Is cognitive neuroscience an oxymoron? 1 Forthcoming: Current Controversies in Philosophy of Cognitive Science, Eds. S. Cullen, S.J. Leslie & A. Lerner Is cognitive neuroscience an oxymoron? Fiery Cushman 1. Introduction have a clear image in mind of just what “cognitive research” is. Cognitive theories Cognitive neuroscience research requires a attempt to describe the functional organization great deal of time and money, and it attracts a of the mind (Gallistel, 1990). The guiding great deal of attention. Consequently, there is a principle of the cognitive revolution is that we subversive temptation to declare it useless. This can understand how the mind processes general grumble comprises many related gripes: information. Specifically, we can characterize Cognitive neuroscience is poorly executed; its mental activity as a set of representations and costs do not justify its benefits; for a long time we computations over those representations. This all got along just fine without it, and I still do; it’s depends crucially upon an understanding of the just a fad; people are just wowed by pictures of function of the mental processes under study brains; etc. (Marr, 1982). Still, cognition is the study of mental compu- Some classic examples of psychological tations that are performed by a neural machine. research questions formulated in this framework It is remarkable to suppose that studying the are visual object recognition, language machine itself would not usefully inform production, and theory of mind. In the case of cognitive research. So which is it? Does visual object recognition, for instance, it is neuroscience illuminate cognitive research, or is assumed that the mind begins with a pixel-like it the moon that never rose? Is cognitive representation of the wavelengths and neuroscience an oxymoron? luminosities of light across the retina. It ends This essay dodges numerous gripes. It does with the capacity to categorize objects in the not address whether most cognitive neurosci- visual scene—e.g., categorizing one as a CAT and ence is well executed; whether its benefits another as HAT. This occurs as successive typically outweigh its costs; whether neurosci- computations are performed on the early ence could ever be necessary to develop a representation, transforming it over a series of psychological theory; or whether its celebrity representations. outstrips its merit. But it does conclude that This commitment to characterizing the neuroscience can play important role in internal representations that mediate between cognitive research. The argument has three percept and action is precisely why behaviorists parts: A general account of the relationship found the cognitive revolution so revolting. between neuroscience and cognition, a specific Behaviorism is committed, of course, to merely case study of the contribution of neuroscience to characterizing the relationship between a the study of visual cognition, and a quantitative stimulus and a response. This is a kind of analysis of citation records in the journal psychological theory. Indeed, it aptly describes Cognition. the kinds of theories of human behavior applied in some other disciplines. For instance, several 1.1 What is cognitive research? key principles of microeconomics do not attempt to mirror the representations or computations Before asking whether cognitive neurosci- involved in choice, except insofar as they ence contributes to cognitive research, it helps to appropriately characterize the relationship 1 Is cognitive neuroscience an oxymoron? 2 Forthcoming: Current Controversies in Philosophy of Cognitive Science, Eds. S. Cullen, S.J. Leslie & A. Lerner between input and output of a human chooser of theory they seek to advance, this would beg over time. Such theories achieve descriptive the question of whether neuroscience methods adequacy, in the sense that they accurately (e.g., cognitive neuroscience) can inform describe and predict human behavior (Chomsky, cognitive theory. The answer would be 1965). Cognitive theories, in contrast, guaranteed to be “no” for a trivial reason: Any additionally achieve explanatory adequacy. That study using apparent “neuroscience” methods to is, they aim to characterize the set of internal answer cognitive questions would simply have representations and computations that provide been “cognitive” research all along, by definition. an explanation for the reliability of descriptive relations between input and output. Thus, if 1.3 What is “important”? neuroscience plays an important role in cognitive research, it must do so by constraining theories What does it mean to say that neuroscience of representation and computation. has played, or could play, an “important” role in the development of cognitive theories? This 1.2 What is neuroscience? question is most interesting if it is reframed pragmatically: If we are interested in developing Neuroscience is the study of the nervous an accurate model of cognition, is it a useful system, including its physical and biological strategy to seek evidence from neuroscience properties. Like all cognitive