Overwriting of phonemic features in serial recall

We tested two explanations of the phonological similarity effect in verbal short-term memory: The confusion hypothesis assumes that serial positions of similar items are confused. The overwriting hypothesis states that similar items share feature representations, which are overwritten. Participants memorised a phonologically dissimilar list of CVC-trigrams (Experiment 1) or words (Experiment 2 and 3) for serial recall. In the retention interval they read aloud other items. The material of the distractor task jointly overlapped one item of the memory list. The recall of this item was impaired, and the effect was not based on intrusions from the distractor task alone. The results provide evidence for feature overwriting as one potential mechanism contributing to the phonological similarity effect.     

The universal SNARC effect: the association between number magnitude and space is amodal

It is thought that number magnitude is represented in an abstract and amodal way on a left-to-right oriented mental number line. Major evidence for this idea has been provided by the SNARC effect (Dehaene, Bossini, & Giraux, 1993): responses to relatively larger numbers are faster for the right hand, those to smaller numbers for the left hand, even when number magnitude is irrelevant. The SNARC effect has been used to index automatic access to a central semantic and amodal magnitude representation. However, this assumption of modality independence has never been tested and it remains uncertain if the SNARC effect exists in other modalities in a similar way as in the visual modality. We have examined this question by systematically varying modality/notation (auditory number word, visual Arabic numeral, visual number word, visual dice pattern) in a within-participant design. The SNARC effect was found consistently for all modality/notation conditions, including auditory presentation. The size of the SNARC effect in the auditory condition did not differ from the SNARC effect in any visual condition. We conclude that the SNARC effect is indeed a general index of a central semantic and amodal number magnitude representation.     

FACSGen 2.0 animation software: generating three-dimensional FACS-valid facial expressions for emotion research

In this article, we present FACSGen 2.0, new animation software for creating static and dynamic three-dimensional facial expressions on the basis of the Facial Action Coding System (FACS). FACSGen permits total control over the action units (AUs), which can be animated at all levels of intensity and applied alone or in combination to an infinite number of faces. In two studies, we tested the validity of the software for the AU appearance defined in the FACS manual and the conveyed emotionality of FACSGen expressions. In Experiment 1, four FACS-certified coders evaluated the complete set of 35 single AUs and 54 AU combinations for AU presence or absence, appearance quality, intensity, and asymmetry. In Experiment 2, lay participants performed a recognition task on emotional expressions created with FACSGen software and rated the similarity of expressions displayed by human and FACSGen faces. Results showed good to excellent classification levels for all AUs by the four FACS coders, suggesting that the AUs are valid exemplars of FACS specifications. Lay participants' recognition rates for nine emotions were high, and comparisons of human and FACSGen expressions were very similar. The findings demonstrate the effectiveness of the software in producing reliable and emotionally valid expressions, and suggest its application in numerous scientific areas, including perception, emotion, and clinical and neuroscience research.     

Acoustic variability and individual distinctiveness in the vocal repertoire of red-capped mangabeys (Cercocebus torquatus)

Acoustic variability and individual distinctiveness of vocal signals are expected to vary with both their communicative function and the need for individual recognition during social interactions. So far, few attempts have been made to comparatively study these features across the different call types within a species' vocal repertoire. We collected recordings of the six most common call types from 14 red-capped mangabeys (Cercocebus torquatus) to assess intra- and interindividual acoustic variability, using a range of temporal and frequency parameters. Acoustic variability was highest in contact and threat calls, intermediate in food calls, and lowest in loud and alarm calls. Individual distinctiveness was high in contact, threat, loud and alarm calls, and low in food calls. In sum, calls mediating intragroup social interactions were structurally most variable and individually most distinctive, highlighting the key role that social factors must have played in the evolution of the vocal repertoire in this species. We discuss these findings in light of existing hypotheses of acoustic variability in primate vocal behavior.     

Mood-congruent and mood-incongruent learning

We report two experiments that investigate the effect of an induced mood on the incidental learning of emotionally toned words. Subjects were put in a happy or sad mood by means of a suggestion technique and rated the emotional valence of a list of words. Later on, they were asked to recall the words in a neutral mood. For words with a strong emotional valence, mood-congruent learning was observed: strongly unpleasant words were recalled better by sad subjects and strongly pleasant words were recalled better by happy subjects. The reverse was true for slightly toned words: here, mood-incongruent learning was observed. Both effects are predicted by a two component processing model that specifies the effect of the mood on the cognitive processes during learning. Further evidence for the model is given by rating times measured in Experiment 2.     

Optical magnification as event information

Summary The geometrical optics of approach events is delineated. It is shown that optical magnification provides information about distance and time until collision. An experiment is described in which two objects - white styropor® spheres 10 cm in diameter, seen against a white plaster wall - were moved simultaneously at equal, constant speed along straight, converging paths at eye level towards a human observer and towards a common, virtual point of collision which either coincided with the observer's station point or was placed in front of, or behind, that point. Approach events differed with regard to trajectories, distances, velocities, and times-to-collision involved. Events were observed monocularly fixating and binocularly non-fixating, without head movements. The objects always stopped before colliding, and subjects had to respond to the virtual collisions. Most responses were too early, especially for impending collisions at, or behind the observers' station point. Responses for impending collisions in front of the observers tended to be too late, especially for larger total amounts of optical magnification and higher velocities, which together imply shorter times-to-collision. Relative errors were comparatively larger for very short and very long times-to-collision throughout, where events of the first kind were overshot, the latter ones undershot. Results are interpreted with reference to biological theories and the constraints imposed by geometrical optics. Special attention is focused on the issue of unavoidable, necessary confounding of variables in time-to-collision studies.     

Coincidence of attention deficit disorder and atopic disorders in children: Empirical findings and hypothetical background

ADDH children are often reported to display signs of allergies to various substances and/or atopic (AT) symptoms (i.e., atopic eczema, hay fever, or asthma). Since, at least for a subgroup of these children, a common biological background for both ADD and atopy may be assumed that may involve brain catecholamines, our hypothesis was that in a group of AT children (mainly atopic eczema) signs of ADD should appear more often than in controls. Parental hyperactivity ratings revealed a significantly higher frequency of ADD symptoms in the AT group, and laboratory tests sensitive to attentional capacity and inhibitory functions showed poorer performance in the AT children, the findings being similar to those reported in hyperactives. Thus, our results add support to the assumption of a common predisposing factor for both AT and ADDH in a subgroup of children.