Stretches

complex, but quite stereotyped movements carried out slowly with a clear sequence of body parts Head backward, trunk arching, and arms lifting. During pregnancy, they occur infrequently in the human fetes (see figure below).   Fetal stretches Appearing for the first the first time 10-15 weeks of gestation, they occur infrequently from 10 to 19 …

Stress (or adrenal) hormones

The hormones, typically corticosteroids, which are involved during the stress response. The hormones of the adrenal cortex respond to internal physiological stress, while those of the adrenal medulla are released in response to stress situations outside the body.  See Adrenal cortex, Adrenal gland, Adrenal medulla, Cortisol, Epinephrine (or adrenaline), Hormones, Hypothalamic-pituitary-adrenal (HPA) axis, Methylation, Nerve …

Strange situation test

A test developed and standardised by Mary D. Salter Ainsworth in which a stranger approaches an infant with and without the caregiver being present together with two brief separations, and various aspects of the infant‚was behaviour are measured. Three classes of attachment patterns were originally identified by Ainsworth based on the behavior of 10-24 month-old …

Stopping

A phonological pattern of substituting a stop consonant for another type of sound, especially fricative consonants as in ‘tick’ for ‘sick’.  See Cluster reduction, Final consonant reduction, Phonological process, Phonology

Stimulus orienting

A form of attention in which sensory organs and perceptual systems are aligned to increase responsively to environmental events.  This type of attention is present at birth and is fully developed very early in infancy.  See Attention, Overt attention

Stimulus enhancement

An object may become the focus of attention by virtue of the fact that someone else uses it. Such attention may lead the observer to increased manipulation of it, which in turn leads to the chance production of behaviours. Studies of imitation often attempt to distinguish stimulus enhancement from imitation . See Attention, Imitation

Stimulus-driven development

Also referred to as sensory-driven development, the termrefers to neural development of the brain on the basis of stimulation it isexposed to.  As a result ofstimulus-driven development, infants, for example, develop neural memory tracesfor their native language phonemes.  Incontrast, the lack of specific stimulation retards the cortical regions thatwould otherwise process such stimuli, such as …