Use of numerical symbols by the chimpanzee (Pan troglodytes): Cardinals, ordinals, and the introduction of zero

An adult female chimpanzee with previous training in the use of Arabic numerals 1–9 was introduced to the meaning of "zero" in the context of three different numerical tasks. The first two were cardinal tasks where the subject was required either to select numerals corresponding to the number of items presented on a computer screen (productive use of numerals) or to match sets of the appropriate size to numerals presented as samples (receptive use). The third task addressed the ordinal meaning of the same symbols where the subject was required to respond to numerals sequentially, arranging them into an ascending series. The subject mastered the recognition of the meaning of zero in all three tasks. However, details of her usage of the symbol revealed that transfer of the meaning between different kinds of tasks was incomplete, suggesting that the level of abstraction characteristic of human numerical ability was not attained in the chimpanzee. Over the course of acquisition leading to the high levels of accuracy eventually observed, the newly introduced zero appeared to shift along the length of a continuous numerical scale toward the lower end, while confusions with 1 remained the most frequently encountered mistakes. Such patterns of error thus suggest that Ai's understanding of the meaning of zero in relation to the rest of the number symbols was not consistent with an "absence of items versus presence of items" scheme. Electronic Publication     

Bias in visual attention behavior in a normal school-aged population

Hemi-field visual-spatial attention was studied on a timed letter cancellation task in proficient readers from 7th to 9th grades. Participants maintained greater accuracy in identifying targets in the left quadrants (top/bottom) when compared with the right quadrants (top/bottom), revealing a leftward bias in their responses. Effects of gender and age were evident on performance; females scored significantly higher than males, and 9th graders scored significantly higher than 7th and 8th graders. Thus, a substantial shift in brain maturation may take place from 8th to 9th grades or from the ages of 13.0 to 14.11. Discriminative characteristics of the task are analyzed by assigning greater value to targets located in the top left quadrant. The 9th graders, as compared to the younger students, and the girls, as compared to the boys, evidenced a reading-direction-related bias toward systematic preference for the upper-left to lower-right quadrants.     

A pragmatic guideline for evaluation of social intervention

Considering the many theoretical and methodological viewpoints in the field of evaluation, a guideline was established to facilitate the evaluation of social intervention programs. For this purpose, the goals of the evaluation were taken into account: (a) planning interventions, (b) learning and continuous improvement of interventions, (c) programming policies, and (d) transformation of society. These goals will determine the perspective of the analysis selected (focusing on the evaluand or the context) and the strategies for change employed (focusing on processes or results). The elements that, according to Shadish, Cook, and Levinton (1991), constitute the theory of evaluation (evaluand, value, building of knowledge, and uses) have also been considered. The analysis of all these components led to the elaboration of a guideline to orient the practice of evaluation from a pragmatic perspective, in accordance with the demands and needs of a certain social context.     

On the relation between the acquisition of singular-plural morpho-syntax and the conceptual distinction between one and more than one

We investigated the relationship between the acquisition of singular-plural morpho-syntax and children's representation of the distinction between singular and plural sets. Experiment 1 tested 18-month-olds using the manual-search paradigm and found that, like 14-month-olds (Feigenson & Carey, 2005), they distinguished three objects from one but not four objects from one. Thus, they failed to represent four objects as 'plural' or 'more than one'. Experiment 2 found that children continued to fail at the 1 vs. 4 manual-search task at 20 months of age, even when told, via explicit morpho-syntactic singular-plural cues, that one or many balls are being hidden. However, 22- and 24-month-olds succeeded both with and without verbal cues. Parental report data indicated that most 22- and 24-month-olds, but few 20-month-olds, had begun producing plural nouns in their speech. Also, the success among the older children was due to those children who had reportedly begun producing plural nouns. We discuss a possible role for language acquisition in children's deployment of set-based quantification and the distinction between singular and plural sets.     

Latina Mothers’ Involvement in an HIV/STI and Substance Use Prevention Program for Adolescents: A Parallel Intervention Curriculum

As part of a larger HIV/STI/Substance Abuse Prevention intervention targeted to middle school students, we offered students’ parents an opportunity to participate in an adult education class. The same curricular materials were used for students enrolled in the intervention and for their parents. In the current study, mothers who had completed the adult education class participated in a focus group. The focus group explored what components of the intervention were perceived by mothers as particularly useful to them or to their child. Three core themes emerged from interpretive analyses of the focus group: (1) positive relationships with intervention staff and school personnel enticed students to participate in the intervention and facilitated parents’ involvement; (2) both students and parents felt respected and empowered by the intervention’s cornerstone values and curricular philosophy of cultural richness and pride in Hispanic/Latino heritage; and (3) mothers perceived their mastery of the course content—materially wholly dedicated to the health and wellness of their children—benefitted them in terms of both understanding the material and potentially allowing mothers to discuss health-oriented behavior with their young adolescent child.     

Bridging team faultlines by combining task role assignment and goal structure strategies

This study tests whether the detrimental effects of strong diversity faultlines on team performance can be counteracted by combining 2 managerial strategies: task role crosscutting and superordinate goals. We conducted a 2 (crosscut vs. aligned roles) × 2 (superordinate vs. subgroup goals) experimental study. Seventy-two 4-person teams with faultlines stemming from gender and educational major performed a complex decision-making task. The results show that teams with crosscut roles perform better when they are assigned a superordinate goal than a subgroup goal, whereas teams with aligned roles are not affected by goal manipulations. This effect is mediated by elaboration of task-relevant information. Implications for theory and management of team faultlines are discussed.