Mirjam Ebersbach

Are juvenile domestic pigs (Sus scrofa domestica) sensitive to the attentive states of humans?--The impact of impulsivity on choice behaviour.

Previous studies have shown that apes, dogs and horses seem to be able to attribute attentive states to humans. Subjects had to choose between two persons: one who was able to see the animal and one who was not. Using a similar paradigm, we tested a species that does not rely strongly on visual cues, the domestic pig (Sus scrofa domestica). Subjects could choose between two unfamiliar persons, with only one showing attention, in three different conditions (body, head away, body turned - head front). Subjects (n=16) only showed a tendency towards the attentive human in the head away condition. However, by pooling those two conditions where the position of the human head was the only salient cue, we found a significant preference for the attentive person. Moreover, two approach styles could be distinguished - an impulsive style with short response times and a non-impulsive style where response times were relatively long. With the second approach style, pigs chose the attentive person significantly more often than expected by chance level, which was not the case when subjects chose impulsively. These first results suggest that pigs are able to use head cues to discriminate between different attentive states of humans.

Mental rotation and the motor system: embodiment head over heels.

We examined whether body parts attached to abstract stimuli automatically force embodiment in a mental rotation task. In Experiment 1, standard cube combinations reflecting a human pose were added with (1) body parts on anatomically possible locations, (2) body parts on anatomically impossible locations, (3) colored end cubes, and (4) simple end cubes. Participants (N=30) had to decide whether two simultaneously presented stimuli, rotated in the picture plane, were identical or not. They were fastest and made less errors in the possible-body condition, but were slowest and least accurate in the impossible-body condition. A second experiment (N=32) replicated the results and ruled out that the poor performance in the impossible-body condition was due to the specific stimulus material. The findings of both experiments suggest that body parts automatically trigger embodiment, even when it is counterproductive and dramatically impairs performance, as in the impossible-body condition. It can furthermore be concluded that body parts cannot be used flexibly for spatial orientation in mental rotation tasks, compared to colored end cubes. Thus, embodiment appears to be a strong and inflexible mechanism that may, under certain conditions, even impede performance.

Comparing apples and pears in studies on magnitude estimations

The present article is concerned with studies on magnitude estimations that strived to uncover the underlying mental representation(s) of magnitudes. We point out a number of methodological differences and shortcomings that make it difficult drawing general conclusions. To solve this problem, we propose a taxonomy by which those studies could be classified, taking into account central methodological aspects of magnitude estimation tasks. Finally, we suggest perspectives for future research on magnitude estimations, which might abandon the hunt for the mathematical model that explains estimations best and turn, instead, to investigate the underlying principles of estimations (e.g., strategies) and ways of their improvement.

Evidence for a Spatial–Numerical Association in Kindergartners Using a Number Line Task

In Western cultures, small numbers are often associated with the left and large with the right space. We investigated whether this association is already present in kindergartners and second graders. Children (N = 59) estimated the position of numbers on a number line that was labeled either with a small number on the left side and a large number on the right side (i.e., left-to-right orientation) or vice versa (i.e., right-to-left orientation). The estimations were less accurate if the number line was oriented from right to left and if the children started with this condition. The results suggest that already kindergartners possess a culture-typical spatial–numerical association that develops before the acquisition of reading and writing skills and significantly affects the accuracy of numerical estimations. The performance of second graders, too, was affected by the orientation of the number line, but to a smaller degree than that of kindergartners.

Achieving a New Dimension: Children Integrate Three Stimulus Dimensions in Volume Estimations.

Although J. Piaget (1968) assumed that children up to 7 years old are unable to consider more than 1 stimulus dimension in their judgments, subsequent research has demonstrated that preschoolers can consider 2 dimensions, such as the width and length of rectangles to estimate their area (F. Wilkening, 1979). The present study addressed the question of whether children can also take 3 stimulus dimensions into account. Kindergartners, 1st and 3rd graders, and adults (N = 73) estimated the volume of cuboids that required the consideration of 3 dimensions: width, height, and length. The results showed that the majority of kindergartners already based their volume estimations on all 3 dimensions. A considerable proportion of kindergartners even integrated width, height, and length multiplicatively. There was no dramatic improvement with age, implying the implicit understanding of volume to develop relatively early in childhood. The results are discussed in light of childrens cognitive competencies concerning multidimensional reasoning.

Symbolic versus non-symbolic magnitude estimations among children and adults.

