Analog number representations in mongoose lemurs (Eulemur mongoz): evidence from a search task

A wealth of data demonstrating that monkeys and apes represent number have been interpreted as suggesting that sensitivity to number emerged early in primate evolution, if not before. Here we examine the numerical capacities of the mongoose lemur (Eulemur mongoz), a member of the prosimian suborder of primates that split from the common ancestor of monkeys, apes and humans approximately 47–54 million years ago. Subjects observed as an experimenter sequentially placed grapes into an opaque bucket. On half of the trials the experimenter placed a subset of the grapes into a false bottom such that they were inaccessible to the lemur. The critical question was whether lemurs would spend more time searching the bucket when food should have remained in the bucket, compared to when they had retrieved all of the food. We found that the amount of time lemurs spent searching was indicative of whether grapes should have remained in the bucket, and furthermore that lemur search time reliably differentiated numerosities that differed by a 1:2 ratio, but not those that differed by a 2:3 or 3:4 ratio. Finally, two control conditions determined that lemurs represented the number of food items, and neither the odor of the grapes, nor the amount of grape (e.g., area) in the bucket. These results suggest that mongoose lemurs have numerical representations that are modulated by Webers Law.     

Use of situational judgment tests to predict job performance: a clarification of the literature

Although situational judgment tests have a long history in the psychological assessment literature and continue to be frequently used in employment contexts, there has been virtually no summarization of this literature. The purpose of this article is to review the history of such tests and present the results of a meta-analysis on criterion-related and construct validity. On the basis of 102 coefficients and 10,640 people, situational judgment tests showed useful levels of validity (rho = .34) that were generalizable. A review of 79 correlations between situational judgment tests and general cognitive ability involving 16,984 people indicated that situational judgment tests typically evidence relationships with cognitive ability (rho = .46). On the basis of the literature review and meta-analytic findings, implications for the continued use of situational judgment tests are discussed, particularly in terms of recent investigations into tacit knowledge.     

The negative cascade of incongruent generative study-test processing in memory and metacomprehension

Previous research suggests that when participants engage in generative study activities, the processing of text is enhanced and improvements in memory and metacomprehension result. However, few studies have investigated the influence of processes required by the testing situation or the interaction between encoding and retrieval processes on metacomprehension accuracy. The present experiments examine whether the congruency of processes generated during study and required at retrieval affect memory, metacomprehension, and control processes. Study orientation and test type were congruent (i.e., letter-reinsertion: detailed test), incongruent (i.e., letter-reinsertion: conceptual test), or neutral (i.e., read: conceptual test). After generative study, but before testing, participants made metacomprehension predictions for previously studied texts. Controlled strategy selection was measured in Experiment 2. When processes at study and test were congruent, cued recall performance and metacomprehension predictions were more accurate than when study and test were incongruent. For incongruent conditions, metacomprehension predictions were no better than chance; thus, controlled strategy selection was based on inaccurate metacomprehension, thereby further penalizing memory performance relative to congruent conditions. These findings extend a transfer-appropriate processing framework to metacomprehension.     

Nonverbal representation of time and number in adults

A wealth of human and animal research supports common neural processing of numerical and temporal information. Here we test whether adult humans spontaneously encode number and time in a paradigm similar to those previously used to test the mode-control model in animals. Subjects were trained to classify visual stimuli that varied in both number and duration as few/short or many/long. Subsequently subjects were tested with novel stimuli that varied time and held number constant (eight flashes in 0.8-3.2s) or varied number and held time constant (4-16 flashes in 1.6s). Adult humans classified novel stimuli as many/long as monotonic functions of both number and duration, consistent with simultaneous, nonverbal, analog encoding. Numerical sensitivity, however, was finer than temporal sensitivity, suggesting differential salience of time and number. These results support the notion that adults simultaneously represent the number and duration of stimuli but suggest a possible asymmetry in their representations.     

Topiramate attenuates a transient learning deficit after lesions inducing intracerebral hemorrhage

28 male Long-Evans rats prepared with lesions of the middle cerebral artery displayed deficits in spatial navigational learning in a simple version of the Morris Water Maze task not seen in animals prepared with the same injury but administered 4 treatments with topiramate after surgery.     

Target preexposure eliminates the effect of distraction on event-based prospective memory

Prospective memory is critical to everyday functioning and can be vulnerable to distraction. We conducted an experiment to explore whether we could buffer prospective memory against distraction. For half the participants, we preexposed stimuli that were later designated as prospective memory targets. Then, all participants performed an ongoing task (in which the prospective memory task was embedded) under standard and high attentional demand (i.e., under full and divided attention). Target preexposure improved prospective memory and eliminated the significant divided attention effect. Thus, target preexposure seems to buffer prospective memory against the disruptive effect of dividing attention. Moreover, target preexposure seemed to help participants to respond with the correct intended action. This result implies that preexposure to the target stimuli facilitated the encoding of an association between the target stimuli and the intended action, perhaps promoting relatively more reflexive retrieval and thereby buffering prospective memory against distraction.     

Bizarre imagery, interference, and distinctiveness

Previous studies have shown that bizarre and common images produce equivalent levels of recall in unmixed-list designs. Using unmixed lists, we tested the view that bizarre images would be less susceptible than common images to common sources of interference. In all experiments, subjects imaged a list of either bizarre or common sentences and then performed some kind of interfering task before recalling the initial list of sentences. Experiment 1 showed that bizarre images were better accessed than common images after imaging an intervening list of common sentences. Also, components of common images tended to be better recalled than those of bizarre images after imaging an intervening list of bizarre sentences. Experiments 2a and 2b showed that interfering tasks consisting of studying lists of common concrete nouns did not differentially affect memory for bizarre and common images. In Experiment 3, labeling and imaging an interfering list of common pictures produced higher recall of bizarre images. Generally, bizarre images appeared to be less susceptible than common images to interference from certain types of common encodings. Importantly, the superior recall of bizarre images was always due to greater image (sentence) access, whereas higher recall of common images was associated with greater recovery of the image (sentence) constituents. Explanation of the precise pattern of results requires consideration of the distinctive properties of bizarre images.     

A characterization of individual differences in prospective memory monitoring using the Complex Ongoing Serial Task

Prospective memory--remembering to retrieve and execute future goals--is essential to daily life. Prospective remembering is often achieved through effortful monitoring; however, potential individual differences in monitoring patterns have not been characterized. We propose 3 candidate models to characterize the individual differences present in prospective memory monitoring: attentional focus, secondary memory retrieval, and information thresholding. Two experiments using a novel paradigm, the Complex Ongoing Serial Task (COST), investigated the resource allocation patterns underlying individual differences in monitoring. Individuals exhibited differential resource allocation patterns, and the differences remained relatively stable across experimental sessions. Resource allocation patterns associated with information thresholding (high prospective memory, preserved ongoing task performance) and attentional focus (high prospective memory, inefficient ongoing task performance) were superior to secondary memory retrieval (low prospective memory, very inefficient ongoing task performance). Importantly, personality (openness, prevention focus) and cognitive (primary, working, and secondary memory) individual differences influenced monitoring patterns. This research represents the first explicit attempt to elucidate individual differences in prospective memory monitoring patterns.