Head-Turn Preference Procedure

Purpose of this ZEP-based experiment is to see whether an infant participant
can detect a difference between two types of auditory stimuli. The
infant sits on the caregiver lap facing a wall on which a green
light, an invisible speaker and a camera is mounted. On each side
wall a red light (or other visual stimuli) and an invisible speaker are mounted.
In this implementation there is a familiarization phase and a test phase.

For each trial in the test phase the infant’s attention is drawn to
one the side lights (blinking). When the infant looks at the blinking
light a sequence of sound stimuli starts and a timer runs as long
as the infant keeps looking at the blinking light. The trial ends
when the infant looks away too long (or when a particular number of
stimuli have been presented). In the familiarization phase that
precedes the test phase a similar contingency procedure is used but
only for the lights; the sound stimuli once started continue until
all have been presented.

Please refer to the README.md for details!