scale relationships. Other languages such as Tseltal Mayan prefer to use geocentrically-defined axes (e.g., “north–south”) and do not use any type of projective body-defined axes. It has been argued that the availability of specific frames of reference in language determines the availability or salience of the corresponding spatial concepts. In four experiments, we explored this hypothesis by testing Tseltal speakers’ spatial reasoning skills. Whereas most prior tasks in this domain were open-ended (allowing several correct solutions), the present tasks required a unique solution that favored adopting a frame-of-reference that was either congruent or incongruent with what is habitually lexicalized in the participants’ language. In these tasks, Tseltal speakers easily solved the language-incongruent problems, and performance was generally more robust for these than for the language-congruent problems that favored geocentrically-defined coordinates. We suggest that listeners’ probabilistic inferences when instruction is open to more than one interpretation account for why there are greater cross-linguistic differences in the solutions to open-ended spatial problems than to less ambiguous ones.     

Multiple victimization of Spanish adolescents: a multilevel analysis

Multiple victimization in adolescence is an issue that has received little research attention. Furthermore, adolescents are particularly vulnerable to victimization in different contexts. The aim of this study is to analyze correlates of multiple victimization in three contexts (home, school, and street). The following forms of victimization were considered: stealing, hitting, insulting, threatening, blackmailing, and weapon intimidation. Multiple victimization correlates explored were: sex, age, public/private school, socioeconomic status, quality of family relationships, and antisocial behavior. A probabilistic sample of 1,908 adolescents (ages 13 to 18) was used. Multilevel analyses were conducted to separate correlates at the individual level from those operating at the contextual level. Results show that gender, quality of family relationships, and deviant behavior were related to multiple victimization in adolescence.     

Conventionality in family conversations about everyday objects

Children's developing understanding that words have conventional meanings and objects have conventional functions emerges in parent-child activity and conversation. Drawing on family conversations in everyday settings, the chapter explores an apparent paradox between a global analysis of conventionality as stable shared knowledge and a local notion of conventions as flexibly negotiated in activity.     

The response ratio hypothesis for magnitude estimation

Assume that each presentation of a signal produces two independent random variable representations and that the ratio of responses on successive trials of a magnitude estimation experiment are proportional to the ratio of a representation from the present trial, which representation is then lost, to the remaining one from the previous trial. The mean response to a particular signal depends on the mean of the representation used, but in general exhibits drift over trials and sequential effects due to the preceeding trial; the mean response ratio does not exhibit drift, but it has a simple form only when there are no sequential effects; however, a modified mean ratio function has a simple form. A model suggested by D. V. Cross is a special case of this one. Simple timing and counting models for the representations fail to exhibit sequential effects, contrary to considerable data. However, data of the authors have suggested a version of the timing model in which the sample size of the representation varies by an order of magnitude depending on how close the signal is to the preceding one; this hypothesis accounts for the observed sequential effects and other aspects of the data.     

Effects of stimulus complexity on mental rotation rate of polygons

Both spatial and propositional theories of imagery predict that the rate at which mental images can be rotated is slower the more complex the stimulus. Four experiments (three published and one unpublished) testing that hypothesis found no effect of complexity on rotation rate. It is argued that despite continued methodological improvements, subjects in the conditions of greater complexity may have found it sufficient to rotate only partial images, thereby vitiating the prediction. The two experiments reported here are based on the idea of making the discriminative response sufficiently difficult so as to force the rotation of complete images. The first one scaled the similarity between standard polygons and certain systematically mutated versions. From the ratings so obtained, two levels of perceived similarity, high and low, were defined and served as separate conditions in a response-time, image rotation experiment. The second experiment tested the complexity hypothesis by examining the effect of similarity on rotation rates and its interaction with levels of complexity. The results support the complexity hypothesis, but only for the highly similar stimuli. Rotation times were also generally slower for high as compared with low similarity. It is argued that these results arise because subjects rotate incomplete images when the stimuli are not very similar.     

On how adults identify the orientation of a shape

It is generally assumed that the orientation of a shape is judged only by identifying the location of a particular feature. In contrast, it is argued here that the basis of orientation judgments depends on the task; this proposal is examined for judgments of upside down and sideways. Pictures of mono-oriented objects were presentedone at a time, and adults identified the orientations of each in a RT paradigm. One condition presented successively upright and upside-down pictures or upright and sideways pictures. Another condition presented successively upside-down and sideways pictures. As predicted, the time to identify orientation was longer for the condition presenting two nonuprights, because specific identifications of upside down and sideways were required, whereas the other condition required only that uprightness be distinguished from nonuprightness. The notion that the nature of a judgment of shape orientation depends on the contrasts provided by the task has implications for theory and experimental design that are discussed for both realistic and geometric shapes.