Which age group typically does not yield reliable behavioral test results?

The age group under 6 months typically does not yield reliable behavioral test results due to several developmental factors. Infants in this age range are still in the early stages of auditory and cognitive development, making it challenging to obtain consistent and valid responses during behavioral testing. Their ability to respond to auditory stimuli is limited, as they may not yet exhibit the attention span or behavioral cues necessary for reliable assessments.

Additionally, testing methodologies designed for older children rely on certain responses, such as behavioral reactions or deliberate actions, which infants are not fully capable of executing. Their responses may be reflexive rather than indicative of conscious auditory perception, leading to difficulties in accurately assessing their hearing abilities.

In contrast, older age groups like those from 6 months to 1 year, 1-3 years, and 3-5 years have progressed developmentally to a point where more reliable behavioral responses can be observed, thus facilitating more accurate assessments of hearing.