Emergence of an egocentric cue guiding and allocentric inferring strategy that mirrors hippocampal brain-derived neurotrophic factor (BDNF) expression in the Morris water maze

From insects to humans, successful navigation relies on retained representations of spatial relations. These representations are thought to depend on the hippocampal formation, particularly those that are independent of the navigator (allocentric representations). The Morris water maze is a simple and popular task often used to assess spatial navigation. But how animals navigate toward and retain information regarding the location of the goal in this task remains unclear. We provide a comprehensive account of how the water maze is accomplished behaviourally. Our findings suggest that animals solve the task using distal cues via an initial view-matching strategy that is supported by egocentric guidance. Through increased training, however, an emergence of an egocentric-guiding strategy combined with the animal’s greater ability to infer the hidden platform’s location (via allocentric extrapolation) emerges. We also demonstrate that behavioural changes, towards a more allocentric strategy, are reflected in increases in hippocampal brain-derived neurotrophic factor.     

A Meta-model of Access Control in a Fibred Security Language

The issue of representing access control requirements continues to demand significant attention. The focus of researchers has traditionally been on developing particular access control models and policy specification languages for particular applications. However, this approach has resulted in an unnecessary surfeit of models and languages. In contrast, we describe a general access control model and a logic-based specification language from which both existing and novel access control models may be derived as particular cases and from which several approaches can be developed for domain-specific applications. We will argue that our general framework has a number of specific attractions and an implication of our work is to encourage a methodological shift from a study of the particulars of access control to its generalities.     

The time course of object encoding

Four experiments examined the effects of encoding time on object identification priming and recognition memory. After viewing objects in a priming phase, participants identified objects in a rapid stream of non-object distracters; display times were gradually increased until the objects could be identified (Experiments 1-3). Participants also made old/new recognition judgments about previously viewed objects (Experiment 4). Reliable priming for object identification occurred with 150 ms of encoding and reached a maximum after about 300 ms of encoding time. In contrast, reliable recognition judgments occurred with 75 ms of encoding and continued to improve for encoding times of up to 1200 ms. These results suggest that recognition memory may be based on multiple levels of object representation, from rapidly activated representations of low-level features to semantic knowledge associated with the object. In contrast, priming in this object identification task may be tied specifically to the activation of representations of object shape.     

An Investigation of Stereotype Threat in Employment Tests1

This investigation extends stereotype threat research by examining its effect on sex and ethnicity in employment testing. Study 1 used archival data from a company‐specific cognitive ability test, demonstrating score increases (greater for some minorities) when applicants completed demographic items after a cognitive skills test, rather than before the test. The first experiment (Study 2) used college students taking the same company‐specific test with inconclusive results. Possible reasons dictated the design of a second experiment with a college population (Study 3). This study used the Wonderlic Personnel Test (WPT) and investigated priming through positioning of demographic items, as well as high/low threat. Positioning of the demographic items after the WPT was associated with an increase in test scores.     

Match Madness: Probability Matching in Prediction of the NCAA Basketball Tournament1

Every year, billions of dollars are spent gambling on the outcomes of the NCAA men's basketball tournament. This study examines how individuals make predictions for tournament pools, one of the most popular forms of betting, in which individuals must correctly predict as many games in the tournament as possible. We demonstrate that individuals predict more upsets (i.e., wins by a higher seeded team) than would be considered rational by a normative choice model, and that individuals are no better than chance at doing so. These predictions fit a pattern of probability matching, in which individuals predict upsets at a rate equal to past frequency. This pattern emerges because individuals believe the outcomes of the games are nonrandom and, therefore, predictable.     

