Seeking one’s heading through eye movements

A study of eye movements during simulated travel toward a grove of four stationary trees revealed that observers looked most at pairs of trees that converged or decelerated apart. Such pairs specify that one’s direction of travel, calledheading, is to the outside of the near member of the pair. Observers looked at these trees more than those that accelerated apart; such pairs do not offer trustworthy heading information. Observers also looked at gaps between trees less often when they converged or diverged apart, and heading can never be between such pairs. Heading responses were in accord with eye movements. In general, if observers responded accurately, they had looked at trees that converged or decelerated apart; if they were inaccurate, they had not. Results support the notion that observers seek out their heading through eye movements, saccading to and fixating on the most informative locations in the field of view.     

Behavioral and developmental consequences of early rearing experience for captive giant pandas (Ailuropoda melanoleuca)

Mother-reared (MR) and peer-reared (PR) captive giant panda (Ailuropoda melanoleuca) cubs were compared to evaluate the effects of early removal from mother on behavioral development. Males and females and twins and singletons were compared to assess the effects of social setting on behavioral development. Subjects included 2 PR females, 3 MR females, 3 MR males, and 3 mothers. MR cubs spent more time manipulating bamboo and fell more often than PR cubs. PR cubs spent more time inactive. Male cubs directed more playful behavior at their mothers. Twins spent more time play fighting with their mothers than with their siblings. The results suggest that peer-rearing does not provide young pandas with the same level of social stimulation as mother-rearing.     

Lexical input as related to children's vocabulary acquisition: effects of sophisticated exposure and support for meaning

A corpus of nearly 150,000 maternal word-tokens used by 53 low-income mothers in 263 mother-child conversations in 5 settings (e.g., play, mealtime, and book readings) was studied. Ninety-nine percent of maternal lexical input consisted of the 3,000 most frequent words. Children's vocabulary performance in kindergarten and later in 2nd grade related more to the occurrence of sophisticated lexical items than to quantity of lexical input overall. Density of sophisticated words heard and the density with which such words were embedded in helpful or instructive interactions, at age 5 at home, independently predicted over a third of the variance in children's vocabulary performance in both kindergarten and 2nd grade. These two variables, with controls for maternal education, child nonverbal IQ, and amount of child's talk produced during the interactive settings, at age 5, predicted 50% of the variance in children's 2nd-grade vocabulary.     

Fleeing or not: Responsivity of a chased target influences the cognitive representation of the chasing action

The chasing action, in which an actor chases a target, is a fundamental activity for the evolutionary shaping of social abilities. Where previous research has emphasized the chaser’s role, the current study explored whether the fleeing responsivity of a chased target influences the cognitive representation of the chasing action. We investigated this with a change-detection task, in which a set of chasing actions, either exhibiting or not exhibiting fleeing behavior, were memorized in sequence, and it was tested whether a memorized action reappeared after altering an object’s appearance. The results suggest that the target’s fleeing responsivity influenced the detection of representation-related changes in the appearance of the involved agents, especially when the appearance of one target was replaced with another (i.e., a new pair, but with the same functional role), showing impaired sensitivity to change for the chasing action (Experiment 1). This effect disappeared, however, when the perceived chasing from presented movements was impaired, while displaying largely the same low-level differences as those present in earlier trials through the use of mirrored chasing (Experiment 2) and setting the faced direction opposite of the moving direction (Experiment 3). These findings suggest that the fleeing responsivity of the chased target can influence the stored representation of the action. This differentiation may be attributed to the stronger construction of social interaction structure for chasing action with fleeing than without, since the fleeing behavior can be deemed a contingency cue for social interaction interpretation.