Chimpanzees prepare for alternative possible outcomes.

When facing uncertainty, humans often build mental models of alternative outcomes. Considering diverging scenarios allows agents to respond adaptively to different actual worlds by developing contingency plans (covering one's bases). In a pre-registered experiment, we tested whether chimpanzees (Pan troglodytes) prepare for two mutually exclusive possibilities. Chimpanzees could access two pieces of food, but only if they successfully protected them from a human competitor. In one condition, chimpanzees could be certain about which piece of food the human experimenter would attempt to steal. In a second condition, either one of the food rewards was a potential target of the competitor. We found that chimpanzees were significantly more likely to protect both pieces of food in the second relative to the first condition, raising the possibility that chimpanzees represent and prepare effectively for different possible worlds.

Toddlers learn and flexibly apply multiple possibilities.

The ability to consider multiple possibilities forms the basis for a wide variety of human-unique cognitive capacities. When does this skill develop? Previous studies have narrowly focused on children's ability to prepare for incompatible future outcomes. Here, we investigate this capacity in a causal learning context. Adults (N = 109) and 18- to 30-month olds (N = 104) observed evidence that was consistent with two hypotheses, each occupying a different level of abstraction (individual vs. relational causation). Results suggest that adults and toddlers identified multiple candidate causes for an effect, held these possibilities in mind, and flexibly applied the appropriate hypothesis to inform subsequent inferences. These findings challenge previous suggestions that the ability to consider multiple alternatives does not emerge until much later in development.

Transformations and Transfer: Preschool Children Understand Abstract Relations and Reason Analogically in a Causal Task.

Previous research suggests that preschoolers struggle with understanding abstract relations and with reasoning by analogy. Four experiments find, in contrast, that 3- and 4-year-olds (N = 168) are surprisingly adept at relational and analogical reasoning within a causal context. In earlier studies preschoolers routinely favored images that share thematic or perceptual commonalities with a target image (object matches) over choices that match the target along abstract relations (relational matches). The present studies embed such choice tasks within a cause-and-effect framework. Without causal framing, preschoolers strongly favor object matches, replicating the results of previous studies. But with causal framing, preschoolers succeed at analogical transfer (i.e., choose relational matches). These findings suggest that causal framing facilitates early analogical reasoning.

Young Children Are Wishful Thinkers: The Development of Wishful Thinking in 3- to 10-Year-Old Children.

Previously, research on wishful thinking has found that desires bias older children's and adults' predictions during probabilistic reasoning tasks. In this article, we explore wishful thinking in children aged 3- to 10-years-old. Do young children learn to be wishful thinkers? Or do they begin with a wishful thinking bias that is gradually overturned during development? Across five experiments, we compare low- and middle-income United States and Peruvian 3- to 10-year-old children (N = 682). Children were asked to make predictions during games of chance. Across experiments, preschool-aged children from all backgrounds consistently displayed a strong wishful thinking bias. However, the bias declined with age.

Learning what to change: Young children use "difference-making" to identify causally relevant variables.

Novel causal systems pose a problem of variable choice: How can a reasoner decide which variable is causally relevant? Which variable in the system should a learner manipulate to try to produce a desired, yet unfamiliar, casual outcome? In much causal reasoning research, participants learn how a particular set of preselected variables produce a particular effect. Here, we investigate 3- to 5-year-olds' ability to select the relevant variable for intervention in a novel causal system. Results demonstrate that even young children can learn which variable is causally relevant from sparse evidence. In particular, children infer that variables that are "difference-making" in one causal system will also be relevant to other, novel, causal problems. If manipulating a causal variable in a particular way leads to one effect, children assume that other manipulations of that variable will lead to other novel effects. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

When saying "I'm best" is benign: Developmental shifts in perceptions of boasting.

Four studies explored developmental changes in attitudes toward boasting. Overall, 5- to 7-year-olds (N = 130) were more likely than 8- to 11-year-olds (N = 126) and adults (N = 263) to view characters who boasted about valued traits as likable. In Study 1, younger children, unlike the older participants, liked and morally valued boasters who were accurate about their boasts. Justifications suggested the 5- to 7-year-olds perceived the boaster as sharing knowledge and being potentially helpful. No age group liked boasters who misrepresented themselves. In Study 2, boasters about valued traits were less liked by all ages than those who untruthfully downplayed their own abilities to please others. Adults, however, preferred boasters when the traits were unimportant and easily verifiable. In Study 3, a boaster was contrasted with a humble character, who never spoke about possessing the positively valued trait. Younger children showed a significant preference for the boaster, while older children and adults strongly preferred the humble person. Finally, Study 4 supported the proposal that younger children like boasters because boasters provide information about a capacity to help. Indeed, younger children valued boasters as potential helpers as much as they valued those who explicitly offered to help. Older participants did not differ from chance in their expectations that boasters could help. These age-related shifts in attitudes toward boasting may arise from a convergence of developmental changes in 4 underlying related processes-social sharing, self-presenting, discerning motives, and overoptimism. (PsycINFO Database Record

What Could You Really Learn on Your Own?: Understanding the Epistemic Limitations of Knowledge Acquisition.

Three studies explored the abilities of 205 children (5-11 years) and 74 adults (18-72 years) to distinguish directly versus indirectly acquired information in a scenario where an individual grew up in isolation from human culture. Directly acquired information is knowledge acquired through firsthand experience. Indirectly acquired information is knowledge that requires input from others. All children distinguished directly from indirectly acquired knowledge (Studies 1-3), even when the indirectly acquired knowledge was highly familiar (Study 2). All children also distinguished difficult-to-acquire direct knowledge from simple-to-acquire direct knowledge (Study 3). The major developmental change was the increasing ability to completely rule out indirect knowledge as possible for an isolated individual to acquire.

Searching for explanations: How the Internet inflates estimates of internal knowledge.

As the Internet has become a nearly ubiquitous resource for acquiring knowledge about the world, questions have arisen about its potential effects on cognition. Here we show that searching the Internet for explanatory knowledge creates an illusion whereby people mistake access to information for their own personal understanding of the information. Evidence from 9 experiments shows that searching for information online leads to an increase in self-assessed knowledge as people mistakenly think they have more knowledge "in the head," even seeing their own brains as more active as depicted by functional MRI (fMRI) images.