The rational mind: What is it?
"People are smart." That's how a corporate commercial tries to flatter
those who would take advantage of its services. There's certainly no
disputing humans' ability to profit by experience and to engage in
adaptive behavior. There's also no disputing that we are also prone to
repeat our errors and to engage in maladaptive behavior. So, how smart
are we really? Are we truly endowed with a rational mind, what René
Descartes called the "universal instrument?"
To many theorists,
the rational mind is a thing or process that: (a) guides sensible or
logical action, (b) avoids emotion or bias in judgment, (c) maximizes
some good or function, and (d) produces universally optimal results (see
Kahneman, 2003 for further elaboration).
A survey of discussions about the rational mind suggests that this idea
can be approached from many different angles. My own approach is
comparative. It asks: Is the rational mind peculiarly human (see Hurley
& Nudds, 2006 for more on rationality in animals)?
A seed for a comparative approach can be gleaned from the words of
Wilford O. Cross. In his 1964 Prologue to Ethics, Cross wrote that, "The
rational mind of man is a shallow thing, a shore upon a continent of
the irrational, wherein thin colonies of reason have settled amid a
savage world."
If signs of the rational mind are so unlikely to be seen in a
notoriously savage world, then we must ask, "Why?" One answer is that
humans and animals have adapted to highly complex and constantly
changing environments by deploying behavioral and cognitive processes of
a decidedly mechanical sort. These mechanical processes of adaptation
are usually, but not always effective; critically, they need not be
rational.
Reason Amid a Savage World
The notion that mechanical processes might join with rational processes
in producing adaptive action is far from new. Indeed, it was advanced by
the Greek philosophers Plato, Aristotle, and Galen, and it was
advocated by the French philosopher René Descartes.
Plato hypothesized an appetitive soul (emotion or desire), a spirited
soul (will or volition), and a rational soul (mind or intellect). The
rational soul was believed to be exclusively human; Plato likened it to a
"charioteer" who adeptly controls his appetitive and spirited "steeds."
Aristotle hypothesized a nutritive soul (characteristic of plants,
animals, and humans), a sensitive soul (characteristic of animals and
humans), and a rational soul (characteristic of humans alone and
residing in the heart). Galen hypothesized a vegetative soul (in the
liver), an animal soul (in the heart), and a rational soul (in the
brain).
Descartes famously distinguished the involuntary, unconscious, and
unlearned reflexes of the body from the rational soul of the mind. Both
humans and animals display mindless, reflexive action; but only humans
exhibit mindful, rational behavior which is voluntary, conscious, and
learned in the lifetime of an individual. Descartes believed that human
mind and body converge in the pineal gland.
Integrating these related notions, we see that the idea of the rational
mind has been prominent in Western thought for nearly 2,500 years. Both
humans and animals are impelled by biological forces to survive and
procreate. Many behaviors of humans and animals promote these aims. But
only humans are rational: we alone are capable of using our minds to
make prudent decisions that maximize the ends of proper living.
In empirically evaluating the claim that the rational mind is uniquely
human, I will focus on two out of many possible illustrative realms
primarily because of my familiarity with them: concept learning and
causal judgment. I will also explore whether we need the notion of the
rational mind to explain either kind of cognition--in animals or humans.
And, I will end by commenting on the prospects of a scientific account
of behavior, whether or not we deem the behavior in question to be
rational.
Concepts
Concepts epitomize rationality; they are highly efficient cognitive
devices or shortcuts that reduce the taxing demands that a complex and
changing world places on an organism's limited information processing
and storage systems. As well, concepts are universal and effectively
control behaviors to new stimuli in new settings. And concepts may be
uniquely human--at least, so contended the English philosopher John
Locke. "The having of general Ideas, is that which puts a perfect
distinction betwixt Man and Brutes…. For brutes have not the faculty of
abstracting, or making general Ideas" (1690, pp. 159-160).
Of many different kinds of concepts, one will concern us here: natural
kind concepts (often and perhaps more aptly called "basic-level"
concepts, because human made things are similarly classified).
Basic-level concepts (e.g., tree and axe) are not simply conventional
and contrived for mere convenience, but real. To use Plato's words, they
"cut nature at its joints."
My specific questions concerning concept learning are these: Do animals
too learn basic-level concepts? Must reason be invoked to explain this
brand of conceptualization?
Basic-level concepts are easy to learn, even by young children
(Wasserman & Rovee-Collier, 2001). They take very little time for
both adults and children to report. And, they are based on physical
similarity-at least, so claimed American philosopher and mathematician
W. V. Quine.
According to Quine, both humans and animals possess an innate standard
of similarity; that standard is absolutely animal in its lack of
intellectual status. Critically, Quine believed that similarity is the
bedrock of basic-level categories.
