Journal of Experimental Psychology-Animal Learning and Cognition最新文献

Responding to a related pair of measurements is often expressed as a single discrimination ratio. Authors have used various discrimination ratios; yet, little information exists to guide their choice. A second use of ratios is to correct for the influence of a nuisance variable on the measurement of interest. I examine 4 discrimination ratios using simulated data sets. Three ratios, of the form a/(a + b), b/(a + b), and (a - b)/(a + b), introduced distortions to their raw data. The fourth ratio, (b - a)/b largely avoided such distortions and was the most sensitive at detecting statistical differences. Effect size statistics were also often improved with a correction ratio. Gustatory sensory preconditioning experiments involved measurement of rats' sucrose and saline consumption; these flavors served as either a target flavor or a control flavor and were counterbalanced across rats. However, sensory preconditioning was often masked by a bias for sucrose over saline. Sucrose and saline consumption scores were multiplied by the ratio of the overall consumption to the consumption of that flavor alone, which corrected the bias. The general utility of discrimination and correction ratios for data treatment is discussed. (PsycINFO Database Record

Despite the generality and theoretical relevance of cue competition phenomena such as blocking and overshadowing, recent findings suggest that these observations may be due to some degree of publication bias, and that we lack insight into the boundary conditions of these phenomena. The present commentary does not question the existence of cue competition phenomena. Rather, I review findings showing that 3 variables, namely (a) relative stimulus duration, (b) contingency, and (c) contiguity parametrically determine not only whether cue competition is observed, but also whether no cue interaction, or cue facilitation occur. I discuss theoretical interpretations and implications of these findings, which may provide illuminating insights into the generality and functional significance of the commonly cited "principles of learning." (PsycINFO Database Record

The Learned Predictiveness effect refers to the observation that learning about the relationship between a cue and an outcome is influenced by the predictive relevance of the cue for other outcomes. Similarly, the Outcome Predictability effect refers to a recent observation that the previous predictability of an outcome affects learning about this outcome in new situations, too. We hypothesize that both effects may be two manifestations of the same phenomenon and stimuli that have been involved in highly predictive relationships may be learned about faster when they are involved in new relationships regardless of their functional role in predictive learning as cues and outcomes. Four experiments manipulated both the relationships and the function of the stimuli. While we were able to replicate the standard effects, they did not survive a transfer to situations where the functional role of the stimuli changed, that is the outcome of the first phase becomes a cue in the second learning phase or the cue of the first phase becomes the outcome of the second phase. Furthermore, unlike learned predictiveness, there was little indication that the distribution of overt attention in the second phase was influenced by previous predictability. The results suggest that these 2 very similar effects are not manifestations of a more general phenomenon but rather independent from each other. (PsycINFO Database Record

Interference effects emerge when responding on the basis of task-relevant features is directly pitted against task-irrelevant cues that could lead to errors. To study potential interference effects in a food-choice memory test, 3 chimpanzees were presented with conflicting information in a magnitude judgment task. In Experiment 1, chimpanzees were presented with an ordinal series of colored containers that they sequenced on the basis of relative preference for the different foods that were consistently hidden under the containers. Chimpanzees also were presented with a relative quantity judgment task in which they saw identical containers cover different amounts of a consistent food type. Then, the ordinal and quantity tasks were combined such that the colored containers from the ordinal task were used as covers for the consistent food type from the quantity task. This created instances of congruency (e.g., a highly preferred colored container placed over the largest food quantity) and incongruency (e.g., a highly preferred colored container placed over a small food quantity) between task-relevant and task-irrelevant features. Interference effects were evident when chimpanzees responded on the basis of task-irrelevant features (i.e., container value) rather than task-relevant features (i.e., food quantity), sometimes leading to suboptimal responses in incongruent trial types. Chimpanzees also demonstrated some evidence of the cognitive control needed to inhibit responding based solely on the learned values of the containers. (PsycINFO Database Record

Risky decisions are inherently characterized by the potential to receive gains or incur losses, and these outcomes have distinct effects on subsequent decision-making. One important factor is that individuals engage in loss-chasing, in which the reception of a loss is followed by relatively increased risk-taking. Unfortunately, the mechanisms of loss-chasing are poorly understood, despite the potential importance for understanding pathological choice behavior. The goal of the present experiment was to illuminate the mechanisms governing individual differences in loss-chasing and risky-choice behaviors. Rats chose between a low-uncertainty outcome that always delivered a variable amount of reward and a high-uncertainty outcome that probabilistically delivered reward. Loss-processing and loss-chasing were assessed in the context of losses disguised as wins (LDWs), which are loss outcomes that are presented along with gain-related stimuli. LDWs have been suggested to interfere with adaptive decision-making in humans and thus potentially increase loss-making. Here, the rats presented with LDWs were riskier, in that they made more choices for the high-uncertainty outcome. A series of nonlinear models were fit to individual rats' data to elucidate the possible psychological mechanisms that best account for individual differences in high-uncertainty choices and loss-chasing behaviors. The models suggested that the rats presented with LDWs were more prone to showing a stay bias following high-uncertainty outcomes compared to rats not presented with LDWs. These results collectively suggest that LDWs acquire conditioned reinforcement properties that encourage continued risk-taking and increase loss-chasing following previous high-risk decisions. (PsycINFO Database Record

