Final answer:
Infants experience the expansion of short-term and long-term memory as they encounter and interact with their environment. Short-term memory can be susceptible to decay and interference, while long-term memory requires consolidation through processes such as rehearsal. Developmental milestones such as achieving object permanence showcase significant cognitive growth in infants.
Step-by-step explanation:
Throughout infancy, both short-term and long-term memory undergo significant changes. Short-term memory, which typically has a duration of 15 to 30 seconds, can be affected by factors such as memory trace decay and proactive interference.
Studies by Peterson and Peterson (1959) on trigrams demonstrated a marked decrease in retention over just a span of seconds. This indicates that without rehearsal or further processing, items in short-term memory may quickly fade.
In contrast, long-term memory, which is believed to have an unlimited capacity, requires the consolidation of memories at both the synaptic level and within the memory system, processes which can take hours or weeks, respectively.
In infancy, cognitive milestones like the development of object permanence at around 8 months indicate important growth in memory and understanding. The progression from sensory memory, through short-term memory, and into long-term memory follows a model originally proposed by Atkinson and Shiffrin (1968).
Memory consolidation is aided by processes such as active rehearsal and elaborative rehearsal, helping information move from short-term to long-term memory. During the sensorimotor stage of cognitive development, infants discover the world and develop their cognitive abilities as they interact with it.
As infants grow, they gain better control over their memories, indicating significant cognitive growth during this stage.