Expectations about numerical events in four lemur species (Eulemur fulvus, Eulemur mongoz, Lemur catta and Varecia rubra)

Although much is known about how some primates—in particular, monkeys and apes—represent and enumerate different numbers of objects, very little is known about the numerical abilities of prosimian primates. Here, we explore how four lemur species (Eulemur fulvus, E. mongoz, Lemur catta, and Varecia rubra) represent small numbers of objects. Specifically, we presented lemurs with three expectancy violation looking time experiments aimed at exploring their expectations about a simple 1+1 addition event. In these experiments, we presented subjects with displays in which two lemons were sequentially added behind an occluder and then measured subjects duration of looking to expected and unexpected outcomes. In experiment 1, subjects looked reliably longer at an unexpected outcome of only one object than at an expected outcome of two objects. Similarly, subjects in experiment 2 looked reliably longer at an unexpected outcome of three objects than at an expected outcome of two objects. In experiment 3, subjects looked reliably longer at an unexpected outcome of one object twice the size of the original than at an expected outcome of two objects of the original size. These results suggest that some prosimian primates understand the outcome of simple arithmetic operations. These results are discussed in light of similar findings in human infants and other adult primates.This revised version was published online in March 2005 with corrections to Fig. 6.     

Representing tools: how two non-human primate species distinguish between the functionally relevant and irrelevant features of a tool

Few studies have examined whether non-human tool-users understand the properties that are relevant for a tool's function. We tested cotton-top tamarins (Saguinus oedipus) and rhesus macaques (Macaca mulatta) on an expectancy violation procedure designed to assess whether these species make distinctions between the functionally relevant and irrelevant features of a tool. Subjects watched an experimenter use a tool to push a grape down a ramp, and then were presented with different displays in which the features of the original tool (shape, color, orientation) were selectively varied. Results indicated that both species looked longer when a newly shaped stick acted on the grape than when a newly colored stick performed the same action, suggesting that both species perceive shape as a more salient transformation than color. In contrast, tamarins, but not rhesus, attended to changes in the tool's orientation. We propose that some non-human primates begin with a predisposition to attend to a tool's shape and, with sufficient experience, develop a more sophisticated understanding of the features that are functionally relevant to tools.     

Bayesian parameter estimation in the Expectancy Valence model of the Iowa gambling task

The purpose of the popular Iowa gambling task is to study decision making deficits in clinical populations by mimicking real-life decision making in an experimental context. Busemeyer and Stout [Busemeyer, J. R., & Stout, J. C. (2002). A contribution of cognitive decision models to clinical assessment: Decomposing performance on the Bechara gambling task. Psychological Assessment, 14, 253-262] proposed an “Expectancy Valence” reinforcement learning model that estimates three latent components which are assumed to jointly determine choice behavior in the Iowa gambling task: weighing of wins versus losses, memory for past payoffs, and response consistency. In this article we explore the statistical properties of the Expectancy Valence model. We first demonstrate the difficulty of applying the model on the level of a single participant, we then propose and implement a Bayesian hierarchical estimation procedure to coherently combine information from different participants, and we finally apply the Bayesian estimation procedure to data from an experiment designed to provide a test of specific influence.     

Anxiety and expectancy violations: Neural response to false feedback is exaggerated in worriers

This study investigated how individual differences in anxiety modulate the neural response to errors and performance feedback. The design included false feedback on some trials in order to test the hypothesis that anxious people show stronger neural reactions to feedback that is worse than expected. Participants completed a trial-and-error learning task that required learning the correct key to press in response to face images. EEG was recorded during the task, and the response-locked error-related negativity (ERN) and feedback-locked ERN were computed to measure neural responses to error commission and feedback. As expected, errors produced a response-locked ERN and false feedback produced a feedback-locked ERN in the group as a whole. High levels of trait worry predicted a disproportionately larger ERN following false feedback, but did not predict the magnitude of the response-locked ERN following errors. These results imply that worry-prone people react more strongly to violations of expectations, rather than to errors themselves.     

Body size and body esteem in women: The mediating role of possible self expectancy

We predicted that an expectancy of acquiring a feared fat self and an expectancy of acquiring a hoped-for thin self both mediate the impact of body size on women's body esteem. We also predicted that the mediating pathway through the feared fat self would be stronger than that through the hoped-for thin self. A community sample of 251 women reported their age, height, weight, and completed measures of body esteem and expectancy perceptions of acquiring the feared fat and hoped-for thin selves. Bayesian Structural Equation Modeling (SEM) demonstrated that expectancies about the feared fat self and about the hoped-for thin self mediated the relationship between body size and body esteem. Bayesian SEM also revealed that the pathway through the feared fat self was stronger than that through the hoped-for thin self. Implications for future research and the development of eating pathology are discussed.     

Discrimination between hopes and expectancies for nonvolitional outcomes: psychological phenomenon or artifact?

