Darwin's mistake: Explaining the discontinuity between human and nonhuman minds

Abstract

Over the last quarter century, the dominant tendency in comparative cognitive psychology has been to emphasize the similarities between human and nonhuman minds and to downplay the differences as "one of degree and not of kind" (Darwin 1871). In the present target article, we argue that Darwin was mistaken: the profound biological continuity between human and nonhuman animals masks an equally profound discontinuity between human and nonhuman minds. To wit, there is a significant discontinuity in the degree to which human and nonhuman animals are able to approximate the higher-order, systematic, relational capabilities of a physical symbol system (PSS) (Newell 1980). We show that this symbolic-relational discontinuity pervades nearly every domain of cognition and runs much deeper than even the spectacular scaffolding provided by language or culture alone can explain. We propose a representational-level specification as to where human and nonhuman animals' abilities to approximate a PSS are similar and where they differ. We conclude by suggesting that recent symbolic-connectionist models of cognition shed new light on the mechanisms that underlie the gap between human and nonhuman minds.

The discovery and comparison of symbolic magnitudes

“…In addition to supporting generalization to new animal pairs, these explicit relations can be systematically transformed to solve analogies based on higher-order relations between different pairs of polar adjectives (e.g., larger: smaller:: faster: slower). However, such highlevel reasoning is beyond the capability of most animals (indeed, it may be uniquely human; Penn, Holyoak, & Povinelli, 2008). In contrast, basic comparative judgment appears to be similar in humans and symbol-trained monkeys (Diester & Nieder, 2010;Moyer & Landauer, 1967).…”

“…As Penn et al (2008) argued based on a review of comparative studies, there is overwhelming evidence that many species of animals can make relational judgments based on perceptual information, yet no compelling evidence that any non-human primate is able to reason about relations. At the same time, it appears that the neural system supporting comparisons based on approximate magnitude in non-human primates operates in humans as well (Dehaene & Changeux, 1993).…”

Analogical and category-based inference: A theoretical integration with Bayesian causal models.

“…Why? The answer, which calls for advances in the theoretical integration of causal models with analogical inference, may provide a major clue as to why the inductive power of human reasoning exceeds that of any other form of biological or artificial intelligence (Holland et al, 1986;Penn, Holyoak, & Povinelli, 2008). 3b.…”

Dynamic Coordination in Brain and Mind

“…An important issue is therefore whether metacognitive processes, such as analogies, syntax, and thoughts about thoughts, require dynamically embedded groupings (Hummel and Holyoak 2005). If so, some phylogenetic and ontogenetic differences may be due to the evolution and development of that specific capacity (Penn, Holyoak, and Povinelli 2008). The neuronal dynamics that could embody any such capability are yet to be discovered.…”