Implicit attentional orienting in a target detection task with central cues

Studies using Posner’s spatial cueing paradigm have demonstrated that participants can allocate their attention to specific target locations based on the predictiveness of preceding cues. Four experiments were conducted to investigate attentional orienting processes operating in a high probability condition (cues 75% predictive) as compared to a low probability condition (cues 50% predictive) using various types of centrally-presented cues. Spatially-informative cues (arrows and circles with gaps) resulted in cueing effects (CEs) for both probability conditions, with significantly larger CEs in the high probability conditions than the low probability conditions. Participants in the high probability conditions reported little or no awareness of cue–target probabilities after task completion. Our results provide support for an implicit learning account of the proportion valid effect under experimental conditions involving spatially-informative central cues and relatively short stimulus onset asynchronies (SOAs).     

Win-shift and win-stay learning in the short-beaked echidna (<Emphasis Type="Italic">Tachyglossus aculeatus</Emphasis>)

Numerous previous investigators have explained species differences in spatial memory performance in terms of differences in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial memory performance of echidnas (or "spiny anteaters") can be understood in terms of the spatio-temporal distribution of their prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas were better able to learn to avoid a previously rewarding location (to "win-shift") than to learn to return to a previously rewarding location (to "win-stay"), at short retention intervals, but were unable to learn either of these strategies at retention intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval results do not. Electronic Publication     

Quality Instances and the Structure of the Concrete Particular

In this paper, I examine a puzzle that emerges from what J. P. Moreland has called the traditional realist view of quality instances. Briefly put, the puzzle is to figure out how quality instances fit into the overall structure of a concrete particular, given that the traditional realist view of quality instances prima facie seems incompatible with what might be called the traditional realist view of concrete particulars. After having discussed the traditional realist views involved and the puzzle that emerges from their juxtaposition, I propose an alternative realist view of quality instances which resolves the puzzle. In short, the puzzle is solved by treating the distinction between a concrete particular and its quality instances as a distinction of reason, and by adopting the view that the individuating element of a concrete particular must also serve as its unifying element – a view which Moreland, one of traditional realism’s most stalwart contemporary defenders, rejects.     

Sensitivity to number: Reply to Gebuis and Gevers

Past research showing a bias towards the larger non-symbolic number by adults and children in line bisection tasks (de Hevia & Spelke, 2009) has been challenged by Gebuis and Gevers, suggesting that area subtended by the stimulus and not number is responsible for the biases. I review evidence supporting the idea that although sensitivity to number might be relatively affected by visual cues, number is a major, salient property of our environment. The influence of non-numerical cues might be seen as the concurrent processing of dimensions that entail information of magnitude, without implying that number is constructed out of those dimensions.     

Plasticity of human spatial cognition: spatial language and cognition covary across cultures

The present paper explores cross-cultural variation in spatial cognition by comparing spatial reconstruction tasks by Dutch and Namibian elementary school children. These two communities differ in the way they predominantly express spatial relations in language. Four experiments investigate cognitive strategy preferences across different levels of task-complexity and instruction. Data show a correlation between dominant linguistic spatial frames of reference and performance patterns in non-linguistic spatial memory tasks. This correlation is shown to be stable across an increase of complexity in the spatial array. When instructed to use their respective non-habitual cognitive strategy, participants were not easily able to switch between strategies and their attempts to do so impaired their performance. These results indicate a difference not only in preference but also in competence and suggest that spatial language and non-linguistic preferences and competences in spatial cognition are systematically aligned across human populations.     

Paradoxical cross-over due to attention to high or low spatial frequencies

The mechanisms underlying the right hemisphere's dominance for spatial and attentional functions lacks a comprehensively explanation. For example, perceptual biases, as observed in line bisection and related tasks, might be caused by an attentional asymmetry or by perceptual processes such as a specialization of the left and right hemisphere for high and low spatial frequencies (SFs), respectively. Here we used the gratingscales task to measure perceptual bias in SF judgements, and we cued participants' attention either to high or low SFs. Participants showed a leftward bias when comparing the high SF components of the stimulus, and a rightward bias when comparing the low SF components-opposite to what would be expected from a hemispheric lateralization for SFs. Two control experiments used different strategies to manipulate the width of the attentional window. However, we observed no influence on perceptual bias, thus ruling out the possibility that the results in Experiment 1 were due to differences in attentional window size. These data support the idea of an attentional asymmetry underlying perceptual bias. Our results provide novel support for the role of attentional asymmetry in perceptual biases.     

When earning is beneficial for learning: The relation of employment and leisure activities to academic outcomes

The present study investigates the joint effect of the quantity and quality of out-of-school activities (i.e., employment and leisure) on academic outcomes (i.e., well-being, study attitude, and academic performance) among 230 undergraduates. A series of hierarchical regression analyses show that spending too much time in both employment and leisure activities has negative relations with undergraduates’ academic outcomes. Work-study interference fully mediated the effect of time engagement in student employment on students’ reported well-being. These findings support a conflict perspective on multiple role engagement. However, results also show positive effects of activities depending on job demand and autonomy and level of autonomous motivation to engage in these activities. We conclude that out-of-school activities can be beneficial for students’ academic outcomes and preparation for the labor market when perceived as relevant for their academic study and performed in a balanced, autonomous way.     

A computational model of spatial visualization capacity

Visualizing spatial material is a cornerstone of human problem solving, but human visualization capacity is sharply limited. To investigate the sources of this limit, we developed a new task to measure visualization accuracy for verbally-described spatial paths (similar to street directions), and implemented a computational process model to perform it. In this model, developed within the Adaptive Control of Thought-Rational (ACT-R) architecture, visualization capacity is limited by three mechanisms. Two of these (associative interference and decay) are longstanding characteristics of ACT-R’s declarative memory. A third (spatial interference) is a new mechanism motivated by spatial proximity effects in our data. We tested the model in two experiments, one with parameter-value fitting, and a replication without further fitting. Correspondence between model and data was close in both experiments, suggesting that the model may be useful for understanding why visualizing new, complex spatial material is so difficult.