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Zentall, T. R. (1999). Support for a theory of memory for event duration must distinguish between test-trial ambiguity and actual memory loss. J Exp Anal Behav, 72(3), 467–472.
Abstract: Staddon and Higa's (1999) trace-strength theory of timing and memory for event duration can account for pigeons' bias to “choose short” when retention intervals are introduced and to “choose long” when, following training with a fixed retention interval, retention intervals are shortened. However, it does not account for the failure of pigeons to choose short when the intertrial interval is distinct from the retention interval. That finding suggests that stimulus generalization (or ambiguity) between the intertrial interval and the retention interval may result in an effect that has been attributed to memory loss. Such artifacts must be eliminated before a theory of memory for event duration can be adequately tested.
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Henning, J. M., & Zentall, T. R. (1981). Imitation, social facilitation, and the effects of ACTH 4-10 on rats' bar-pressing behavior. Am J Psychol, 94(1), 125–134.
Abstract: The effects of ACTH 4-10 on rats' imitation learning was examined during the acquisition and extinction of a bar-press response for water reinforcement. Rats were exposed to either a bar-pressing conspecific (OB), an experimentally naive conspecific (ON), or an empty box (OE) during bar-press acquisition. In a factorial design, each rat was then exposed to one of the same three conditions during extinction. An 80 mcg dose of ACTH 4-10 was administered to half of the rats in each group prior to observation. Performance differences during acquisition were generally small, but significant performance differences during extinction were found. Social facilitation was indicated by the finding that rats extinguished in the presence of a conspecific exhibited significantly greater resistance to extinction than rats extinguished in the presence of an empty box. An imitation effect was also found. Rats that observed a bar-pressing conspecific during both acquisition and extinction (group OB-OB) showed significantly greater resistance top extinction than did groups OB-ON, CB-OE, or OE-OE. There were no significant effects of the hormone, however, relative to saline controls.
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Flack, J. C., Girvan, M., de Waal, F. B. M., & Krakauer, D. C. (2006). Policing stabilizes construction of social niches in primates. Nature, 439(7075), 426–429.
Abstract: All organisms interact with their environment, and in doing so shape it, modifying resource availability. Termed niche construction, this process has been studied primarily at the ecological level with an emphasis on the consequences of construction across generations. We focus on the behavioural process of construction within a single generation, identifying the role a robustness mechanism--conflict management--has in promoting interactions that build social resource networks or social niches. Using 'knockout' experiments on a large, captive group of pigtailed macaques (Macaca nemestrina), we show that a policing function, performed infrequently by a small subset of individuals, significantly contributes to maintaining stable resource networks in the face of chronic perturbations that arise through conflict. When policing is absent, social niches destabilize, with group members building smaller, less diverse, and less integrated grooming, play, proximity and contact-sitting networks. Instability is quantified in terms of reduced mean degree, increased clustering, reduced reach, and increased assortativity. Policing not only controls conflict, we find it significantly influences the structure of networks that constitute essential social resources in gregarious primate societies. The structure of such networks plays a critical role in infant survivorship, emergence and spread of cooperative behaviour, social learning and cultural traditions.
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Seyfarth, R. M., Cheney, D. L., & Bergman, T. J. (2005). Primate social cognition and the origins of language. Trends. Cognit. Sci., 9(6), 264–266.
Abstract: Are the cognitive mechanisms underlying language unique, or can similar mechanisms be found in other domains? Recent field experiments demonstrate that baboons' knowledge of their companions' social relationships is based on discrete-valued traits (identity, rank, kinship) that are combined to create a representation of social relations that is hierarchically structured, open-ended, rule-governed, and independent of sensory modality. The mechanisms underlying language might have evolved from the social knowledge of our pre-linguistic primate ancestors.
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Seyfarth, R. M., & Cheney, D. L. (2001). Cognitive strategies and the representation of social relations by monkeys. Nebr Symp Motiv, 47, 145–177.
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Gentner, T. Q., Fenn, K. M., Margoliash, D., & Nusbaum, H. C. (2006). Recursive syntactic pattern learning by songbirds. Nature, 440(7088), 1204–1207.