The ability of children and adults to generate symbolic and non-symbolic magnitude estimations was examined in the light of their familiarity with numbers. Children (6-year-old kindergartners, 7-year-old first graders, and 9-year-old third graders) and adults made symbolic estimations either by saying number words that matched numbers of dots (i.e., perception task) or by generating numbers of dots that matched given number words (i.e., production task). In the non-symbolic estimation task, participants generated the corresponding numbers of dots they had seen previously (i.e., reproduction task). In line with the bidirectional mapping hypothesis, children and adults made underestimations in the perception task, overestimations in the production task, and intermediate estimations in the reproduction task. However, the performance of kindergartners and first graders showed significant deviations from the predictions of the bidirectional mapping hypothesis. Their performance in the production task lagged significantly behind that in the perception task, implying that these tasks are not mirrored processes among young children. In addition, they made systematic overestimations in the non-symbolic reproduction task, suggesting that biased mapping occurs here as well. The results are discussed with regard to childrens familiarity with numbers and potential estimation strategies.

On the relationship between children's perspective taking in complex scenes and their spatial drawing ability.

Depicting space and volume in drawings is challenging for young children in particular. It has been assumed that several cognitive skills may contribute to childrens drawing. In the present study, we investigated the relationship between perspective-taking skills in complex scenes and the spatial characteristics in drawings of 5- to 9-year-olds (N= 121). Perspective taking was assessed by two tasks: (a) a visual task similar to the three-mountains task, in which the children had to select a three-dimensional model that showed the view on a scene from particular perspective and (b) a spatial construction task, in which children had to plastically reconstruct a three-dimensional scene as it would appear from a new point of view. In the drawing task, the children were asked to depict a three-dimensional scene exactly as it looked like from their own point of view. Several spatial features in the drawings were coded. The results suggested that childrens spatial drawing and their perspective-taking skills were related. The axes system and the spatial relations between objects in the drawings in particular were predicted, beyond age, by certain measures of the two perspective-taking tasks. The results are discussed in the light of particular demands that might underlay both perspective taking and spatial drawing.

The Role of Cognitive Flexibility in the Spatial Representation of Children's Drawings

Representing the spatial appearance of objects and scenes in drawings is a difficult task for young children in particular. In the present study, the relationship between spatial drawing and cognitive flexibility was investigated. Seven- to 11-year-olds (N = 60) were asked to copy a three-dimensional model in a drawing. The use of depth cues as an indicator of spatial drawing was examined. Furthermore, cognitive flexibility was assessed by three measures: the Wisconsin Card-Sorting Test 64 (reactive flexibility), the Five-Point Test (spontaneous flexibility), and omission/inclusion (representational flexibility). The results revealed significant relationships between all measures of flexibility and the depth cues in childrens drawings. However, only spontaneous and representational flexibility turned out to be significant predictors of the spatial drawing score. The results are discussed in light of the specific requirements of spatial representations in drawings.

Semantic congruency and the (reversed) Colavita effect in children and adults.

When presented with auditory, visual, or bimodal audiovisual stimuli in a discrimination task, adults tend to ignore the auditory component in bimodal stimuli and respond to the visual component only (i.e., Colavita visual dominance effect). The same is true for older children, whereas young children are dominated by the auditory component of bimodal audiovisual stimuli. This suggests a change of sensory dominance during childhood. The aim of the current study was to investigate, in three experimental conditions, whether children and adults show sensory dominance when presented with complex semantic stimuli and whether this dominance can be modulated by stimulus characteristics such as semantic (in)congruency, frequency of bimodal trials, and color information. Semantic (in)congruency did not affect the magnitude of the auditory dominance effect in 6-year-olds or the visual dominance effect in adults, but it was a modulating factor of the visual dominance in 9-year-olds (Conditions 1 and 2). Furthermore, the absence of color information (Condition 3) did not affect auditory dominance in 6-year-olds and hardly affected visual dominance in adults, whereas the visual dominance in 9-year-olds disappeared. Our results suggest that (a) sensory dominance in children and adults is not restricted to simple lights and sounds, as used in previous research, but can be extended to semantically meaningful stimuli and that (b) sensory dominance is more robust in 6-year-olds and adults than in 9-year-olds, implying a transitional stage around this age.

The Relationship Between Children’s Familiarity with Numbers and Their Performance in Bounded and Unbounded Number Line Estimations

Children’s estimation skills on a bounded and unbounded number line task were assessed in the light of their familiarity with numbers. Kindergartners, first graders, and second graders (N = 120) estimated the position of numbers on a 1–100 number line, marked with either two reference points (i.e., 1 and 10: unbounded condition) or three reference points (i.e., 1, 10, 100: bounded condition). Estimations were more accurate and less variable in older compared to younger children and, beyond age, in children who were familiar with larger numbers. The number of reference points yielded neither a main effect nor an interaction effect with familiarity. Our results underline that children’s familiarity with numbers is a pivotal factor for the quality of number line estimations that might even obliterate potential effects of additional reference points.