theories, many methods? neuroscience theories are motivated by the Thus, neuroscience could be a useful source ultimate desire to explain the functional of evidence without being sufficient for the organization of the mind. Yet theories of development of cognitive theories. In other neuroscience can be distinguished from words, having a complete theory of cognition cognitive theories in part because they are stated may require us to know about more than just the over physical and biological terms (or explicit brain. A complete cognitive theory of visual abstractions from them) rather than over processing, for instance, might depend upon exclusively representational and computational information about typical scenes in natural terms. contexts (i.e., the things we see), as well as the Neuroscience comprises not only a set of functional role of vision in guiding human theories, but also a set of methods. A neurosci- interactions in the world. Whether cognitive ence method involves either manipulating or theories must be stated over terms external to measuring neural processes directly. In other the nervous system is a matter of significant words, it either involves an intervention upon philosophical controversy. But, even if we adopt neural processes in a manner that is not the position that a theory of mental representa- mediated by ordinary perception (e.g., neural tion and computation must be stated partially stimulation by electrical or magnetic forces, over terms external to the nervous system, the lesion by natural or artificial means, experi- neurosciences could still play a useful role in mental control of gene expression, etc.), or else it developing those theories. involves measuring neural processes in a manner Similarly, neuroscience could be a useful that is not mediated by ordinary behavior (e.g., source of evidence in developing cognitive EEG, MRI, single unit recording, etc.). In theories without being a definitive source of contrast, in “behavioral” methods, the evidence. (Indeed, it’s hard to say whether any experimenter’s access to mental processes is form of scientific evidence is ever definitive). mediated by ordinary perceptual and behavioral Presumably neuroscience will constrain processes. cognitive theories via inference to the best It is not necessary that neuroscience meth- explanation. That is, certain cognitive theories ods are used exclusively to inform neuroscience will provide a better explanation for the theories, or that behavioral methods are used neuroscience evidence, others will provide a exclusively to inform cognitive theories. This worse explanation, and we can use this to inform point is crucial: If we defined methods in terms our assessment of the quality of the cognitive 2 Is cognitive neuroscience an oxymoron? 3 Forthcoming: Current Controversies in Philosophy of Cognitive Science, Eds. S. Cullen, S.J. Leslie & A. Lerner theories. In this method of reasoning the For instance, there are detailed theories of the neuroscience evidence can play an important cellular mechanisms that enable neuronal firing; role in adjusting our assessment of the however, these are unlikely to be sufficiently probability of cognitive theories being correct, related to mental representation and computa- even without definitively endorsing or defeating tion to play an important role in cognitive any particular theory. research. Even if every cognitive representation Neuroscience could also be a useful source of is encoded by the firing of neurons, this does not evidence without being necessary for the mean that a theory of the mechanics of neural development of cognitive theories. This point is firing at the cellular level informs a theory of obvious enough. If I want to know what color cognitive representation. my socks are, looking at them would be a useful Consider a slightly different question, source of evidence, but it is certainly not a however: If a scholar wishes to understand the necessary source of evidence. I could buy a influence of Uncle Tom’s Cabin on American camera, hire a film crew to shoot a movie of my attitudes towards slavery, would it be useful for socks, show it to my wife and ask her what color her to read the book—i.e., to interact directly she sees. But even if it isn’t necessary for me to with it as a physical object? Presumably it look at my own socks to determine their color, it would, simply because this would provide could certainly be useful. relevant information about its contents, which Finally, it might be the case that neurosci- would in turn inform a theory of its influence. ence is a possible source of evidence without Reading the book might not be necessary. The being a practical one. For instance, the film- scholar could rely on indirect sources of crew approach is a possible method of attaining evidence about its content, and many of the evidence about the color of my socks, but it isn’t inferences she would wish to draw about its a very practical one. Although practicality is influence wouldn’t depend on knowing its important, I won’t address it much further. precise contents anyway.