Of course, humans readily learn and use basic-level concepts. But, what
about nonhuman animals? To answer this question, researchers in my
laboratory (Bhatt, Wasserman, Reynolds, & Knauss, 1988) endeavored
to teach pigeons a four-alternative forced-choice "naming" task, where
pecks replaced words as arbitrary report responses. After having been
shown a color photograph of a cat, a car, a chair, or a flower, hungry
pigeons had to correctly peck one of four different report keys; food
was given after correct reports, whereas no food and one or more
correction trials were given after incorrect reports.
The pigeons did, in fact, promptly learn to correctly report these four
basic-level concepts by pecking four different report keys in the
presence of the different classes of photos, with ten or more different
photos in each of the classes. Furthermore, the pigeons reliably
generalized this discrimination to new photos of objects from the four
classes, showing that these categories were effectively open-ended.
What evidence supports the idea that this conceptual discrimination
learning is actually based on an "innate standard" of similarity? First,
pigeons learn the just-described discrimination that "cuts nature at
its joints" far faster than they learn an otherwise similar
discrimination involving the same stimuli that does not (Wasserman,
Kiedinger, & Bhatt, 1988). An example of the latter kind of
discrimination is one in which equal numbers of photos from each of the
four classes are arbitrarily placed into four "pseudocategories;" such
pseudocategories lack any "perceptual glue" to bind together members of
the different groupings. Second, confusion errors in an altogether
different kind of discrimination task (Astley & Wasserman, 1992)
unequivocally demonstrate that pigeons do indeed see discriminably
different members of a basic-level human language category, like
flowers, to be more similar to one another than to members of other
categories, like people, cars, or chairs.
It is therefore wholly unnecessary to appeal to reason in order to
explain basic-level concept learning. Rather, perceptually homogeneous
stimuli are simply associated with arbitrary responses: words for people
and pecks for pigeons. Those discriminative responses transfer to new
stimuli within the same perceptual classes-a textbook case of what
behavior theorists have for a century called primary stimulus
generalization.
Causation
Causation exemplifies rationality. Ascertaining true natural causes can
help guide sensible or logical action without the intrusion of emotion
or bias as well as help maximize important goods or functions in any and
all circumstances. Causal judgment is fundamental to natural science.
Identifying and verifying causal relations between natural phenomena
would appear to demand sophisticated logical or statistical thinking.
Such highly advanced thinking should surely be uniquely human. Right?
"Wrong," answered the Scottish philosopher David Hume.
According to Hume, utterly mechanical associative processes lead to the
impression of causation, which lies not in the environment, but in the
mind of the beholder. Furthermore, Hume believed that the same
associative processes operate in humans and animals. Why? Because
survival in an inherently dangerous world cannot possibly depend on the
slowness, deliberateness, and elaborateness of formal logic and
deductive reason. The phrase "lost in thought" does indeed have two
dramatically different meanings!
My specific questions concerning causal judgment are these: Are there
clear empirical parallels between associative learning in animals and
causal judgment in people? Must reason be invoked to explain human
causal judgment? Can a different sort of theoretical account embrace
both associative learning in animals and causal judgment in people?
Hume offered several seminal insights into the psychology of causal
judgment. First, causal beliefs arise from the association of ideas.
Because that association emerges from the frequent conjunction of
events, causal beliefs must ascend to their peak by degrees. So, like
associative learning curves, causal judgments should emerge gradually.
Second, causal beliefs cannot produce assurance in any single event as
the cause unless it proves to be superior to rival causes. So, as in the
case of the familiar phenomenon of associative cue competition, the
"discounting" of inferior candidates should occur in causal judgment.
What does the empirical evidence indicate? Causal judgments do indeed
rise in strength as a function of pairings of cause with effect
(Wasserman, Kao, Van Hamme, Katagiri, & Young, 1996), in clear
accord with the acquisition functions typically obtained in Pavlovian
appetitive and aversive conditioning. Furthermore, the mere pairing of
cause with effect may not be adequate to forge a firm causal
association. The putative cause may have to be the best among several
rival causes. Similar processes participate in associative conditioning.
One of the most celebrated cases of discounting is the so-called cue
validity effect first reported by Wagner, Logan, Haberlandt, and Price
(1968). Key to the cue validity effect is that Target Cue X is equally
often paired with the outcome in all experimental conditions. Rival Cues
A and B are differentially paired with the outcome in different
experimental conditions, in each of which only two stimulus compounds
are arranged: AX and BX. The critical result is that animals'
conditioned responses as well as humans' causal judgments display robust
discounting: Target Cue X loses associative or causal strength the more
valid Rival Cues A and B become. Indeed, the empirical functions in
both behavioral realms are strikingly similar (Wasserman, 1990).
