The pursuit of Leonardo's constraint

Leonardo da Vinci (1452-1519) identified two stimulus situations that cannot be painted faithfully on a canvas: (a) when two objects are located in the same direction with respect to the painter's head, and (b) when parts of a surface are visible to one eye, but occluded from the other eye. He analysed these situations in terms of rays being emitted from the two eyes and, aside from the origin of the rays, the projective geometry he used was correct. His analyses showed that what can be seen from two vantage points cannot be represented on a canvas, because a 'correct' painting must be created from a single 'station point'. He was struck by the consequence of this fact that the depth seen on a canvas cannot match that of viewing the scene with two eyes. Subsequent visual scientists focused on Leonardo's observation about the lack of vivid depth in a picture. We argue that a complete understanding of what we see in the two stimulus situations requires consideration of visual direction in addition to visual depth. More specifically, we argue that the visual directions of the two objects, (a) above, and the visual direction of the monocular areas, (b) above, are dependent upon the constraint that two opaque objects cannot be represented in the same direction. Demonstrations that readers can perform, and that support this argument, are provided on the Perception website at http://www.perceptionweb.com/perc0102/ono.html.     

A model of dual attitudes

When an attitude changes from A1 to A2, what happens to A1? Most theories assume, at least implicitly, that the new attitude replaces the former one. The authors argue that a new attitude can override, but not replace, the old one, resulting in dual attitudes. Dual attitudes are defined as different evaluations of the same attitude object: an automatic, implicit attitude and an explicit attitude. The attitude that people endorse depends on whether they have the cognitive capacity to retrieve the explicit attitude and whether this overrides their implicit attitude. A number of literatures consistent with these hypotheses are reviewed, and the implications of the dual-attitude model for attitude theory and measurement are discussed. For example, by including only explicit measures, previous studies may have exaggerated the ease with which people change their attitudes. Even if an explicit attitude changes, an implicit attitude can remain the same.     

Visual neuroscience before the neuron

Visual neuroscience is considered to be a contemporary concern, based in large part on relating characteristics of neural functioning to visual experience. It presupposes a detailed knowledge of neural activity for which the neuron doctrine is a fundamental tenet. However, long before either the neuron doctrine had been advanced or the nerve cell had been described, attempts were made to estimate the dimensions of nerve fibres from measures of visual resolution. In the seventeenth century, the microscopes of Hooke and van Leeuwenhoek were unable to resolve structures as small as nerves adequately. However, it was not Hooke's microscope that led to an estimate of the dimensions of nerve fibres but his experiments on the limits of visual resolution. Hooke determined that a separation of one minute of arc was the minimum that could normally be seen. Descartes had earlier speculated that the retina consisted of the terminations of fibres of the optic nerve, and that their size defined the limits of what could be seen. Estimates of the diameters of nerve fibres were made on the basis of human visual acuity by Porterfield in 1738; he calculated the diameters of nerve fibres in the retina as one 7200th part of an inch (0.0035 mm), based on the resolution of one minute of arc as the minimum visible. In the same year, Jurin questioned the reliability of such estimates because of variations in visual resolution with different stimuli. The measurement of visual acuity was refined by Mayer in 1755, with dots, gratings, and grids used as stimuli. In the 1830s, Treviranus fused the microscopic and acuity approaches to determine the dimensions of nerve fibres. His indirect estimates of the dimensions of retinal fibres were close to those derived from microscopic observation. However, the suggestion that the retina consisted of terminations of nerve fibres influenced his detailed illustrations of its microscopic structure. Contrary to the situation that obtained after the microscopic structure of the retina had been established, a function of vision (acuity) was used to determine the dimensions of the structures (retinal elements) that were thought to mediate it.     

