Young children use their hands to tell their mothers what to say

Children produce their first gestures before their first words, and their first gesture+word sentences before their first word+word sentences. These gestural accomplishments have been found not only to predate linguistic milestones, but also to predict them. Findings of this sort suggest that gesture itself might be playing a role in the language‐learning process. But what role does it play? Children's gestures could elicit from their mothers the kinds of words and sentences that the children need to hear in order to take their next linguistic step. We examined maternal responses to the gestures and speech that 10 children produced during the one‐word period. We found that all 10 mothers ‘translated’ their children's gestures into words, providing timely models for how one‐ and two‐word ideas can be expressed in English. Gesture thus offers a mechanism by which children can point out their thoughts to mothers, who then calibrate their speech to those thoughts, and potentially facilitate language‐learning.     

Somatic responses in behavioral inhibition

In the present study, skin conductance responses (SCRs) were measured postdecision and prefeedback in a go/no-go (GNG) task in which participants used response feedback to learn when to respond or not to respond to numeric stimuli. Like somatic markers in gambling tasks and somatic reactions to error monitoring in choice reaction time tasks, SCR patterns distinguished between correct and incorrect trials over time. These somatic reactions were disrupted by a reversal of GNG contingencies, and they were facilitated by pretraining of the stimulus—response mappings. In all cases, however, the somatic reactions appeared to be a product of competent decision making rather than a contributor to performance. Differential somatic responses to good and bad choices appear to be a robust and fairly general phenomenon, but researchers should be cautious in assuming that the somatic responses contribute to performance.     

Motion adaptation shifts apparent position without the motion aftereffect

Adaptation to motion can produce effects on both the perceived motion (the motion aftereffect) and the position (McGraw, Whitaker, Skillen, & Chung, 2002; Nishida & Johnston, 1999; Snowden, 1998; Whitaker, McGraw, & Pearson, 1999) of a subsequently viewed test stimulus. The position shift can be interpreted as a consequence of the motion aftereffect. For example, as the motion within a stationary aperture creates the impression that the aperture is shifted in position (De Valois & De Valois, 1991; Hayes, 2000; Ramachandran & Anstis, 1990), the motion aftereffect may generate a shift in perceived position of the test pattern simply because of the illusory motion it generates on the pattern. However, here we show a different aftereffect of motion adaptation that causes a shift in the apparent position of an object even when the object appears stationary and is located several degrees from the adapted region. This position aftereffect of motion reveals a new form of motion adaptation--one that does not result in a motion aftereffect--and suggests that motion and position signals are processed independently but then interact at a higher stage of processing.     

Measuring central executive functioning: what's in a reading span?

Although variations of Daneman and Carpenter's (1980) Reading Span Test (RST) have seen increasing use in both cognitive and neuropsychological research, the specific mental operations involved in performing it remain unclear. We tested 80 undergraduates to examine the extent to which speed of processing, manipulation capacity, and susceptibility to interference contributed to RST performance. The results suggest that, rather than unitary central executive or processing speed functions underlying RST performance, at least two factors, manipulation capacity and susceptibility to interference, underlie the task. Further study of RST operations may lead to a better understanding of the nature of the central executive itself.     

Inter-group alliance dynamics in Indo-Pacific bottlenose dolphins (Tursiops aduncus)

Animal Cognition - The social intelligence hypothesis holds that complex social relationships are the major selective force underlying the evolution of large brain size and intelligence. Complex...     

The cost of simplifying complex developmental phenomena: a new perspective on learning to walk

Researchers can study complex developmental phenomena with all the inherent noise and complexity or simplify behaviors to hone in on the essential aspects of a phenomenon. We used the development of walking as a model system to compare the costs and benefits of simplifying a complex, noisy behavior. Traditionally, researchers simplify infant walking by recording gait measures as infants take continuous, forward steps along straight paths. Here, we compared the traditional straight‐path task with spontaneous walking during 20 minutes of free play in 97 infants (10.75–19.99 months of age). We recorded infants’ footfalls on an instrumented floor to calculate gait measures in the straight‐path and free‐play tasks. In addition, we scored videos for other critical aspects of spontaneous walking—steps per bout, shape of walking path, and step direction. Studying infant walking during free play incurred no cost compared with the straight‐path task, but considerable benefits. Straight‐path gait was highly correlated with spontaneous gait and both sets of measures improved with walking age, validating use of the straight‐path task as an index of development. However, a large proportion of free‐play bouts were too short to permit standard gait measures, and most bouts were curved with omnidirectional steps. The high prevalence of these “non‐canonical” bouts was constant over development. We propose that a focus on spontaneous walking, the phenomenon we ostensibly wish to explain, yields important insights into the problems infants solve while learning to walk. Other areas of developmental research may also benefit from retaining the complexity of complex phenomena.     

Emotional expression and heart rate in high-risk infants during the face-to-face/still-face

In infants, eye constriction—the Duchenne marker—and mouth opening appear to index the intensity of both positive and negative facial expressions. We combined eye constriction and mouth opening that co-occurred with smiles and cry-faces (respectively, the prototypic expressions of infant joy and distress) to measure emotional expression intensity. Expression intensity and heart rate were measured throughout the face-to-face/still-face (FFSF) in a sample of infants with prenatal cocaine exposure who were at risk for developmental difficulties. Smiles declined and cry-faces increased in the still-face episode, but the distribution of eye constriction and mouth opening in smiles and cry-faces did not differ across episodes of the FFSF. As time elapsed in the still face episode potential indices of intensity increased, cry-faces were more likely to be accompanied by eye constriction and mouth opening. During cry-faces there were also moderately stable individual differences in the quantity of eye constriction and mouth opening. Infant heart rate was higher during cry-faces and lower during smiles, but did not vary with intensity of expression or by episode. In sum, infants express more intense negative affect as the still-face progresses, but do not show clear differences in expressive intensity between episodes of the FFSF.