Thus, causation and association may be strongly related empirically.
Both exhibit acquisition. Both exhibit cue competition. And, both are
explainable by associative learning theories, such as the
Rescorla-Wagner (1972) model, which mathematically embodies Hume's laws
of causal perception. Reason is not necessary to explain either.
Would Hume be pleased with this state of affairs? Definitely. He,
himself, proposed that, "... any theory, by which we explain the
operations of the understanding, or the origin and connection of the
passions in man, will acquire additional authority, if we find, that the
same theory is requisite to explain the same phenomena in all other
animals (1777/1951, p. 104)."
Reason Amid a Savage World
What then should we make of Cross's provocative opening quotation? Are
we humans hopelessly limited by the bestial cognitive mechanisms with
which we are endowed in our quest to understand and adapt to a world
which is fraught with change and complexity? What sense, if any, can be
made of rationality in humans or animals if even conceptualization and
causation are rooted in primordial behavioral processes?
Let's further explore these challenging questions.
I hope that my earlier discussions of conceptualization and causation
have persuasively documented that individually acquired adaptive
behavior is not uniquely human. These and many other findings from the
study of animal behavior and cognition further suggest that the
mechanisms of learning and adaptation are very old and widespread among
today's animal species. In point of fact, the field of comparative
cognition has for over a century studied the nature and limits of
intelligence in humans and animals; this field continues to treasure up
new discoveries which prompt us to confer greater respect to the
cognitive abilities of our animal kin (Wasserman & Zentall, 2006).
One especially interesting area of comparative cognition where new
insights are emerging concerns tool construction and use. Research with
crows (Weir, Chappell, & Kacelnik, 2002) and chimpanzees (Whiten,
Goodall, McGrew, Nishida, Reynolds, Sugiyama, Tutin, Wrangham, &
Boesch, 1999) strongly suggests that humans can no longer lay claim to
being the only tool-wielding organisms.
Arguably fundamental to tool use is the recognition that one's desired
ends are unattainable without additional assistance. A mealworm may be
wedged into a space that is too narrow to grasp; a nut may be too firm
to crack. What to do?
The obvious answer is to fashion a tool. But, which one? And, how should it be constructed and deployed?
Thus, with thwarted goals, the process of invention begins. But, is this
process purely logical, devoid of bias, and maximally functional from
the outset? Surely not.
Most human tools and contrivances--like forks, mousetraps, and
watches--rarely emerge as full-blown successes; instead, they go through
prolonged periods of development which are rife with failures and
setbacks (Petroski, 1992). The production of even the most marvelous of
human inventions seems to be subject to the same trials and errors that
led Edward Thorndike to reject rationality as an explanation for the
effects of reward and punishment on human and animal behavior. His
powerful Law of Effect was positively mindless.
Like animals, we humans do gradually learn from our past successes and
failures--both as individuals and as cultures. Such individual
acquisitions allow us to tie our shoes, to ride a bicycle, and to peel a
banana. Cultural acquisitions enable adaptive actions to be taken by
all of us who are fortunate enough to live in those cultures and to
profit from our predecessors' labors; we cannot help but be impressed by
the ways in which air conditioning, automobiles, and personal computers
have improved our lives beyond those of our grandparents.
Science itself represents another key cultural acquisition. Science has
produced innovative ways of asking and answering questions of nature
that have proven to be of unparalleled incisiveness and effectiveness;
it has also led to the very technologies that are responsible for the
manufacturing of air conditioning, automobiles, personal computers, and
countless other devices that are now common in industrialized nations.
One especially interesting illustration of the power of science is the
development and deployment of instruments and methodologies which can
disclose other animals' perception of energies to which we ourselves are
oblivious (Hughes, 1999). We are now quite familiar with the fact that
bats, whales, and dolphins can sense sounds of extreme frequencies--well
beyond the range of human hearing. But how did we discover such
ultrasonic perception?
First, we had to build instruments that both generated and detected
ultrasonic frequencies. Second, we had to develop suitable behavioral
testing methods that allowed animals to sense those ultrasounds and to
report their sensations to us.
Our remarkable success at each of these steps attests to the power and
flexibility of human cognition. But, the truth behind each of these
steps is a far cry from an optimal designer prescribing a detailed plan
of action based solely on achieving the task at hand.
Perhaps uniquely, we humans appreciate our own perceptual and cognitive
limits. Faced with those limits, we have learned--both as individuals
and as cultures--to rise above them. Our range vision is limited; so, we
have developed increasingly powerful microscopes and telescopes to
expand our range of sight. We are regrettably biased by possibly
unreliable and unrepresentative trends in data collection and
interpretation; so, we have developed sophisticated statistical tools to
guard against such biases of judgment.
