Tuesday, July 01, 2008

Discontinuity between human and nonhuman minds?

In a recent issue of Brain and Behavioral Science (BBS) Penn, Holyoak and Povinelli argue for a profound difference in kind, not degree, between human and animal minds. Their suggestions elicit mainly vigorous opposition as well as some support from an array of commentators. Several of the commentators point out evidence for flexible relational capabilities within a physical symbol system exhibited by dolphins and birds. As I read through the debate and its mind-numbing detail I give up on trying to convey a succinct summary, but here is their abstract. (You might compare this with the work of Hauser et al, that I mentioned in a previous post.):
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.


  1. I read this paper (one of the co-authors was my instructor last semester). I tend to think that the debate is not really all that constructive. Besides, very early in the paper, the authors basically say in a footnote something like: "Well of course there's a continuum of cognitive skills. We're just arguing that it's a discontinuous-looking continuum."

    What is constructive about the paper is the critical review of many of the claims made in the animal cognition literature, and a stark look at what faculties we can confidently attribute to non-human animals. I think they're spot-on in that critique.

  2. There is no doubt that these guys are full of shit, but a fundamental problem in determining how human cognition arose is figuring out how our extinct ancestors thought. Putting chimpanzees and bonobos through the wringer can only tell us so much, since there is virtually no way to communicate with the precision of language with nonhuman apes.

    Therein also lies the problem in the quest to get many people to realize that we're animals too.