The tendency to overestimate what is visible in a planar mirror amongst adults and children

Adults hold several mistaken beliefs about simple mechanical and optical phenomena. In particular, many adults believe that they would be able to see their own image in a mirror before they are in front of it. Similarly, they expect objects to become visible in mirrors before they actually do. This overestimation of what is visible is known as the early error (Bertamini, Spooner, & Hecht, 2003). It has been suggested that incorrect models about mechanics, and therefore erroneous beliefs, develop over time, as evidenced by good performance in young children (Kaiser, McCloskey, & Proffitt, 1986). With respect to knowledge about what is visible in mirrors we report the first developmental data. We confirmed an effect for prospective University students but found no evidence of any early error in children between the age of 5 and 11. This erroneous belief about mirrors develops during the later school years when people develop a system of beliefs based on experience.     

The perceived structural shape of thin (wire-like) objects is different from that of silhouettes

Observers are faster at judging the position of convex vertices compared to concave vertices. This is believed to be due to an explicit representation of position for visual parts. The best evidence comes from comparing the same contours perceived as either figures or holes, because this is a pure figure ground reversal (Bertamini and Croucher, 2003 Cognition 87 33 - 54; Bertamini and Mosca, 2004 Perception 33 35-48). Specifically, an interaction is present between type of object (object or hole) and shape. One assumption is that the contour of a silhouette is perceived as the rim of a solid object. It follows that a different pattern should be found for thin (wire-like) objects compared to silhouettes. We confirm this difference in three experiments. We argue that this is due to the perceived parts when contours can be interpreted as self-occlusion rims.     

Acquisition, retention, and recall of memory after injection of RS67333, a 5-HT(4) receptor agonist, into the nucleus basalis magnocellularis of the rat

The serotonin 5-HT4 subtype receptor is predominantly localized into anatomical structures linked to memory and cognition. A few experimental studies report that the acute systemic administration of selective 5-HT4 agonists has ameliorative effects on memory performance, and that these effects are reversed by contemporary administration of 5-HT4 receptor antagonists. To verify whether this procognitive action occurs via the activation of the cholinergic nucleus basalis magnocellularis (NBM)-cortical pathways, we examined the effects of RS67333, a selective partial agonist of the 5-HT4 receptor, on rat performance in a place recognition task upon local administration of the drug into the NBM area. The intra-NBM administration of RS67333 enhances the acquisition (200-500 ng/0.5 microL) and the consolidation (40-200 ng/0.5 microL) of the place recognition memory. These effects are reversed by pretreatment with the selective 5-HT4 receptor antagonist RS39604 (300 ng/0.5 microL). Conversely, the recall of memory is not affected by the 5-HT4 agonist. Our results indicate that 5-HT4 receptors located within the NBM may play a role in spatial memory and that the procognitive effect of RS67333 is due, at least in part, to the potentiation of the activity of cholinergic NBM-cortical pathways.     

Automatic spatial coding of perceived gaze direction is revealed by the Simon effect

In a typical Simon task, the (irrelevant) spatial position of the stimulus interferes with the processing of the salient characteristic (e.g., color). We used the Simon effect to investigate the automatic processing of gaze cues. We show that a simple drawing of schematic eyes automatically generates a spatially defined code of gaze direction. Although completely irrelevant to the task, direction of gaze influenced reaction times in a spatially selective two-choice discrimination based on eye color. Moreover, in one experiment employing an orthogonal manipulation of stimulus position and gaze direction, we found that coding of gaze direction is independent of stimulus spatial coding. Our finding of a “gazedirection Simon effect” is congruent with the hypothesis that gaze direction is coded by a specialized mechanism.     

