Hinge versus twist: the effects of 'reference surfaces' and discontinuities on stereoscopic slant perception

Stereoscopic slant perception around a vertical axis (horizontal slant) is often found to be strongly attenuated relative to geometric prediction. Stereo slant is much greater, however, when an adjacent surface, stereoscopically in the frontal plane, is added. This slant enhancement is often attributed to the presence of a 'reference surface' or to a spatial change in the disparity gradient (introducing second and higher derivatives of disparity). Gillam, Chambers, and Russo (1988 Journal of Experimental Psychology: Human Perception and Performance 14 163-175) questioned the role of these factors in that placement of the frontal-plane surface in a direction collinear with the slant axis (twist configuration) sharply reduced latency for perceiving slant whereas placing the same surface in a direction orthogonal to the slant axis (hinge configuration) had little effect. We here confirm these findings for slant magnitude, showing a striking advantage for twist over hinge configurations. We also examined contrast slant measured on the frontal-plane surface in the hinge and twist configurations. Under conditions where test and inducer surfaces have centres at the same depth for twist and hinge, we found that twist configurations produced strong negative slant contrast, while hinge configurations produced significant positive contrast or slant assimilation. We conclude that stereo slant and contrast effects for neighbouring surfaces can only be understood from the patterns and gradients of step disparities present. It is not adequate to consider the second surface merely as a reference slant for the first or as having its effect via a spatial change in the disparity gradient.     

Hope and the Academic Trajectory of College Students

Previous longitudinal studies of student hope have established a connection between how people think about the future and their college achievement. This study examined the role of hope in predicting the achievement and retention of college students while controlling for educational history and two other psychological constructs, academic self-efficacy and engagement. Hope, self-efficacy, engagement were all correlated with both the number of semesters enrolled and cumulative grade point averages (GPAs) for the first 4 years of college. Hope was the only factor that had unique effects when examining predictors simultaneously and controlling for academic history. Hope uniquely predicted the number of enrolled semesters, whether students returned for the 2nd semester of college, whether students graduated in 4 years, and students’ GPAs across 4 years of college. Results therefore indicate that hope was the most robust predictor of academic achievement in college after controlling for educational history. These findings point to a need to help students develop the capacity to initiate and sustain movement toward goals in the pursuit of higher academic achievement.     

Overcoming Procrastination: The Effect of Implementation Intentions1

A hypothesized solution for procrastination is the formation of an implementation intention ( Van Eerde, 2000 ). University students (N = 152) were assessed using the Aitken Procrastination Inventory ( Aitken, 1982 ) and were asked to report to an experiment. Half of the participants formed implementation intentions to attend. An odds ratio indicated that participants who formed implementation intentions were nearly 8 times more likely to keep their appointments than those who did not. Low procrastinators reported more often for the experiment than did high procrastinators (Low = 49.4%; High = 30.1%), χ²(1, N = 152) = 5.84, p < .016. The interaction between implementation intentions and procrastination was not significant, χ²(1, N = 152) = 0.28, p < .60.     

Monotone Quantifiers Emerge via Iterated Learning

Natural languages exhibit many semantic universals, that is, properties of meaning shared across all languages. In this paper, we develop an explanation of one very prominent semantic universal, the monotonicity universal. While the existing work has shown that quantifiers satisfying the monotonicity universal are easier to learn, we provide a more complete explanation by considering the emergence of quantifiers from the perspective of cultural evolution. In particular, we show that quantifiers satisfy the monotonicity universal evolve reliably in an iterated learning paradigm with neural networks as agents.     

A note on ROC analysis and non-parametric estimate of sensitivity

In the signal detection paradigm, the non-parametric index of sensitivity A′, as first introduced by Pollack and Norman (1964), is a popular alternative to the more traditional d′ measure of sensitivity. Smith (1995) clarified a confusion about the interpretation of A′ in relation to the area beneath proper receiver operating characteristic (ROC) curves, and provided a formula (which he called A′′) for this commonly held interpretation. However, he made an error in his calculations. Here, we rectify this error by providing the correct formula (which we call A) and compare the discrepancy that would have resulted. The corresponding measure for bias b is also provided. Since all such calculations apply to “proper” ROC curves with non-decreasing slopes, we also prove, as a separate result, the slope-monotonicity of ROC curves generated by likelihood-ratio criterion.This revised article was published online in August 2005 with the PDF paginated correctly.     

Strength of affective reaction as a signal to think carefully

Analytic processes reduce biases, but it is not known how or when these processes will be deployed. Based on an affective signal hypothesis, relatively strong affective reactions were expected to result in increased analytic processing and reduced bias in judgement. The valence and strength of affective reactions were manipulated through varying outcomes in a game or evaluative conditioning of a stimulus. Relatively strong positive or negative affective reactions resulted in less desirability bias. Bias reduction only occurred if participants had time to deploy analytic processes and indicators of the degree of analytic processing (in the form of attentional control) predicted less bias. Affective processes have long been acknowledged as a source of bias, but these findings suggest affective processes are also integral to bias reduction.     

The Developmental Trajectory from Amodal Perception to Empathy and Communication: The Role of Mirror Neurons in This Process

In a recent paper entitled “Mirror Neurons. Procedural Learning and the Positive New Experience” (Wolf et al., 2000), data were presented about a special type of neuron, the mirror neuron, originally located by Rizzolatti and his colleagues (1995). These neurons were discussed as they related to a particular developmental view of psychoanalysis, developmental systems self psychology (Shane, Shane, and Gales. 1997).

In this paper, we focus on how this mirror neuron system might contribute to the development of communicative abilities in humans. First we summarize the research findings about mirror neurons and how they apply to humans. We then attempt to demonstrate how the mirror neuron system might be involved in a developmental sequence hypothesized by Kohut (1984), Stern (1985), and others to begin in infancy. We postulate that this trajectory starts with the onset of “amodal perception” (Stern, 1985) and then proceeds to affect resonance, joint attention, and ultimately to symbolization of language. In this paper, we attempt to integrate these concepts with a formulation of empathy and demonstrate what might go awry in developmental disorders when the normative sequence of development described above does not take place.