Current research finds that young adults can hold between items in short-term (working) memory if they do not use any type of retention strategy.

The number that is most often cited for the short-term memory is 7; this is also known as the "magical number 7". 

However, the more recent research suggests that the number is actually 3,4 or 5 - shorter than 7, and this also holds for young adults (this are the results of studies from the year 2001 onward, while 7 is an older finding).