Equipped with these and other tools, natural science has continued its
inexorable advance to explain and control the inorganic and organic
worlds. But, the most elusive of all of these quests is an understanding
of human nature itself. Can we ever comprehend ourselves? The
intriguing answer is "yes," but only if we continue along the same path
that science has followed in its pursuit of other natural mysteries.
References
Astley, S. L., & Wasserman, E. A. (1992). Categorical discrimination
and generalization in pigeons: All negative stimuli are not created
equal. Journal of Experimental Psychology: Animal Behavior Processes, 18, 193-207.
Bhatt, R. S., Wasserman, E. A., Reynolds, W. F., Jr., & Knauss, K.
S. (1988). Conceptual behavior in pigeons: Categorization of both
familiar and novel examples from four classes of natural and artificial
stimuli. Journal of Experimental Psychology: Animal Behavior Processes, 14, 219-234.
Hughes, H. C. (1999). Sensory exotica: A world beyond human experience. Cambridge, MA: MIT Press.
Hume, D. (1777/1951). Enquiries concerning the human understanding and concerning the principles of morals (2nd ed. edited by L. A. Selby-Bigge). London: Oxford University Press.
Hurley, S., & Nudds, M. (Eds.). (2006). Rational animals? Oxford: Oxford University Press.
Kahneman, D. A. (2003). A perspective on judgment and choice: Mapping bounded rationality. American Psychologist, 58, 697-720.
Locke, J. (1690/1975). An essay concerning human understanding. Oxford: Clarendon Press.
Petroski, H. (1992). The evolution of useful things. New York: Vintage Books.
Quine, W. V. (1969). Natural kinds. In N. Rescher (Ed.), Essays in honor of Carl G. Hempel (pp. 5-23). Dordrecht, Holland: D. Reidel.
Rescorla, R. A., & Wagner, A. R. (1972). A theory of Pavlovian
conditioning: Variations in the effectiveness of reinforcement and
nonreinforcement. In A. H. Black & W. F. Prokasy (Eds.), Classical conditioning II: Current research and theory (pp. 64-99). New York: Appleton-Century-Crofts.
Wagner, A. R., Logan, F. A., Haberlandt, K., & Price, T. (1968). Stimulus selection in animal discrimination learning. Journal of Experimental Psychology, 76, 171-180.
Wasserman, E. A. (1990). Attribution of causality to common and distinctive elements of compound stimuli. Psychological Science, 1, 298-302.
Wasserman, E. A., & Zentall, T. R. (2006). Comparative cognition: Experimental explorations of animal intelligence. New York: Oxford University Press.
Wasserman, E. A., Kao, S.-F., Van Hamme, L. J., Katagiri, M., &
Young, M. E. (1996). Causation and association. In D. R. Shanks, K. J.
Holyoak, and D. L. Medin (Eds.), Psychology of Learning and Motivation: Causal learning. San Diego: Academic Press. Pp. 207-264.
Wasserman, E. A., Kiedinger, R. E., & Bhatt, R. S. (1988).
Conceptual behavior in pigeons: Categories, subcategories, and
pseudocategories. Journal of Experimental Psychology: Animal Behavior Processes, 14, 235-246.
Wasserman, E. A., & Rovee-Collier, C. (2001). Conceptualization by
infants and pigeons. In M. E. Carroll and J. B. Overmier (Eds.), Animal research and human health: Advancing human welfare through behavioral science (pp. 263-279). Washington: American Psychological Association.
Weir, A. A. S., Chappell, J., & Kacelnik, A. (2002). Shaping of hooks in New Caledonian crows. Science, 297, 981.
Whiten, A., Goodall, J., McGrew, W. C., Nishida, T., Reynolds, V.,
Sugiyama, Y., Tutin, C. E. G., Wrangham, R. W., & Boesch, C. (1999).
Cultures in chimpanzees. Nature, 399, 682-685.
About the Author
Ed
Wasserman is the Stuit Professor of Experimental Psychology at the
University of Iowa, where he has taught and conducted research since
1972. Wasserman is a Past-President of American Psychological
Association Division 6 (Behavioral Neuroscience and Comparative
Psychology) and is the current President of Division 3 (Experimental
Psychology). His research and teaching center on the principles of
learning, memory, and cognition in humans and nonhuman animals. Ongoing
research topics include: visual object perception; associative learning
and causal perception; same-different conceptualization; and
categorization. Wasserman's research has been funded by: the National
Institute of Mental Health, the National Science Foundation, the Human
Frontier Science Program, and the Great Ape Trust of Iowa.