According to the biexponential refractory model (BERM) of variable-interval (VI) performance, operant behavior is organized in bouts, described by 3 dissociable components: between-bout interresponse times (IRTs), within-bout IRTs, and bout lengths. Research has shown that between-bout IRTs are sensitive to changes in rate of reinforcement and reinforcer efficacy, the length of some bouts is selectively sensitive to changes in response-reinforcer contingencies, and within-bout IRTs are relatively insensitive to both manipulations. BERM assumes that within- and between-bout IRTs are exponentially distributed, and bout lengths are described by a mixture of negative binomial and geometric distributions. To assess BERM assumptions and the interpretation of associated findings, Fischer 344/DuCrl rats were trained on a heterogeneous tandem VI fixed-ratio (FR) schedule of reinforcement intended to dissociate the components of operant behavior. Initial (VI) and terminal (FR) links were programmed on separate levers; no stimulus signaled the completion of the initial link. FR requirement, VI requirement, and deprivation level were varied. Typical performance consisted of single responses on the VI lever separated by response runs on the FR lever. It was hypothesized that (a) the interval between the end of each FR run and the first subsequent VI response (FR-VI IRTs) would constitute between-bout IRTs, and would be sensitive to changes in VI requirement and deprivation level, (b) FR runs would constitute response bouts, so the length of a fraction of them would be selectively sensitive to changes in FR requirement, and (c) intervals between consecutive FR responses (FR-FR IRTs) would constitute within-bout IRTs, and would be relatively robust to all manipulations. Findings were consistent with these expectations. The underlying distributions of FR-FR IRTs, FR-VI IRTs, and FR run lengths, however, were inconsistent with BERM assumptions. These data support the distinct components of operant performance, but challenge the simple processes assumed to underlie their generation. (PsycINFO Database Record

Prior categorization studies have shown that pigeons reliably track features that are perfect predictors of category membership (Castro & Wasserman, 2014, 2016a). One might further ask whether pigeons would also track features that are relevant, but imperfect predictors of category membership. In our present project, pigeons had to categorize multiple exemplars from 2 different artificial categories, in which the exemplars were composed of 4 different features that were associated with 1 of 2 different report responses. Each exemplar contained 1 feature that perfectly predicted category membership; 1 feature that imperfectly predicted category membership; and, 2 irrelevant features that did not predict category membership. We monitored pigeons' choice accuracy as well as the location of their pecks to each of the 4 exemplar features to determine to which attributes the birds attended. As categorization accuracy rose, pecks to the perfect predictor of each category rose as well. Pigeons also showed evidence of attending more to the imperfect predictor than to the irrelevant features, but to a lesser degree. Overall, our results provide evidence of selective attention in pigeons' categorization behavior. (PsycINFO Database Record

Many animal species can detect dependencies between adjacent visual or auditory items in a string. Compared with adjacent dependencies, detecting nonadjacent dependencies, as present in linguistic constructions, is more challenging as this requires detecting a relation between items irrespective of the number and nature of the intervening items. There is limited evidence that nonhuman animals can detect such dependencies. An animal group in which such abilities might be expected is songbirds, which have learned songs consisting of a series of vocal elements given in specific sequences. So far no songbird (or other bird species) has been tested for its ability to detect nonadjacent dependencies. We examined whether zebra finches can detect the dependencies between items at the edges of artificially arranged strings of song elements. Zebra finches were trained to discriminate 2 sets of dependent song elements that always appeared in the same order (A and B; C and D), from other element combinations (AD, AC, BD, CB, CA, DB). The element combinations were separated by intervening (I) elements. Subsequent tests revealed that the finches could generalize the learned dependencies over different numbers and types of intervening items. Our findings show that the ability for detecting nonadjacent dependencies is not limited to humans or primates, and lend support to theories that suggest that nonadjacent dependencies can be learned by a nonlinguistic associative learning process. (PsycINFO Database Record

On sequential response tasks, a long pause preceding the first response is thought to reflect participants taking time to plan a sequence of responses. By tracking the eye movements of two monkeys (Macaca fascicularis), Scarf and Colombo (2009, Eye Movements During List Execution Reveal No Planning in Monkeys [Macaca fascicularis], Journal of Experimental Psychology: Animal Behavior Processes, Vol. 35, pp. 587-592) demonstrated that, at least with respect to monkeys, the long pause preceding the first response is not necessarily the product of planning. In the present experiment, we tracked the eye movements of adult humans using the paradigm employed by Scarf and Colombo and found that, in contrast to monkeys, the pause preceding the first item is indicative of planning in humans. These findings highlight the fact that similar response time profiles, displayed by human and nonhuman animals, do not necessarily reflect similar underlying cognitive operations.

Though much work has studied how external factors, such as stimulus properties, influence generalization of associative strength, there has been limited exploration of the influence that internal dispositions may contribute to stimulus processing. Here we report 2 studies using a modified negative patterning discrimination to test the relationship between global processing and generalization. Global processing was associated with stronger negative patterning discrimination, indicative of limited generalization between distinct stimulus compounds and their constituent elements. In Experiment 2, participants pretrained to adopt global processing similarly showed strong negative patterning discrimination. These results demonstrate considerable individual difference in capacity to engage in negative patterning discrimination and suggest that the tendency toward global processing may be one factor explaining this variability. The need for models of learning to account for this variability in learning is discussed.