Apart from the most characteristic of baby sounds, the cry, a number of other sounds have been described by Peter Ostwald (1 963) during the first 24 hours of life. These include the burp, the vomit'sound, the gulp, the sneeze, the cough, the hiccup, the gurgle, squeaks, the lip-puckering sound, and flatulence. Within the first year this list can be elaborated to include the raspberry, laughter, banging, humming, lalling, and babbling. Although many of these non-linquistic sounds may serve a communicative function, this discussion will be restricted to the infant cry as a communicatory signal and how it relates to the child's later cognitive and emotional development.The framework of this discussion is that of attachment theory as most extensively elaborated by John Bowlby (1969) and Mary Ainsworth (1967). Crying is considered by these investigators to be an attachment behaviour along with other behaviours such as smiling and following in that these behaviours promote proximity to or contact with the caretaker, usually the mother.' Within an ethological framework, attachment behaviours are believed to have originally evolved in humans to perform a protective function by bringing the infant into close proximity with his mother who could then defend him against predators and other dangers. Although such close proximity between mother and infant is not necessary to ensure protection in our present society, Bowlby and Ainsworth argue that babies are nevertheless genetically programmed to cry when out of contact or distressed and that their behaviour is adapted to the prototype of a responsive mother. Especially before the infant is physically mobile, his only means of achieving proximity is through signalling behaviours such as crying and smiling. Crying is considered a distal cue since its effectiveness in stimulating caretaking behaviour does not depend on the relatively close proximity required for the effectiveness of more proximal cues such as smiling, facial expressions, and bodily gestures.
FUNCTIONS OF CRYlNGSince crying unlike smiling, is not a gratifying behaviour to adults, much controversy has been aroused in the past over its control and I . Paper presented at the Australian Conference on Cognitive Developnient. Canberra, February. 197s. 2. Apart from its use to describe the samples of the studies reviewed, the tern? "mother" is used throughout this paper for convenience and is nor intended to imply the biological mother but rather the in fant's primary caretaker whether the biological mother. father, or other mother-substitute.