Despite the large literature concerning the impact of hope and expectancy on various outcomes (e.g., nonvolitional), less is known about the constructs of hope and expectancy themselves. In a recent study, Montgomery et al. (2003) demonstrated that hopes and expectancies are separate but related constructs; however, because both hopes and expectancies were measured within the same context, it is possible that these findings were simply a methodological artifact. Furthermore, it is unknown whether these data would generalize to other populations. Taking into account the importance of this distinction for both the expectancy and hope literatures, the present study sought to: (1) Determine if the distinction between hope and expectancy is a general and reliable phenomenon by using a culturally different sample (i.e., Romanian sample); and (2) Examine the robustness of this distinction by controlling for the context effect. One hundred-twenty five volunteers completed items in regard to 10 nonvolitional outcome scenarios in one of five measurement contexts. The results revealed that hope and expectancy were distinct constructs (p<0.0001), and that this distinction is both general and robust across contexts. Implications for theory and research are discussed.     

Allocation of attention in familiar and unfamiliar traffic scenarios

Increased travel worldwide has led to an escalation of road traffic accidents, particularly among tourists driving in unfamiliar, opposite traffic flow driving scenarios. Ability to allocate attention to driving-relevant information and regions is predicted to be the main cause of tourist accidents, with a lack of attention directed to areas of space that are inhibited in familiar traffic conventions but relevant in overseas driving. This study investigated the influence of habit and expectancy on driver behaviour and allocation of attention in familiar (left-hand traffic; LHT) and unfamiliar (right-hand traffic; RHT) contexts. Twenty-eight drivers from the UK were presented with video clips of driving taken in the UK and in Poland and asked to judge whether it was safe to enter a roundabout in each clip. Half were given information about differences in LHT and RHT situations prior to the task. Judgement performance was not influenced by this information, however accuracy was higher for LHT and the RHT task was rated more difficult, supporting the notion that driving in unfamiliar surroundings is more effortful. In LHT both groups made more fixations to the right side of each roundabout, however in RHT, whilst the control group allocated attention in the same way, the intervention group made significantly more fixations to the left. Pre-drive preparatory information can therefore increase attention to the most relevant areas of space in unfamiliar driving contexts. This has implications for drive tourism and it is suggested that such information is made more explicit to drivers.     

Attention and expectation in human predictive learning: The role of uncertainty

Three localized, visual pattern stimuli were trained as predictive signals of auditory outcomes. One signal partially predicted an aversive noise in Experiment 1 and a neutral tone in Experiment 2, whereas the other signals consistently predicted either the occurrence or absence of the noise. The expectation of the noise was measured during each signal presentation, and only participants for whom this expectation demonstrated contingency knowledge showed differential attention to the signals. Importantly, when attention was measured by visual fixations, the contingency-aware group attended more to the partially predictive signal than to the consistent predictors in both experiments. This profile of visual attention supports the Pearce and Hall (1980) Pearce, J. M. and Hall, G. 1980. A model for Pavlovian learning: Variations in the effectiveness of conditioned but not unconditioned stimuli. Psychological Review, 87: 532–552. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] theory of the role of attention in associative learning.     

Reward expectancy promotes generalized increases in attentional bias for rewarding stimuli

Expectations of drug availability increase the magnitude of attentional biases for drug-related cues. However, it is unknown whether these effects are outcome specific, or whether expectation of a specific reinforcer produces a general enhancement of attentional bias for other types of rewarding cues. In the present study, 31 social drinkers completed an eye-tracking task in which attentional bias for alcohol- and chocolate-related cues was assessed while the expectation of receiving alcohol and chocolate was manipulated on a trial-by-trial basis. Participants showed attentional bias for alcohol and chocolate cues (relative to neutral cues) overall. Importantly, these attentional biases for reward cues were magnified when participants expected to receive alcohol and chocolate, but effects were not outcome specific: The expectation of receiving either alcohol or chocolate increased attentional bias for both alcohol and chocolate cues. Results suggest that anticipation of reward produces a general rather than an outcome-specific enhancement of attentional bias for reward-related stimuli.     

Development of the Anxiety Change Expectancy Scale (ACES) and validation in college, community, and clinical samples

This study investigated the psychometric properties of a newly developed 20-item instrument that assesses one's anticipation of being able to change anxiety: the Anxiety Change Expectancy Scale (ACES). Study 1 evaluated the ACES in undergraduate university students, self-identified as experiencing difficulties with anxiety. Study 2 examined the ACES in a community sample of persons with anxiety difficulties. Study 3 tested the utility of the ACES in predicting treatment change in a group of individuals with generalized anxiety disorder participating in group cognitive behavioral therapy for anxiety. Across these samples, the ACES demonstrated excellent internal reliability (coefficient alphas=.89–.92) as well as good convergent, divergent, and factorial validity. The ACES was also significantly predictive of treatment-related changes in somatic anxiety symptoms and worry. The results of these studies provide strong support for the ACES as a reliable and valid measure of expectancies for changing anxiety.