Processing convexity and concavity along a 2-D contour: figure–ground, structural shape, and attention

Interest in convexity has a long history in vision science. For smooth contours in an image, it is possible to code regions of positive (convex) and negative (concave) curvature, and this provides useful information about solid shape. We review a large body of evidence on the role of this information in perception of shape and in attention. This includes evidence from behavioral, neurophysiological, imaging, and developmental studies. A review is necessary to analyze the evidence on how convexity affects (1) separation between figure and ground, (2) part structure, and (3) attention allocation. Despite some broad agreement on the importance of convexity in these areas, there is a lack of consensus on the interpretation of specific claims—for example, on the contribution of convexity to metric depth and on the automatic directing of attention to convexities or to concavities. The focus is on convexity and concavity along a 2-D contour, not convexity and concavity in 3-D, but the important link between the two is discussed. We conclude that there is good evidence for the role of convexity information in figure–ground organization and in parsing, but other, more specific claims are not (yet) well supported.     

Perceptual and motor congruency effects in time–space association

It is well established that temporal events are represented on a spatially oriented mental time line from left to right. Depending on the task characteristics, the spatial representation of time may be linked to different types of dimensions, including manual response codes and physical space codes. The aim of the present study was to analyze whether manual response and physical space codes are independent of each other or whether they interact when both types of information are involved in the task. The participants performed a temporal estimation task with two lateralized response buttons in four experiments. In the first experiment, the target stimuli were presented on the left side, at the center, or on the right side of the space, whereas the reference stimuli were always presented centrally. The reverse situation was presented in the second experiment. In the third experiment, both stimuli were presented in opposite spatial positions (e.g., left–right), whereas in the last experiment, both stimuli were presented in the same spatial position (e.g., left–left). In all experiments, perceptual and motor congruency effects were found, but no modulation of the congruency effects was found when both the perceptual and motor components were congruent. The results indicated that physical, spatial, and manual response codes are independent from each other for time–space associations, even when both codes are involved in the task. These results are discussed in terms of the “intermediate-coding” account.     

All Against All: How Beliefs about Human Nature Shape Foreign Policy Opinions

Although the American public's increasingly cynical views about human nature have drawn considerable attention from scholars, existing research says little about how interpersonal trust shapes mass foreign policy opinions. This study analyzes survey data to test the claim that citizens use their beliefs about human nature to reason about international affairs. The results indicate that cynical citizens are more likely than trusting citizens to endorse the principle of isolationism and to oppose cooperative forms of intervention in other nations' problems. Citizens' use of interpersonal trust as an information shortcut helps them to make inferences regarding a topic about which they typically know little, but such inferences are not necessarily realistic ones.     

Sample size, confidence, and contingency judgement.

According to statistical models, the acquisition function of contingency judgement is due to confidence increasing with sample size. According to associative models, the function reflects the accumulation of associative strength on which the judgement is based. Which view is right? Thirty university students assessed the relation between a fictitious medication and a symptom of skin discoloration in conditions that varied sample size (4, 6, 8 or 40 trials) and contingency (delta P = .20, .40, .60 or .80). Confidence was also collected. Contingency judgement was lower for smaller samples, while confidence level correlated inversely with sample size. This dissociation between contingency judgement and confidence contradicts the statistical perspective.     

Risk Factors for Attempting Suicide in Prisoners

We wished to examine determinants of suicidal behavior in prisoners. 903 male prisoners had a psychiatric interview which included various psychometric tests. Suicide attempters were compared with prisoners who had never attempted suicide. Significantly more of the attempters had a history of psychiatric disorder, substance abuse, a family history of suicidal behavior, convictions for violent crime, had exhibited aggressive behavior in jail, and had higher BGLHA aggression scores. A similar pattern of risk factors was found for prisoners with suicidal ideation. A lifetime history of attempting suicide, or of having suicidal ideation, is frequent in prisoners. Risk factors include family, developmental, aggression, personality, psychiatric, and substance abuse factors.     

