Object detection in natural scenes: Independent effects of spatial and category-based attention

Humans are remarkably efficient in detecting highly familiar object categories in natural scenes, with evidence suggesting that such object detection can be performed in the (near) absence of attention. Here we systematically explored the influences of both spatial attention and category-based attention on the accuracy of object detection in natural scenes. Manipulating both types of attention additionally allowed for addressing how these factors interact: whether the requirement for spatial attention depends on the extent to which observers are prepared to detect a specific object category—that is, on category-based attention. The results showed that the detection of targets from one category (animals or vehicles) was better than the detection of targets from two categories (animals and vehicles), demonstrating the beneficial effect of category-based attention. This effect did not depend on the semantic congruency of the target object and the background scene, indicating that observers attended to visual features diagnostic of the foreground target objects from the cued category. Importantly, in three experiments the detection of objects in scenes presented in the periphery was significantly impaired when observers simultaneously performed an attentionally demanding task at fixation, showing that spatial attention affects natural scene perception. In all experiments, the effects of category-based attention and spatial attention on object detection performance were additive rather than interactive. Finally, neither spatial nor category-based attention influenced metacognitive ability for object detection performance. These findings demonstrate that efficient object detection in natural scenes is independently facilitated by spatial and category-based attention.     

Measuring voting power for dependent voters through causal models

We construct a new measure of voting power that yields reasonable measurements even if the individual votes are not cast independently. Our measure hinges on probabilities of counterfactuals, such as the probability that the outcome of a collective decision would have been yes, had a voter voted yes rather than no as she did in the real world. The probabilities of such counterfactuals are calculated on the basis of causal information, following the approach by Balke and Pearl. Opinion leaders whose votes have causal influence on other voters’ votes can have significantly more voting power under our measure. But the new measure of voting power is also sensitive to the voting rule. We show that our measure can be regarded as an average treatment effect, we provide examples in which it yields intuitively plausible results and we prove that it reduces to Banzhaf voting power in the limiting case of independent and equiprobable votes.     

The rich are different: Unravelling the perceived and self‐reported personality profiles of high‐net‐worth individuals

Beyond money and possessions, how are the rich different from the general population? Drawing on a unique sample of high‐net‐worth individuals from Germany (≥1 million Euro in financial assets; N = 130), nationally representative data (N = 22,981), and an additional online panel (N = 690), we provide the first direct investigation of the stereotypically perceived and self‐reported personality profiles of high‐net‐worth individuals. Investigating the broad personality traits of the Big Five and the more specific traits of narcissism and locus of control, we find that stereotypes about wealthy people's personality are accurate albeit somewhat exaggerated and that wealthy people can be characterized as stable, flexible, and agentic individuals who are focused more on themselves than on others.     

Short-term memory after all: comment on Sederberg, Howard, and Kahana (2008)

P. B. Sederberg, M. W. Howard, and M. J. Kahana have proposed an updated version of the temporal-context model (TCM-A). In doing so, they accepted the challenge of developing a single-store model to account for the dissociations between short- and long-term recency effects that were reviewed by E. J. Davelaar, Y. Goshen-Gottstein, A. Ashkenazi, H. J. Haarmann, and M. Usher (2005). In this commentary, the authors argue that the success of TCM-A in addressing the dissociations is dependent not only on an episodic encoding matrix but--critically--also on its implicit use of a short-term memory store--albeit exponential rather than buffer-like. The authors also highlight some difficulties of TCM-A in accounting for these dissociations, and they argue that TCM-A fails to account for critical data--the presentation-rate effect--that dissociates exponential and buffer-like models.     

