Impetus beliefs as default heuristics: Dissociation between explicit and implicit knowledge about motion

Abstract

We examined the extent to which findings from the literature on naive physics and representational momentum studies are consistent with impetus beliefs postulating imparted internal energy as a source of motion. In a literature review, we showed that, for situations in which impetus theory and physical principles make different predictions, representationalmomentum effects are consistent with impetus beliefs. In three new experiments, we examined people's implicit and explicit knowledge of the effect of mass on the rate of ascending motion. The results suggest that implicit knowledge is consistent with impetus theory and is unaffected by explicit knowledge. Expert physicists, whose explicit knowledge is in accord with Newtonian principles, exhibited the same implicit impetus beliefs as novices when asked to respond in a representational momentum paradigm. We propose that, in situations in which an immediate response is required and one does not have specific contextual knowledge about an object's motion, both physics experts and novices apply impetus principles as a default heuristic.

Different Physical Intuitions Exist Between Tasks, Not Domains

“…This contrasts with the theory of Kozhevnikov and Hegarty (2001) who suggest that Bimplicitk nowledge of physics is erroneous but could be corrected by explicit knowledge, and the theory of Zago and Lacquaniti (2005), who propose that that perceptual physics knowledge is biased but our motor predictions use calibrated physics. The theories suggesting biased Bimplicit^physics have been based on evidence from the Brepresentational momentum^lit-erature that memory for the location of objects is shifted based on the dynamics of impetus physics rather than Newtonian mechanics (e.g., if two objects are moving downward on the screen then disappear, people will remember the larger object as having Bfallen^further than the smaller object; Hubbard 1997).…”

“…However, our findings are not captured by this framework either. First, Kozhevnikov and Hegarty (2001) find that implicit knowledge is erroneous and explicit knowledge can correct these misconceptions, whereas we find more accurate physical principles from the system that would map onto the Bintuitive^beliefs. Second, both the catching and releasing trials were not immediate-they took a few seconds to resolve each-and yet we found no evidence that any of our participants were systematically using the same information they used on the drawing task.…”

“…However, the pendulums observed in the drawing task of Experiment 2 were identical to the pendulums of the catching and releasing tasks of Experiment 1, and so in this case, it was only a difference of response modality and not stimulus realism that drove the difference in behavior. Kozhevnikov and Hegarty (2001) suggest that when people must make immediate responses they rely on default, implicit beliefs, but when they have a chance to reflect, they can override these intuitions with explicit, verbalizable knowledge. However, our findings are not captured by this framework either.…”

“…3). 2 In addition, Kozhevnikov and Hegarty (2001) suggest that people use impetus physics as their default implicit beliefs about physical events. Although no participants displayed beliefs of impetus physics in our drawing task (and only 11% of participants did so in Caramazza et al 1981), we aimed to test whether an impetus model might capture participants' responses on the interactive tasks better than a calibrated physics model or other non-physical models.…”

Explanation and Understanding

“…For example, people frequently prefer one explanation to another without explicitly being able to say why. They often seem to draw on implicit explanatory understandings that are not easy to put in explicit terms (Kozhevnikov & Hegarty 2001). Even without strictly adhering to the deductivenomological model of explanations, some explanations in domains such as biology hardly invoke laws at all (Bechtel & Abrahamsen 2005).…”