In a conversational system, the optimal system response
time, or in this case delay before the animated character’s
reply, is not necessarily the fastest possible time supportable by
the software. In the present study, children’s response latencies
averaged 4.7 seconds, and ranged between 1.6 and 10.1
seconds for all twenty-four participants. In addition, the
response latencies for the younger children averaged 6.2
seconds, which was significantly longer than 4.2 seconds in the
older group. During interpersonal conversation, similar
response latency durations have been observed in our lab. For
example, response latencies for 7-to-10-year-old children
engaged in a similar query-answer activity with an adult
averaged 3.9 seconds, and ranged from 2.5-5.6 seconds. In the
future, additional research will be needed to model what the
optimal human-computer response delays should be for new
conversational interfaces, in part depending on the user group
and conversational domain. In addition, future research needs
to develop adaptive conversational interfaces that can both: (1)
adjust to the substantial individual differences among users,
and (2) track and adapt to changes in key features of users’
spoken language during dynamic conversation. Such systems
then would be capable of supporting the mutual speech
adaptation that characterizes interpersonal conversation, which
could improve the synchrony and quality of the humancomputer
conversational exchange.