International Journal of Comparative Psychology

Researchers within the field of learning have traditionally divided their empirical world according to methodology, with phenomena classified as single stimulus learning, Pavlovian conditioning, or instrumental learning. This trichotomy, a vestige of our behaviorist past, continues to influence the field, both in the classroom and in the laboratory. Relying on data collected using a simple model system (learning within the mammalian spinal cord), evidence is presented that organisms can learn about an environmental relationship in multiple ways, an observation that argues against a simple isomorphism between methodology and mechanism. It is suggested that a new classification system is needed that focuses on mechanism rather than methodology, subdividing our empirical world along lines that make sense given commonalties in the neural-functional mechanisms involved.

Grau and Joynes (2005) assess the current state of the field of animal learning and behavior, with particular emphasis on pedagogical and curricular issues. They suggest that the conventional framework which organizes lecture material around methodology is flawed and that an organization around mechanism should be used instead. They also advocate a shift from a purely behavioral approach to research on learning and behavior to a neural-functionalist approach more akin to contemporary behavioral neuroscience. While I support many of the suggestions for improving instruction, I disagree with their proposed shift away from purely behavioral investigations of animal behavior. Behavioral research continues to be a thriving and productive source of empirical and theoretical discoveries. The diverse array of specialized methodologies that have been developed to pursue this work are still paying dividends by illuminating the nature of behavioral mechanisms. Banishing purely behavioral approaches to learning and behavior, such as those used to study associative learning, animal cognition, and comparative psychology, would severely hamper our knowledge of behavioral mechanism.

According to Grau and Joynes (2005), (1) the current classification of types of learning is based on methodology and assumes a correspondence between types of learning and distinct neural-functional mechanisms; (2) this assumption is wrong because experiments show that different mechanisms may underlie the same type of learning; consequently, (3) we should change the teaching of the psychology of learning. I argue that because Grau and Joynes misunderstood the nature of the classification of learning phenomena and cloaked their research findings with a garb of conceptual errors and infelicities, their recommendations concerning the teaching of learning should be rejected.

According to Grau and Joynes (2005), (1) the current classification of types of learning is based on methodology and assumes a correspondence between types of learning and distinct neural-functional mechanisms; (2) this assumption is wrong because experiments show that different mechanisms may underlie the same type of learning; consequently, (3) we should change the teaching of the psychology of learning. I argue that because Grau and Joynes misunderstood the nature of the classification of learning phenomena and cloaked their research findings with a garb of conceptual errors and infelicities, their recommendations concerning the teaching of learning should be rejected.

History has revealed time and time again that science is moved forward by revolutions that pit one point of view, theory, or methodology, against an opposing view. During calmer times, however, we as researchers are left to our own devices and settle into our work with little thought to the world around us. The field of learning and memory has been privy to many such revolutions in the past but has yet to form a cohesive, modern message. Grau and Joynes suggest that our strong ties to the past are to blame for a lack of progression in the field. We agree and add that the focus of the field on two extreme ends of a continuum has also held us back; suggesting that research that goes on in the middle of the continuum may be the key to leading the field out of its rut.

Procedures are not the same as processes. But purposive modules are probably no more than a waystation to understanding learning processes and may not be as simply represented in brain neurophysiology as many seem to assume. And finally: it is impossible (and therefore unwise) to specify in advance what the ultimate theory of learning must explain.

Studies of learning in simple systems (invertebrates and spinal cord) have revealed that organisms can encode stimulus-stimulus (Pavlovian) and response-outcome (instrumental) relations in multiple ways. It is suggested that nonassociative mechanisms contribute to learning and that there is value in adopting an approach that details the neural-functional mechanisms involved. Reactions to this approach are discussed. The link between the methods of Pavlov and associative (“true”) learning is deeply ingrained and, some believe, should be maintained. We suggest that there is value in dissociating the concepts and seek to clarify the implications of a neurofunctionalist approach to learning. It is argued that a neural-functionalist approach provides a better framework for integrating behavioral and neurobiological observations.

Palaeoanthropology, the study of the fossil evidence for human evolution, remains a highly contested field. New discoveries are continuously being used to promote alternative models as well as to propose new candidates for our ultimate ancestor. The fossil evidence has increased over the years, and has been supplemented (and often challenged) by molecular data drawn from living people and the great apes. As recently as the 1980s, palaeoanthropologists proposed that human roots stretched back into the Middle Miocene, between 17 and 8 million years ago. Then the earliest true hominids or human ancestors became the South African australopithecines, who are less than 5 million years old. Now there appears to be a tremendous variety of early humans at all stages of their evolution. Along with this new research on the basal hominids has been a renewed interest about what it means to be Homo sapiens . Molecular and fossil data shows that Africa was also our homeland, and that all people today are descended from a small founder population in existence there between 50,000 and 200,000 years ago.

Posttraining administration of cholinergic drugs modulates the consolidation of memory processes in several learning tasks. We studied the effect of the administration of atropine (cholinergic antagonist, Experiment 1) and physostigmine (acetylcholinesterase inhibitor, Experiment 2) immediately after the first session of reward downshift, and immediately after the last preshift session (Experiment 3) on a consummatory successive negative contrast procedure. Animals were given access to a high-value reward (32% sucrose solution), and surprisingly shifted to a low-value reward (4% sucrose solution) in a second phase. The results indicate that atropine and physostigmine have no effects on contrast. The role of cholinergic neurotransmission in the memory of surprising reward changes is discussed.