Biomedical subjects

Susanne Huber

Publications and source records attributed to Susanne Huber.

7 recordsLinked to original sources

PubMed2006

Controlling reaching movements with predictable and unpredictable target motion in 10-year-old children and adults.

We investigated interception behavior in adults and 10-year-old children. Participants had to intercept virtual targets moving on either a predictable (linear) or unpredictable (non-linear) path (with random direction changes). Targets moved at two different velocities, which varied randomly from trial to trial. Participants reached for the targets via a force-feedback device. Reaching movements for linearly moving targets in a block of linearly moving targets were compared with reaching movements for linearly moving targets in the context of non-linearly moving targets. Movement direction and maximum speed of the first sub-movement were analyzed as well as frequency of target hits and number of sub-movements. Unpredictable target motion caused faster movement speeds than predictable target motion for both children and adults. Additionally, unpredictable target motion caused children and adults to gear their initial movement direction further towards the current position of the target, while with predictable target motion, they geared their initial movement direction further ahead of the target towards an anticipated interception position. Together, these results suggest differential processing of predictable and unpredictable object behavior in an interception task, and that this differential processing is already in place in 10-year-olds.

Adult↗

PubMed2006

Gaze behaviour in hereditary prosopagnosia.

Prosopagnosia is the inability to recognize someone by the face alone in the absence of sensory or intellectual impairment. In contrast to the acquired form of prosopagnosia we studied the congenital form. Since we could recently show that this form is inherited as a simple monogenic trait we called it hereditary form. To determine whether not only face recognition and neuronal processing but also the perceptual acquisition of facial information is specific to prosopagnosia, we studied the gaze behaviour of four hereditary prosopagnosics in comparison to matched control subjects. This rarely studied form of prosopagnosia ensures that deficits are limited to face recognition. Whereas the control participants focused their gaze on the central facial features, the hereditary prosopagnosics showed a significantly different gaze behaviour. They had a more dispersed gaze and also fixated external facial features. Thus, the face recognition impairment of the hereditary prosopagnosics is reflected in their gaze behaviour.

Adult↗

PubMed2005

Gaze behavior in analytical and holistic face processing.

We conducted two experiments examining children's and adults' gaze behavior when processing faces analytically (focusing on a single feature) or holistically (comparing the overall similarity of the faces). Children 6-8 and 9-10 years of age and adults were instructed to assign schematically drawn faces in Experiment 1 and photos of real faces in Experiment 2 to two categories. The categories were constructed so as to allow either an analytical or holistic categorization of the faces. During all trials, gaze behavior was recorded from stimulus onset until reaction. The location and duration of the fixations used were analyzed. Whereas the holistic processors fixated the whole area of the eyes and nose most and longest independently of age, analytical processors showed a more feature-specific gaze behavior, focusing their fixations upon the particular feature used for subsequent processing. Thus, differences in analytical and holistic face processing can be detected early in gaze behavior-that is, at the visual encoding stage.

Adolescent↗

PubMed2005

Academic mothers have a pronounced seasonal variation in their offspring sex ratio.

OBJECTIVES: Environmental and socio-demographic factors can influence the variation of the human sex ratio at birth (SRB = the ratio of males to males plus females). In particular, findings of seasonal, parental education, birth order, and maternal age effects on the SRB are not always in agreement, and a number of works report minimal variation. SETTING: Here, we investigated the seasonality of SRB in academic and non-academic mothers employed at the University of Vienna, and who gave birth between 1963 and 2000 (n = 1932 births). METHODS: All data were available from an anonymous employee database. RESULTS: Both groups, academic and non-academic mothers do not differ between their overall SRB. In academic mothers the SRB is significantly (P = 0.004) increased during the springtime and decreased during the summertime. Although in non-academic mothers the trend is comparable, it is far less pronounced and not significant (P = 0.345). When a multiple logistic model was applied to the data of academic mothers the only significant influencing factor on the SRB is the season, while birth order of children and mothers' age at childbirth has no effect. None of the three independent variables influence the SRB in non-academic mothers. MAIN FINDINGS: These findings suggest a more flexible SRB rate in academic mothers than in non-academics within the seasons. CONCLUSION: We conclude that the significant seasonal variation of the SRB in academic women cannot be merely interpreted as an effect of socio-economic status but more likely as the interaction between socio-economic and environmental working conditions.

Austria↗

PubMed2004

The role of characteristic motion in object categorization.

We report three experiments where we investigated the role of movement in object recognition. Previous studies have suggested a distinct and separate mechanism for object motion encoding, related to the action or motor-based system. To date, however, the role of an object's motion in long-term memory representations has not been explicitly tested. Here we were specifically interested in whether an object's characteristic motion patterns are integrated with static properties in an object's representation in memory. To that end, we used a simple categorization task where novel objects were categorized on the basis of two static (color and shape) and two dynamic (action and path) properties. The "action" of an object referred to its intrinsic motion pattern, whereas "path" referred to an object's extrinsic motion pattern (i.e., the route an object took). In Experiment 1, we found that all properties were relevant for categorization with the exception of path. This result was not due to path being less salient than other properties (Experiment 2). In Experiment 3, we found that when the action property was redundant that path was now used for categorization, suggesting that path was not used with action in Experiment 1 because of temporal order effects. Our findings argue for a cue-integrated model of object representation in memory.

Adolescent↗

PubMed2004

When is the ball going to hit the ground? Duration estimates, eye movements, and mental imagery of object motion.

Performance in 2 versions of a computer-animated task was compared. Participants either indicated the time of arrival of a target that rolled off a horizontal surface and fell--hidden from view--onto a landing point (production task) or judged flight time on a rating scale (judgment task). As predicted, performance was significantly better in the production task (Experiment 1), in which imagery of object motion probably replaced reasoning processes. Participants who exhibited eye movements suggesting mental tracking performed particularly well in the production task (Experiment 2). There was, however, no decrement in performance when participants were asked to fixate the point where the target disappeared. For motion duration estimations, eye movements seem to be only a by-product of mental tracking.

Adult↗

PubMedDate not supplied

Season of birth contributes to variation in university examination outcomes.

Epidemiological studies show that birth season influences a wide range of biological parameters such as growth, reproduction, mental illnesses, dyslexia, personality, and success in school. The present study is aimed at examining birth season's relationship to examination marks achieved at a university in a very large contemporary sample of male and female undergraduate students. We find that female university students born in spring and summer achieve better marks than those born in autumn and winter. Male students born in spring receive worse marks than those born in other seasons of the year. Furthermore, we find a birth-week periodicity in examination results of female students, with highest examination results for those born in May. We suppose that biological mechanisms might explain part of the observed effects.

Adult↗