Abstract: Humans regularly produce new utterances that are understood by other members of the same language community. Linguistic theories account for this ability through the use of syntactic rules (or generative grammars) that describe the acceptable structure of utterances. The recursive, hierarchical embedding of language units (for example, words or phrases within shorter sentences) that is part of the ability to construct new utterances minimally requires a 'context-free' grammar that is more complex than the 'finite-state' grammars thought sufficient to specify the structure of all non-human communication signals. Recent hypotheses make the central claim that the capacity for syntactic recursion forms the computational core of a uniquely human language faculty. Here we show that European starlings (Sturnus vulgaris) accurately recognize acoustic patterns defined by a recursive, self-embedding, context-free grammar. They are also able to classify new patterns defined by the grammar and reliably exclude agrammatical patterns. Thus, the capacity to classify sequences from recursive, centre-embedded grammars is not uniquely human. This finding opens a new range of complex syntactic processing mechanisms to physiological investigation.
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Ratcliffe, J. M., Fenton, M. B., & Shettleworth, S. J. (2006). Behavioral flexibility positively correlated with relative brain volume in predatory bats. Brain Behav Evol, 67(3), 165–176.
Abstract: We investigated the potential relationships between foraging strategies and relative brain and brain region volumes in predatory (animal-eating) echolocating bats. The species we considered represent the ancestral state for the order and approximately 70% of living bat species. The two dominant foraging strategies used by echolocating predatory bats are substrate-gleaning (taking prey from surfaces) and aerial hawking (taking airborne prey). We used species-specific behavioral, morphological, and ecological data to classify each of 59 predatory species as one of the following: (1) ground gleaning, (2) behaviorally flexible (i.e., known to both glean and hawk prey), (3) clutter tolerant aerial hawking, or (4) open-space aerial hawking. In analyses using both species level data and phylogenetically independent contrasts, relative brain size was larger in behaviorally flexible species. Further, relative neocortex volume was significantly reduced in bats that aerially hawk prey primarily in open spaces. Conversely, our foraging behavior index did not account for variability in hippocampus and inferior colliculus volume and we discuss these results in the context of past research.
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Skov-Rackette, S. I., & Shettleworth, S. J. (2005). What do rats learn about the geometry of object arrays? Tests with exploratory behavior. J Exp Psychol Anim Behav Process, 31(2), 142–154.
Abstract: Six experiments using habituation of exploratory behavior tested whether disoriented rats foraging in a large arena encode the shapes of arrays of objects. Rats did not respond to changes in position of a single object, but they responded to a change in object color and to a change in position of 1 object in a square array, as in previous research (e.g., C. Thinus-Blanc et al., 1987). Rats also responded to an expansion of a square array, suggesting that they encoded sets of interobject distances rather than overall shape. In Experiments 4-6, rats did not respond to changes in sense of a triangular array that maintained interobject distances and angles. Shapes of object arrays are encoded differently from shapes of enclosures.
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Shettleworth, S. J., & Sutton, J. E. (2005). Multiple systems for spatial learning: dead reckoning and beacon homing in rats. J Exp Psychol Anim Behav Process, 31(2), 125–141.
Abstract: Rats homed with food in a large lighted arena. Without visual cues, they used dead reckoning. When a beacon indicated the home, rats could also use the beacon. Homing did not differ in 2 groups of rats, 1 provided with the beacon and 1 without it; tests without the beacon gave no evidence that beacon learning overshadowed dead reckoning (Experiment 1). When the beacon was at the home for 1 group and in random locations for another, there was again no evidence of cue competition (Experiment 2). Dead reckoning experience did not block acquisition of beacon homing (Experiment 3). Beacon learning and dead reckoning do not compete for predictive value but acquire information in parallel and are used hierarchically.
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Gibson, B. M., & Shettleworth, S. J. (2003). Competition among spatial cues in a naturalistic food-carrying task. Learn Behav, 31(2), 143–159.
Abstract: Rats collected nuts from a container in a large arena in four experiments testing how learning about a beacon or cue at a goal interacts with learning about other spatial cues (place learning). Place learning was quick, with little evidence of competition from the beacon (Experiments 1 and 2). Rats trained to approach a beacon regardless of its location were subsequently impaired when the well-learned beacon was removed and other spatial cues identified the location of the goal (Experiment 3). The competition between beacon and place cues reflected learned irrelevance for place cues (Experiment 4). The findings differ from those of some studies of associative interactions between cue and place learning in other paradigms.
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