Religious Schools and Discipline

Recently there has been a growing interest in faith-based schools (see e.g. The Times , No. 67060, 2 December 2001, pp. 1, 4). Politicians have indicated a willingness to support such schools on the assumption that religion may make a positive contribution to schooling. It is not at all self-evident that there is a clear inter-relationship between religion and education on which the assumption can be grounded. In what follows I shall seek to explore one sphere in which religion can have a bearing on schooling, notably on its understanding and practice of discipline. Before the specifically religious impact can be explored, the complex nature of discipline and reward/punishment in school is examined. The philosophy of behaviourism is rejected as inadequate for the processes of education, not least because of the insights of Nietzsche and Plato. The analysis leads to the identification of three very distinct forms of discipline, namely, authoritarian, moral and 'Socratic'. Whilst in practice schools may resort to all three, they would not necessarily do so in a coherent way as the authoritarian and moral forms of discipline are, in important respects, incompatible. The understanding of what religion is, is also shown to be of a varied nature. Differing views and features of religion can serve to reinforce the school as an authoritarian, moral or 'Socratic' community. Whilst the inherent authoritarianism of religion and the ethical dimension of religion are well known, a 'Kierkegaardian' view of religion would have strong affinities with 'Socratic' discipline and help to support the view of the school as a community for all.     

Temperance: with a consideration of evil,violence, and pedagogy

The article investigates the meaning of temperance by noting some cultural assumptions, raising the question as to why this classical virtue has largely disappeared from modern ethical discourse. By means of some historical notes temperance is identified as the unifying virtue in the person and in society. In its Christian form it is related to love of the transcendent goal of human life. By being similarly goal driven, education should consider the cardinal virtues and celebrate them through worship.     

Visual pattern matching: Effects of size ratio, complexity, and similarity in simultaneous and successive matching

An experiment on mental transformation of size, in pairwise comparison of simultaneously or successively presented figures with respect to shape, is reported. Regardless of type of presentation (simultaneous vs. successive), figural complexity, and similarity within pairs of different-shaped figures, median latencies of both same and different responses were approximately linearly increasing functions of the linear size ratio between the patterns to be compared. The slopes of the functions showed significant effects of figural complexity and similarity for simultaneous but not for successive matching. The results suggest that successive matching was done by encoding a subpattern of the first stimulus in a pair as a mental image, transforming the image to the size format of the other stimulus, and then testing for a match; in simultaneous matching the process of encoding, transformation, and comparison appeared to be executed several times for each pair of figures. The interpretation was illustrated by a random walk model, which provided a good fit to the results. Received: 31 March 1998 / Accepted: 22 August 1998     

Single-letter recognition as a function of exposure duration

The time course of visual letter recognition was investigated in a single-stimulus identification experiment. On each trial, a randomly chosen stimulus letter was presented at 1 of 12 equiprobable positions that were equally spaced around the circumference of an imaginary circle centered on fixation. Exposure duration was varied from 10 to 200 ms, and the letter was followed by a pattern mask. The subject's task was to report the identity of the stimulus letter but refrain from guessing. For the briefest exposures, correct reports never occurred. For longer exposures, the function relating the probability p of recognizing the letter to the duration t of the stimulus exposure was well approximated by an exponential distribution function: p(t) = 1 − exp[−v·(t−t ₀)], where v is the rate of processing and t ₀ is the minimum effective exposure duration. The generality of this finding may be limited to cases in which stimuli are highly discriminable and response criteria are conservative. Extensions to Poisson counter or random walk models are considered for cases in which stimuli are confusable. Received: 1 July 1997 / Accepted: 2 July 1998     

Anatomy of a decision: striato-orbitofrontal interactions in reinforcement learning, decision making, and reversal

The authors explore the division of labor between the basal ganglia-dopamine (BG-DA) system and the orbitofrontal cortex (OFC) in decision making. They show that a primitive neural network model of the BG-DA system slowly learns to make decisions on the basis of the relative probability of rewards but is not as sensitive to (a) recency or (b) the value of specific rewards. An augmented model that explores BG-OFC interactions is more successful at estimating the true expected value of decisions and is faster at switching behavior when reinforcement contingencies change. In the augmented model, OFC areas exert top-down control on the BG and premotor areas by representing reinforcement magnitudes in working memory. The model successfully captures patterns of behavior resulting from OFC damage in decision making, reversal learning, and devaluation paradigms and makes additional predictions for the underlying source of these deficits.