The simultaneous chain: a new approach to serial learning

Abstract

Recent advances have allowed the application of behaviorism's rigor to the control of complex cognitive tasks in animals. This article examines recent research on serially organized behavior in animals. 'Chaining theory', the traditional approach to the study of such behavior, reduces intelligent action to sequences of discrete stimulus-response units in which each overt response is evoked by a particular stimulus. However, such theories are too weak to explain many forms of serially organized cognition, both in humans and animals. By training non-human primates to produce arbitrary sequences that cannot be learned as chains of particular motor responses, the simultaneous chaining paradigm has overcome limitations of chaining theory in experiments on serial expertise, the use of numerical rules, knowledge of ordinal position, and distance and magnitude effects. IntroductionThe psychology of the conditioned response is arguably behaviorism's major achievement. Sophisticated theories of conditioning [1] have been applied to a wide range of behavior and those principles have led to the discovery of neural mechanisms of conditioned behavior at cortical [2], sub-cortical [3] and cellular [4] levels of the brain. Unfortunately for behaviorism, its major achievement exposed its major limitation. Intelligent behavior is greater than the sum of discrete conditioned responses. Although it was once hoped that chaining theory could explain how individually conditioned responses could be linked together to form complex sequences [5], there is ample theoretical and empirical evidence that many forms of serially organized behavior are beyond its grasp (see Box 1). What is needed is an animal model of serially organized behavior that is based on learning ordinal relationships between stimuli rather than on the conditioning of new responses.One of the main attractions of behaviorism is its rigorous, non-verbal methodology. There is, however, nothing inherent in that methodology that restricts its application to research on conditioning. Recent advances in technology have facilitated the application of behaviorism's rigor to the control of complex cognitive tasks in animals [6]; for example, concept formation [7], timing [8],

Budgerigars and zebra finches differ in how they generalize in an artificial grammar learning experiment

“…For instance, when pigeons are trained to respond to sequences with an A-B-C-D structure (the letters depicting different image categories), they respond more quickly when they see new strings in which the category items are in the original ordinal position than when they see strings in which the category items are switched (e.g., A-C-B-D) (45,46). A similar mapping of items to positions in both string-discrimination and food-localization paradigms has been noted in several primate species (20,47,48). While the positional learning as observed in the zebra finches is thus not uncommon, the detailed memory for item positions that they demonstrate in the current experiment is impressive, as they kept track of item positions over a set of ten training strings.…”

Direct and relational representation during transitive list linking in pinyon jays (Gymnorhinus cyanocephalus).

“…Even in the first three sessions of the first test block (filled circles, Figure 5), the birds responded fastest to pairs that were at the top of List X (A > B and B > C) and slowest to the last two pairs of List Y (3 > 4 and 4 > 5). Terrace (2005) has suggested that this pattern of increasing latency with distance from the top of the hierarchy is diagnostic of a relational representation.…”

Evidence of Action Sequence Chunking in Goal-Directed Instrumental Conditioning and Its Dependence on the Dorsomedial Prefrontal Cortex

“…However, such tasks reveal little about the strategy subjects use to perform an action sequence. For instance, because subjects are provided with discriminative cues that signal the identity of the response to be performed next, they may come to solve the task by learning a set of simple stimulus-response associations rather than by encoding the entire sequence of actions (Terrace, 2005). Alternatively, action sequence learning may be aided by the capacity to construct, or chunk, hierarchical action representations out of more elementary units of behavior (Lashley, 1951;Miller et al, 1960;Rosenbaum et al, 1983).…”

“…For example, obtaining a goal often involves performing a sequence of two or more discrete actions. Although rats and other animals can be trained to perform action sequences of this kind, there is considerable debate about what is learned in such tasks (Terrace, 2005). One possibility is that the entire sequence becomes represented (perhaps through an action chunking process) as an integrated unit of behavior capable of entering into associations with discriminative cues and/or rewards (Lashley, 1951;Miller et al, 1960;Rosenbaum et al, 1983).…”