Co-morbidity of crying and feeding problems with sleeping problems in infancy: Concurrent and predictive associations

The co-morbidity of crying, feeding and sleeping problems at 5 months of age was investigated in a representative sample of 432 infants in South Germany. A crying, sleeping or feeding problem was reported in 32.7% of these infants by their parents and a further 14.6% had two or more of these problems. Little co-morbidity between crying and feeding problems was found. There were moderate to strong associations between crying and sleeping behaviours. Feeding problems showed little relationship to sleeping behaviour, but feeding type and frequency of feeds were related to night waking. Breastfed infants woke much more often at night. Crying and feeding problems at 5 months were poor predictors of sleeping behaviour at 20 or 56 months of age. Later sleeping behaviour was best predicted by infant sleeping behaviour. At 56 months, maternal distress due to sleeping and co-sleeping practices was predicted by maternal distress due to crying and feeding practices at 5 months of age. The predictions were significant but generally weak to modest in strength. Future studies on the consequences of crying or feeding problems should take into account patterns of co-morbidity. So-called ‘post-colicky’ sleep problems are not due to increased crying per se but rather appear to be the consequence of associated infant sleeping problems and parental caretaking patterns for dealing with night waking in infancy.     

Eye-hand coordination: oculomotor control in rapid aimed limb movements

Three experiments are reported in which Ss produced rapid wrist rotations to a target while the position of their eyes was being monitored. In Experiment 1, Ss spontaneously executed a saccadic eye movement to the target around the same time as the wrist began to move. Experiment 2 revealed that wrist-rotation accuracy suffered if Ss were not allowed to move their eyes to the target, even when visual feedback about the moving wrist was unavailable. In Experiment 3, wrist rotations were equally accurate when Ss produced either a saccadic or a smooth-pursuit eye movement to the target. However, differences were observed in the initial-impulse and error-correction phases of the wrist rotations, depending on the type of eye movement involved. The results suggest that aimed limb movements use information from the oculomotor system about both the static position of the eyes and the dynamic characteristics of eye movements. Furthermore, the information that governs the initial impulse is different from that which guides final error corrections.     

Cholinergic modulation of tonic immobility in the rabbit (Oryctolagus cuniculus).

The present study was performed to determine the effects of the anticholinergic agent scopolamine and the cholinergic agent physostigmine on tonic immobility in rabbits. Recordings of the electroencephalographic (EEG) activity from cortex and hippocampus were also made before, during, and after each test session. Scopolamine significantly prolonged the response and produced large amplitude slow wave activity in the EEG of both cortex and hippocampus. Physostigmine significantly shortened the duration of immobility and increased rhythmic slow activity in the frequency range of 5.5-9.1 Hz in the hippocampus while producing a desynchronized cortical rhythm. It is suggested that the cortex and hippocampus play a role in modulating tonic immobility duration by inhibiting the brain-stem structures thought to control this response.     

Suppression of precocial copulation by progesterone implants in the male chick forebrain.

Precocial copulation in 2-wk.-old male chicks, described behaviorally as free mount, tread, posterior contact, waggle, peek, and seize, was developed through hand-training experience and androgen treatment. Crystalline progesterone was then implanted in various forebrain or midbrain regions. Results indicated that progesterone inhibited copulatory behavior when placed in the periventricular areas of the preoptic-hypothalamic continuum. Progesterone implants in the preoptic lateral forebrain bundle regions also suppressed precocial copulation. Forebrain implants of cholesterol did not result in copulatory inhibition. The suppression of copulatory behavior was not accompanied by loss of weight or deficits in general activity or comb growth. These data indicate that brain regions responsible for progesterone-induced copulatory inhibition are similar in neuroanatomical distribution to those involved in testosterone-induced copulatory activation.     

Visual masking,mental age,and retardation

Performance of retarded subjects under both forward and backward masking was less accurate than either an equivalent chronological age or equivalent mental age group of normals. It was suggested that the iconic memory impairment of retarded subjects in attributable in part to mental retardation and not simply to low mental age.     

A Bayesian procedure for separately estimating storage and retrieval components of forgetting

A Bayesian procedure was developed to estimate separately the probability of sufficient storage, θ_s, and the probability of successful retrieval, θ_τ, on an individual subject basis. The method involves a probabilistic analysis of the subject's performance on a task that randomly intermixes recall with recognition trials. Two experiments using the Brown-Peterson paradigm were performed to demonstrate and validate the estimation procedure. The experiments showed that both θ_s and θ_τ decrease as a function of increasing retention interval. The results of both experiments suggest the necessity of a two-factor theory for short-term memory.     

Shape constancy and a perceptual bias towards symmetry

In attempting to judge whether a briefly presented rotated figure was symmetrical (circle or square) or asymmetrical (ellipse or rectangle), a bias towards perceiving symmetry was evident. This bias appears to be perceptual rather than judgmental in origin in that it was affected neither by variations in the probability of occurrence of symmetrical figures nor by familiarization with the stimuli. A characterization of the stimulus similarity space based on the shape-slant invariance hypothesis is presented, and a model which incorporates both the similarity space and the symmetry bias is proposed. The model can account for our paradoxical finding that the more asymmetrical some projected images, the more likely they will be perceived as symmetrical. This model can also account for Massaro’s (1973, 1975) results on shape constancy. However, Massaro’s theory was not supported in that extension in depth did not account for increased difficulty of shape judgments.