Methodological-conceptual problems in the study of chimpanzees’ folk physics: How studies with adult humans can help

Abstract

In three experiments, we examined humans' folk physics (i.e., a naturally occurring and spontaneous understanding of the physical world), using variations of problems used to study chimpanzees' folk physics. Presented with trap-tube problems in two experiments, adult humans showed an unnecessary bias to insert a stick into the end of the tube farthest from the reward to push it out the other end. When presented with trap-table problems with ineffective trapping holes, people unnecessarily avoided the side with the hole. The similarity of humans' and chimpanzees' behavior on these tasks highlights methodological and conceptual problems in studies of chimpanzees' folk physics and suggests alternative explanations for their behavior.

The development of tool manufacture in humans: what helps young children make innovative tools?

“…Tool innovation has performed a vital role in the evolution of our own species, and by studying children whose ability to innovate is still developing, we can gain insights into the psychological processes supporting it. This has important implications for understanding these processes in humans, but also means that our baseline assumptions about what constitutes 'human-level performance' in non-human animals may not be accurate [39,73,74].…”

Task-specific modulation of adult humans’ tool preferences: number of choices and size of the problem

“…In Experiment 1, the mean length of this stick was longer than in the previous studies. The length of the stick used to drag the object 16 cm was more similar to A general implication of these results is that they highlight the importance of the task, in terms of both its causal structure and its nonfunctional features, in the study of physical cognition (see Silva et al, 2005;Silva & Silva, 2006;Tecwyn et al, 2012). Despite the fact that we can be reasonably certain that adult humans' physical cognition consists of an intuitive understanding of constructs such as "gravity" and "transfer of force," and that the causal structure and dimensions of the problem used in Experiment 1 were identical to those used previously to study people's folk physics (e.g., Silva & Silva, 2010), modifying a single stick to an ideal length produced different results from selecting a stick from a set of ten.…”

“…The results of these experiments illustrate that the specific features of the task used to study physical cognition cannot be overlooked or devalued; people are sensitive to more than the casual structure of the task. Changing these nonfunctional features changes people's behavior, even when their folk physics or understanding of the problem may be unchanged (see also Silva et al, 2005;Silva & Silva, 2006).…”

“…These constructs-cognitive effort, usability, and margin of safety-and related variables, processes, and rules may be why adult humans' tool selections differ from those of crows on similar tasks. In short, people's and other animals' behavior on tool-use tasks may be due to things (e.g., features of the task, associative learning, or procedural rules) other than simply the causal structure of a task and a subject's understanding of physical causality (Silva, Page, & Silva, 2005;Silva & Silva, 2006;Tecwyn, Thorpe, & Chappell, 2012).…”

“…Our general goal was to collect information about how these features affect the expression of people's physical cognition, which in turn may help interpret nonhumans' behavior on similar tasks or suggest future experiments with nonhuman subjects (e.g., Hachiga, Silberberg, Parker, & Sakagami, 2009;Silberberg et al, 2013;Silva et al, 2005;Silva & Silva, 2006).…”