Growth and pruning of mushroom body Kenyon cell dendrites during worker behavioral development in the paper wasp, Polybia aequatorialis (Hymenoptera: Vespidae)

Adult workers of some social insect species show dramatic behavioral changes as they pass through a sequence of task specializations. In the paper wasp, Polybia aequatorialis, female workers begin adult life within the nest tending brood, progress to maintaining and defending the nest exterior, and ultimately leave the nest to forage. The mushroom body (MB) calyx neuropil increases in volume as workers progress from in-nest to foraging tasks. In other social Hymenoptera (bees and ants), MB Kenyon cell dendrites, axons and synapses change with the transition to foraging, but these neuronal effects had not been studied in wasps. Furthermore, the on-nest worker of Polybia wasps, an intermediate task specialization not identified in bees or ants, provides the opportunity to study pre-foraging worker class transitions. We asked whether Kenyon cell dendritic arborization varies with the task specialization of Polybia workers observed in the field near Monteverde, Costa Rica. Golgi-impregnated arbors in the lip and collar calyces, which receive a predominance of olfactory and visual input, respectively, were quantified using Sholl’s concentric circles and a novel application of virtual spherical probes. Arbors of the lip varied in a manner reminiscent of honeybees, with foragers having the largest and in-nest workers having the smallest arbors. In contrast, arbors of the collar were largest in foragers but smallest in on-nest workers. Thus, progression through task specializations in P. aequatorialis involves subregion specific dendritic growth and regression in the MB neuropil. These results may reflect the sensitivity of Kenyon cell dendritic structure to specialization dependent social and sensory experience.     

Exploring the route choice decision-making process: A comparison of planned and observed routes obtained using person-based GPS

Trip decisions are complex and involve choosing the activity destination, mode and subsequently the route for travel. This paper presents detailed information on the planned and observed route choices for the home-to-work commute. Specifically, the study examines how people formulate their route plans and describe their attitudes and preferences for their selected routes. A geographic information system (GIS) records the planned route information with the route planning sequence. Observing route choice is a difficult procedure; however, through the use of the global positioning system (GPS), one can accurately record route choice. An automated activity–trip detection algorithm processes GPS data and displays results within an internet-based prompted recall diary. The diary is used to verify trip start and end times. This combination of GPS, GIS and diary responses provides great insight into the route choice decision-making process. Thirty-one individuals from Ontario, Canada participated in answering survey questions and the collection of person-based GPS data. Results indicate a preference to minimize travel time as stated by participants in deciding what route to travel. Participants also affirmed a desire to minimize the number of stop lights/signs, as well as, avoid congestion and maximize route directness. A comparison between planned and observed routes, reveals about one-fifth of participants deviated from their planned route. This study demonstrates the need for qualitative and quantitative survey methods for exploring planned and observed route choice.     

Mnemonic Context Effect in Two Cultures: Attention to Memory Representations?

In two experiments we demonstrate a substantial cross-cultural difference in a mnemonic context effect, whereby a magnitude estimate of a simple stimulus such as a line or circle is biased toward the center of the distribution of previously seen instances of the same class. In support of the hypothesis that Asians are more likely than Americans to disperse their attention to both the target stimulus and its mnemonic context, this effect was consistently larger for Japanese than for Americans. Moreover, the cultural difference was attenuated by an experimentally induced belief in class homogeneity that augmented the context effect itself in both cultures. More important, these belief effects happened in the absence of any objective change in stimulus distribution. Implications for sociocultural shaping of cognition are discussed.     

Competitive state anxiety and self-confidence: intensity and direction as relative predictors of performance on a golf putting task

This study considered relationships between the intensity and directional aspects of competitive state anxiety as measured by the modified Competitive Sport Anxiety Inventory-2(D) (Jones & Swain, 1992) in a sample of 12 experienced male golfers. Anxiety and performance scores from identical putting tasks performed under three different anxiety-manipulated competitive conditions were used to assess both the predictions of Multidimensional Anxiety Theory (MAT; Martens et al., 1990) and the relative value of intensity and direction in explaining performance variance. A within-subjects regression analysis of the intra-individual data showed partial support for the three MAT hypotheses. Cognitive anxiety intensity demonstrated a negative linear relationship with performance, somatic anxiety intensity showed a curvilinear relationship with performance, and self-confidence intensity revealed a positive linear relation. Cognitive directional anxiety illustrated a positive linear relationship with putting performance. Multiple regression analyses indicated that direction (42% of variance) was a better predictor of performance than intensity (22%).