The shape of holes

The shape of holes can be recognized as accurately as the shape of objects (Palmer, S. E. (1999). Vision science: photons to phenomenology. Cambridge, MA: MIT Press), yet the area enclosed by a hole is a background region, and it can be demonstrated that background regions are not represented as having shape. What is therefore the shape of a hole, if any? To resolve this apparent paradox, we suggest that the shape of a hole is available indirectly from the shape of the surrounding object. We exploited the fact that observers are faster at judging the position of convex vertices than concave ones (Perception 30 (2001) 1295), and using a figural manipulation of figure/ground we found a reversal of the relative speeds when the same contours were presented as holes instead of objects. If contours were perceived as belonging to the hole rather than the surrounding object then there would have been no qualitative difference in responses to the object and hole stimuli. We conclude that the contour bounding a hole is automatically assigned to the surrounding object, and that a change in perception of a region from object to hole always drastically changes the encoded information. We discuss the many interesting aspects of holes as a subject of study in different disciplines and predict that much insight especially about shape will continue to come from holes.     

Psychache and suicidality in adult mood disordered outpatients in Brazil

Shneidman (e.g., 1998) has theorized that psychache--general psychological and emotional pain that reaches intolerable intensity--is an important suicide-related variable, and indeed, represents a source of suicidal behavior. This conceptualization, while prominent and clinically and intuitively appealing, has received relatively little empirical scrutiny. In this study, we determined whether an index closely related to psychache, psychological quality of life, would display a special and resilient association to suicidality among 60 adult psychiatric outpatients in Brazil. All patients underwent structured clinical interviews and completed various clinical and quality-of-life measures. We found that the association between psychological quality of life and suicidality remained, even when depression, hopelessness, and other domains of quality of life were controlled. Psychache appears to deserve its place among key suicide-related variables, and deserves the attention of clinicians working with suicidal people.     

Early mother-infant interaction during breast- and bottle-feeding

Thirty-two primiparous mothers with their neonates, 20 breast-fed and 12 bottle-fed, were videotaped during feeding longitudinally (at 3, 10 days, 1 and 3 months) in order to investigate whether patterns of mother-infant interaction observed during breast- and bottle-feeding differ also for behavior not directly related to sucking. Infant state, sucking behavior, mother behavior and mother-infant interaction were analyzed by both sequential and non sequential analysis. Results suggest that the method of feedings affects mother-infant interaction observed during and just after feeding also for some behavior not directly related to sucking. The percentage of mutual touch, tactile stimulation and mother's gaze to infant was significantly more elevated during breast-feeding. Independently of the feeding mode, significant sequential dependencies between infant state of alertness and auditory stimulation, and auditory stimulation and mutual gaze were found.     

The Role of Temporal Comparison, Social Comparison, and Direct Appraisal in the Elderly's Self-Evaluations of Health

Elderly persons (n= 91) were interviewed about self- perceptions of physical health and the contribution of social comparison, temporal comparison, and direct appraisal to these judgments. Consistent with previous studies, self-assessments tended to be mainly positive (67% reported their health as “good” or “excellent”), though tempered somewhat by the individual's objective physical condition (i.e., number of chronic diseases or disabilities). Independent of objective health, respondents' ratings were more negative if they mentioned thinking about past or anticipated health. Respondents were more concerned about their health if they thought about their past or anticipated health or mentioned comparing with a specific other person. Direct feedback had no effect on health ratings. Among those who reported social comparison, ratings were more positive when worse-off others were mentioned. Temporal comparisons may be associated with more negative ratings because the elderly's past health is likely to have been better and their future (anticipated) health can be expected to become worse. If using temporal and social comparison information is associated with more negative assessments then what accounts for the generally positive self-assessments? We propose that the elderly compare themselves with a cognitively constructed stereotypical standard of the frail elderly rather than with a specific other. Because few elderly actually “fit” this stereotype, most elderly feel they are doing well.     

Social information facilitates learning about novel food sources in adult flower-visiting bats

Animal Cognition - Incorporating novel food sources into their diet is crucial for animals in changing environments. Although the utilization of novel food sources can be learned individually,...