Dodge-ing the issue: Dodge,Javal, Hering,and the measurement of saccades in eye-movement research

Dodge, in 1916, suggested that the French term 'saccade' should be used for describing the rapid movements of the eyes that occur while reading. Previously he had referred to these as type I movements. Javal had used the term 'saccade' in 1879, when describing experiments conducted in his laboratory by Lamare. Accordingly, Javal has been rightly credited with assigning the term to rapid eye movements. In English these rapid rotations had been called jerks, and they had been observed and measured before Lamare's studies of reading. Rapid sweeps of the eyes occur as one phase of nystagmus; they were observed by Wells in 1792 who used an afterimage technique, and they were illustrated by Crum Brown in 1878. Afterimages were used in nineteenth-century research on eye movements and eye position; they were also employed by Hering in 1879, to ascertain how the eyes moved during reading. In the previous year, Javal had employed afterimages in his investigations of reading, but this was to demonstrate that the eyes moved horizontally rather than vertically. Hering's and Lamare's auditory method established the discontinuous nature of eye movements during reading, and the photographic methods introduced by Dodge and others in the early twentieth century enabled their characteristics to be determined with greater accuracy.     

Lay Theories Concerning Causes and Treatment of Depression

This study compared perceptions of the causes of, therapies for, and means of coping with, depression between two groups of currently nondepressed adults: one with a history of major depression and one with no history of depression. Currently nondepressed participants were selected so that effects of past experience of depression could be distinguished from those of current mood. Recovered depressed participants (RD) (n = 25) and Never depressed participants (ND) (n = 25) recruited via newspaper advertisements completed self-report measures of (a) the perceived utility of either professional or self-help coping strategies for managing their own experiences of depression; (b) likely effectiveness of several major therapies for depression; and (c) perceived accuracy of several etiological theories of depression. RD participants rated depression as being less amenable to everyday self-help methods of coping and more in need of professional intervention. However, RD and ND subgroups did not differ significantly in their perceptions of the plausibility of etiological theories of depression in general, nor in their ratings of the likely helpfulness of major therapies.     

Are Men Better Leaders? An Investigation of Head Coaches’ Gender and Individual Players’ Performance in Amateur and Professional Women’s Basketball

Male-dominated industries such as sport contain stereotypical and subjective notions of leadership ability (Burton et al. 2009; Fink 2008). These gender stereotypes often manifest themselves within varying levels of leadership, but specific to the sport industry, they are the most visible within the head coach role. Men hold the majority of head coach positions within the professional and amateur levels of sport, and these hiring practices can be based on gender-role stereotypes (Acosta and Carpenter 2014). In an attempt to challenge stereotypical gender based leadership preferences, leadership ability and performance should be objectively examined. Therefore, in the present investigation we aimed to examine the presence of gender stereotypes in the sport industry by determining whether the gender of a head coach for two women’s basketball leagues, the Women’s National Basketball Association (WNBA) and the National Intercollegiate Athletic Association (NCAA), impacted individual player performance. Data were collected for 1522 players for 19 WNBA seasons (1997–2015) and 4000 players for three seasons of NCAA Women’s Basketball (2013–2016). Results indicated that head coach gender does not appear to impact individual player performance in the WNBA or in the NCAA thereby providing objective evidence to challenge the traditional gender stereotypes found within the sports industry.     

Peer Toy Play as a Gateway to Children’s Gender Flexibility: The Effect of (Counter)Stereotypic Portrayals of Peers in Children’s Magazines

Extensive evidence has documented the gender stereotypic content of children’s media, and media is recognized as an important socializing agent for young children. Yet, the precise impact of children’s media on the endorsement of gender-typed attitudes and behaviors has received less scholarly attention. We investigated the impact of stereotypic and counter-stereotypic peers pictured in children’s magazines on children’s gender flexibility around toy play and preferences, playmate choice, and social exclusion behavior (n?=?82, age 4–7 years-old). British children were randomly assigned to view a picture of a peer-age boy and girl in a magazine playing with either a gender stereotypic or counter-stereotypic toy. In the stereotypic condition, the pictured girl was shown with a toy pony and the pictured boy was shown with a toy car; these toys were reversed in the counter-stereotypic condition. Results revealed significantly greater gender flexibility around toy play and playmate choices among children in the counter-stereotypic condition compared to the stereotypic condition, and boys in the stereotypic condition were more accepting of gender-based exclusion than were girls. However, there was no difference in children’s own toy preferences between the stereotypic and counter-stereotypic condition, with children preferring more gender-typed toys overall. Implications of the findings for media, education, and parenting practices are discussed, and the potential for counter-stereotypic media portrayals of toy play to shape the gender socialization of young children is explored.