Planning is an important component of cognition that contributes, for example, to efficient movement through space. In the current study we presented novel two-dimensional alley mazes to four chimpanzees and three capuchin monkeys to identify the nature and efficiency of planning in relation to varying task parameters. All the subjects solved more mazes without error than expected by chance, providing compelling evidence that both species planned their choices in some manner. The probability of making a correct choice on mazes designed to be more demanding and presented later in the testing series was higher than on earlier, simpler mazes (chimpanzees), or unchanged (capuchin monkeys), suggesting microdevelopment of strategic choice. Structural properties of the mazes affected both species' choices. Capuchin monkeys were less likely than chimpanzees to take a correct path that initially led away from the goal but that eventually led to the goal. Chimpanzees were more likely to make an error by passing a correct path than by turning onto a wrong path. Chimpanzees and one capuchin made more errors on choices farther in sequence from the goal. Each species corrected errors before running into the end of an alley in approximately 40% of cases. Together, these findings suggest nascent planning abilities in each species, and the prospect for significant development of strategic planning capabilities on tasks presenting multiple simultaneous or sequential spatial relations. The computerized maze paradigm appears well suited to investigate movement planning and spatial perception in human and nonhuman primates alike.

The authors investigated strategies used to combine seriated cups by apes (Pan troglodytes and P. paniscus) and monkeys (Cebus apella) using a protocol reported in P. M. Greenfield, K. Nelson, and E. Saltzman's (1972) study with children. It was hypothesized that apes would exhibit more hierarchical combinations of cups than monkeys, given apes' language capacity, and that apes would seriate the cups more efficiently than monkeys. As predicted, apes made many structures with the cups using a variety of strategies, and monkeys rarely combined the cups. After a training phase to orient monkeys to the task, the 2 genera did not differ in the strategies used to combine the cups or in efficiency in seriating the cups. Success in this task suggests that sensorimotor versions of hierarchically organized combinatorial activity are well within apes' and monkeys' abilities.

We examined whether navigation is impacted by experience in two species of nonhuman primates. Five chimpanzees (Pan troglodytes) and seven capuchin monkeys (Cebus apella) navigated a cursor, using a joystick, through two-dimensional mazes presented on a computer monitor. Subjects completed 192 mazes, each one time. Each maze contained one to five choices, and in up to three of these choices, the correct path required moving the cursor away from the Euclidean direction toward the goal. Some subjects completed these mazes in a random order (Random group); others in a fixed order by ascending number of choices and ascending number of turns away from goal (Ordered group). Chimpanzees in both groups performed equivalently, demonstrated fewer errors and a higher rate of self-correcting errors with increasing experience at solving the mazes, and made significantly fewer errors than capuchin monkeys. Capuchins were more sensitive to the mode of presentation than chimpanzees: Monkeys in the Ordered group made fewer errors than monkeys in the Random group. However, capuchins’ performance across testing changed little, and they remained particularly susceptible to making errors when the correct path required moving away from the goal. Thus, these two species responded differently to the same spatial challenges and same learning contexts. The findings indicate that chimpanzees have a strong advantage in this task compared to capuchins, no matter how the task is presented. We suggest that differences between the species in the dynamic organization of attention and motor processes contribute to their differences in performance on this task, and predict similar differences in other tasks requiring, as this one does, sustained attention to a dynamic visual display and self-produced movements variably towards and away from a goal.

Positive intercultural attitudes and civic action are increasingly important for youth around the world given the economic, social justice, and environmental challenges they face. Among U.S. youth and emerging adults, ethnic identity and self-efficacy are related to positive intercultural attitudes and may prompt civic engagement. Youth’s efficacy and civic involvement are critically important in sub-Saharan Africa, where rates of civil conflict are among the highest in the world. However, little research has been conducted with East African youth. In this paper, we discuss contextual challenges facing East African youth and the potential role of ethnic identity and self-efficacy in promoting peaceful and sustainable societies. We report qualitative results and scores on standard measures of self -efficacy, ethnic identity, and intercultural attitudes for 554 youth members of environmental clubs in Tanzania, Uganda, and the United States. Ethnic identity was associated with enhanced self-efficacy in East African, but not U.S. participants. East Africans scored higher on ethnic identity compared to U.S. youth and were more likely to reference intercultural attitudes in open-ended responses. Results provide some support for construct relevance in East Africa, however psychometric results, including internal consistency, validity, and factor structure, were mixed. Our results provide a cautionary tale about the import of measures across cultures and contexts. There is a need for international research, measurement development, and further explication of the meaning and function of ethnic identity across cultures.

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China is a key player on the global stage, and nearly 300 million Chinese youth stand to be affected by rapid social and ecological transformations. Programs that promote developmental assets in Chinese youth could increase their resilience in the face of contemporary stressors and enhance their capacity to contribute to China's development. In this paper we describe a unique, service-learning approach to youth development, the Jane Goodall Institute's Roots & Shoots program (R&S), as it is implemented in China. Through qualitative and quantitative methods we explore perceptions of program impact on the personal and social development of Chinese youth. Cultural, sociopolitical, and environmental issues related to program practices, outcomes and viability are highlighted. Results suggest that R&S mobilized Chinese youth to work for the benefit of their environment, their communities, and themselves.

The performance of 4-and 5-year-old children and rhesus monkeys was compared using a computerized task for quantity assessment. Participants first learned two quantity anchor values and then responded to intermediate values by classifying them as either similar to the large anchor or the small anchor. Of primary interest was an assessment of where the point of subjective equality (PSE) occurred for each species across four different sets of anchors to determine whether the PSE occurred at the arithmetic mean or the geometric mean. Both species produced PSEs that were closer to the geometric mean for three of four anchor sets. This indicates that monkeys and children access either a logarithmic scale for quantity representation or a linear scale that is subject to scalar variability, both of which are consistent with Weber's law and representation of quantity that takes the form of analog magnitudes. KeywordsQuantity Judgments; Representational Scale; Children; Monkeys; Bisection TaskThe quantity discriminations made by many species are restricted in their accuracy on the basis of the ratio between those sets (e.g., Barth, Kanwisher, & Spelke, 2003;Beran, 2007;Beran, Taglialatela, Flemming, James, & Washburn, 2006;Brannon, Cantlon, & Terrace, 2006;Brannon & Terrace, 2000;Call, 2000;Huntley-Fenner, 2001). Comparisons with larger ratios (as determined by dividing the smaller quantity by the larger quantity) lead to lower performance levels, even when the distance between sets is constant (e.g., 8 versus 10 is more difficult than 2 versus 4). This suggests that an analog magnitude system produces discriminable representations of sets, and this system is consistent with Weber's law, which states that discrimination of sets becomes more difficult for a fixed difference as the magnitude of those sets increases.Correspondence to: Michael Beran, Language Research Center, Georgia State University, University Plaza, Atlanta, GA 30303, Telephone -404-244-2469, Fax -404-244-5829, E-mail -mjberan@yahoo.com. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Evidence for discrimination performance being modulated by Weber's Law comes from differing sources. One task, used primarily with nonhuman primates, involves judgments between two sets of items (e.g., Beran, 2004;Brannon & Terrace, 2000;Call, 2000; Judge, Evans, & Vias, 2005). This task also sometimes is used with human children (e.g., Brannon & Van de Walle, 2001; Feigenson, Carey, & Hauser, 2003). The second task is the bisection task that has been used extensively with rats and pigeons (e.g., Emmerton & Renner, 2006;Fetterm...

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