Laterality effects in the spinning dancer illusion: The viewing‐from‐above bias is only part of the story

The ‘silhouette illusion’, representing the silhouette of a female dancer pirouetting about her vertical axis, is a bistable stimulus created by Japanese web designer Nobuyuki Kayahara. Although the dancer can be perceived as spinning either clockwise or counterclockwise, the clockwise rotation is usually preferred. Troje and McAdam (i‐Perception, 2010, 1, 143) showed that this clockwise bias can be attributed to the tendency to assume a viewpoint from above rather than from below, given that the dancer is portrayed from a vantage point that is not perpendicular to the axis of rotation. Here, we tested whether another possible factor contributing to the observers’ interpretation of this bistable stimulus might be the tendency to perceive movements of the right rather than the left foot. We confirmed both the viewing‐from‐above bias and our hypothesis. The bias to perceive movements of the right leg might be a generalization to lower limbs of a perceptual frequency effect already observed for upper limbs. Such a perceptual and attentional bias towards the right hand/foot could account for the greater ability to predict the outcome of sport actions when observing right‐ rather than left‐limbed movements, and thus the left‐handers' and left‐footers' advantage observed in a variety of interactive sports.     

Are Arithmetic Networks Interdependent In Number-Matching Task?

Addition and multiplication facts are retrieved from a network-like structure, as shown by data from number-matching tasks. Even if several evidences (e.g., cross-operation confusion effect) suggest that these networks are interrelated, the interdependency between addition and multiplication networks could be influenced by the type of task used (e.g., verification task). The present study aimed to investigate whether the addition and multiplication networks were interdependent or separate using a number-matching task. Eighty participants were divided in four groups. The Groups A (x, x, x) and B (+, +, +) performed the task in which only one arithmetic interference effect was implemented through three sessions (pure condition). The Groups C (x, x, +) and D (+, +, x) performed the same task in which the same arithmetic interference effect appeared in the first and second sessions, while a different arithmetic problem was presented in the last session (mixed condition). In the last session, the interference effect in the mixed condition was higher than that in the pure condition. The results argued more for an independency of addition and multiplication networks than for their interdependency.     

Spontaneous non‐verbal counting in toddlers

A wealth of studies have investigated numerical abilities in infants and in children aged 3 or above, but research on pre‐counting toddlers is sparse. Here we devised a novel version of an imitation task that was previously used to assess spontaneous focusing on numerosity (i.e. the predisposition to grasp numerical properties of the environment) to assess whether pre‐counters would spontaneously deploy sequential (item‐by‐item) enumeration and whether this ability would rely on the object tracking system (OTS) or on the approximate number system (ANS). Two‐and‐a‐half‐year‐olds watched the experimenter performing one‐by‐one insertion of ‘food tokens’ into an opaque animal puppet and then were asked to imitate the puppet‐feeding behavior. The number of tokens varied between 1 and 6 and each numerosity was presented many times to obtain a distribution of responses during imitation. Many children demonstrated attention to the numerosity of the food tokens despite the lack of any explicit cueing to the number dimension. Most notably, the response distributions centered on the target numerosities and showed the classic variability signature that is attributed to the ANS. These results are consistent with previous studies on sequential enumeration in non‐human primates and suggest that pre‐counting children are capable of sequentially updating the numerosity of non‐visible sets through additive operations and hold it in memory for reproducing the observed behavior.     

Positive Feelings at School: On the Relationships Between Students’ Character Strengths,School-Related Affect,and School Functioning

The present study was designed to examine the relationships between students’ character strengths, school-related affect, positive school functioning (i.e., motivation to learn, interest, and engagement at class), and school achievement following the “engine model of well-being” that is focusing on inputs (e.g., personality traits), processes (e.g., moods, emotions), and outcomes (e.g., engagement, accomplishments) within the context of well-being research. A sample of 196 children completed the Values in Action Inventory of Strengths for Youth, which assesses 24 character strengths, and the PANAS-C that assesses school-related positive and negative affect. Additionally, homeroom teachers rated students’ positive school functioning (i.e., motivation, engagement, and interest at school) and their overall school achievement. The character strengths of zest, love of learning, perseverance, and social intelligence showed the strongest positive correlations with school-related positive affect. Teamwork, hope, self-regulation, and love were substantially negatively correlated with school-related negative affect. Certain character strengths showed positive relationships with positive school functioning and overall school achievement. A path model, testing the “engine model of well-being”, found—additionally to direct effects—indirect relationships between character strengths and positive school functioning (through school-related positive affect), which in turn leads to higher school achievement. The presented findings show character strengths as meaningful resources in the schooling context. Character strengths emerge to be crucial for students to experience school-related positive affect, which in turn supports students’ positive school functioning and their overall school achievement. The results demonstrate the complex interplay between students’ personality traits, affect, school functioning, and achievement at school.