Acquired equivalence of cues by presentation in a common context in rats

It is well established that humans and other animals may treat two perceptually different cues alike, if the cues have been individually paired with a common antecedent or a common consequence. Recently, Molet et al. (Psychon Bull Rev 18:618–623, 2011) reported evidence for a new form of acquired equivalence in human conditional discrimination, namely context-mediated equivalence. In the present research, using a flavor conditioning procedure, we asked whether rats would show similar context-mediated equivalence to demonstrate that this new form of acquired equivalence is a general phenomenon. Rats experienced two flavor cues A and B each presented either in the same context, X, or each in its own distinctive context, X or Y. Subsequently, the rats experienced B with sucrose in a third context, Z, and then the generalization of conditioning to A was assessed. When tested in Context Z, consumption of A was more marked when A and B had both been presented in the same context than when they had been presented in two different contexts. Thus, importantly, in the absence of the training context, cues that shared a common context at different times came to be treated as equivalent. This represents the first evidence of context-mediated equivalence in a nonhuman species.     

Imitation: definitions, evidence, and mechanisms

Imitation can be defined as the copying of behavior. To a biologist, interest in imitation is focused on its adaptive value for the survival of the organism, but to a psychologist, the mechanisms responsible for imitation are the most interesting. For psychologists, the most important cases of imitation are those that involve demonstrated behavior that the imitator cannot see when it performs the behavior (e.g., scratching one's head). Such examples of imitation are sometimes referred to as opaque imitation because they are difficult to account for without positing cognitive mechanisms, such as perspective taking, that most animals have not been acknowledged to have. The present review first identifies various forms of social influence and social learning that do not qualify as opaque imitation, including species-typical mechanisms (e.g., mimicry and contagion), motivational mechanisms (e.g., social facilitation, incentive motivation, transfer of fear), attentional mechanisms (e.g., local enhancement, stimulus enhancement), imprinting, following, observational conditioning, and learning how the environment works (affordance learning). It then presents evidence for different forms of opaque imitation in animals, and identifies characteristics of human imitation that have been proposed to distinguish it from animal imitation. Finally, it examines the role played in opaque imitation by demonstrator reinforcement and observer motivation. Although accounts of imitation have been proposed that vary in their level of analysis from neural to cognitive, at present no theory of imitation appears to be adequate to account for the varied results that have been found.     

Relationship problems and extradyadic romantic and sexual activity in a web‐sample of Norwegian men and women

The purpose of this paper is to describe the prevalence of self‐reported types of extradyadic romantic and sexual activity among adult Norwegians and to explore the role of infidelity in breaking up a permanent relationship. The results are based on 1,001 web interviews with persons ranging in age from 18 to 67 years. The majority of respondents reported having engaged in some kind of extradyadic romantic and/or sexual activity. Forty‐five percent of the women and 39% of the men claimed they had experienced a previous breakup from a marriage or cohabiting relationship. Among those aged 50 years or older, the most important reasons for breaking up a previous relationship were infidelity (38%) and lost love (38%). More men (44%) than women (33%) reported infidelity. Respondents younger than 50 years were more motivated by boredom. Among respondents below the age of 50 years, the most frequently reported reasons for considering termination of a present relationship were quarreling (37%), poor sex life (29%), and “other” reasons (25%). Accordingly, infidelity was not identified as an essential factor for considering a breakup from the present relationship.     

Symbolic Representation by Pigeons

The capacity for symbolic representation is a prerequisite for the development of human language because words, the basic units of language, are symbols that represent things. But symbolic representation may also serve a nonlinguistic role of organizing events into categories having the same meaning, and such a capacity could have considerable survival value for many species. In a number of experiments, my co-workers and I have found that pigeons that are trained to treat two different stimuli similarly also learn that those stimuli are commonly represented and, thus, that they have the same meaning. We have demonstrated evidence for such common representations in a number of ways, but perhaps the most convincing is when pigeons learn a new association involving one of the presumed commonly represented stimuli, and without further training demonstrate that they have learned a similar association involving the other stimulus. Furthermore, we have found that when pigeons are trained to treat two stimuli similarly, one of those stimuli is represented in terms of the other. These results have implications not only for the generality of cognitive processes across species, but also for the generality of symbolic representation beyond language use.     

Support for a theory of memory for event duration must distinguish between test-trial ambiguity and actual memory loss

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.     

Coding of stimuli by animals: Retrospection, prospection, episodic memory and future planning

When animals code stimuli for later retrieval they can either code them in terms of the stimulus presented (as a retrospective memory) or in terms of the response or outcome anticipated (as a prospective memory). Although retrospective memory is typically assumed (as in the form of a memory trace), evidence of prospective coding has been found when response intentions and outcomes are particularly salient. At a more abstract level is the question of whether animals are able figuratively to travel back in time to recover memories of past events (episodic memory) and forward in time to predict future events (future planning). Although what would constitute adequate evidence of episodic memory and future planning is controversial, preliminary evidence suggests that animals may be capable of both forms of subjective time travel.     

Cognitive dissonance in children: Justification of effort or contrast?

Justification of effort is a form of cognitive dissonance in which the subjective value of an outcome is directly related to the effort that went into obtaining it. However, it is likely that in social contexts (such as the requirements for joining a group) an inference can be made (perhaps incorrectly) that an outcome that requires greater effort to obtain in fact has greater value. Here we present evidence that a cognitive dissonance effect can be found in children under conditions that offer better control for the social value of the outcome. This effect is quite similar to contrast effects that recently have been studied in animals. We suggest that contrast between the effort required to obtain the outcome and the outcome itself provides a more parsimonious account of this phenomenon and perhaps other related cognitive dissonance phenomena as well. Research will be needed to identify cognitive dissonance processes that are different from contrast effects of this kind. nt]mis|This research was facilitated by a fellowship from the Fulbright Scholar Program and the Nord-Pas de Calais Regional Council, as well as by a visiting professorship at the University of Lille III for T.R.Z. Preparation of the article was facilitated by National Institute of Mental Health Grant MH 63726 to T.R.Z.