From social expectations to social cognition in early infancy.

The end of the first year marks an important social-cognitive transition for human infants. Around this time, they start to engage in a new variety of joint attentional behaviors not clearly present in the preceding months. These new social behaviors are thought to index infants' understanding of intentions in others-an understanding that ultimately gives way to an active participation in human culture. Given the importance of such understanding, the question is from where infants' new social-cognitive repertoire may originate. Well before the emergence of joint attention, infants are sophisticated social beings, readily able to form expectations about others and inclined to relate differentially to them. The author focuses on the potential connection between social expectations developing in the context of early face-to-face interactions and the social-cognitive changes taking place by the end of the first year of life.

Emerging sensitivity to the timing and structure of protoconversation in early infancy.

Thirty-six 2-, 4-, and 6-month-old infants were videotaped while interacting with a female adult stranger engaging in either organized or disorganized 1-min peekaboo games. Two-month-old infants gazed and smiled equally at the stranger, regardless of the relative organization of the peekaboo game. In contrast, 4- and 6-month-old infants smiled significantly more and gazed significantly less in the organized peekaboo condition than in the disorganized peekaboo condition. These results suggest that from a diffuse sensitivity to the presence of a social partner, infants by 4 months develop a new sensitivity to the narrative envelope of protoconversation, in particular the timing and the structure of social exchanges scaffolded by adults. These observations are interpreted as evidence of developing social expectations in the first 6 months of life. This early development is viewed as announcing and preparing the communicative competence that blossoms by the end of the 1st year.

Evaluation of resistance form for prepared teeth.

Resistance form of preparations for which castings were made in a large dental laboratory was evaluated. Each preparation was also evaluated for the placement of grooves. Evaluation of resistance form was done by grasping the casting between thumb and index finger and attempting to roll the uncemented casting off the die with finger pressure. Each preparation was tested for resistance form in all directions (buccal, lingual, mesial, and distal), from a fixed point of rotation. Evaluation was by tooth groups: incisors, canines, premolar, and molars. The preparations were found to have resistance form in 96% of the incisors, 92% of the canines, 81% of the premolars and only 46% of the molars. Only nine of 294 preparations evaluated had grooves. Mesial or distal grooves provided resistance to buccal and lingual dislodgment, and buccal or lingual grooves provided resistance to mesial and distal dislodgment.

A simplified palatal expansion prosthesis.

A palatal expansion prosthesis made of cast silver can be easily fabricated at any facility that has the ability to cast type III gold. The ductility and malleability of pure silver allow for ease of adaptation or alteration as a chairside or operating room procedure.