Logo Utrecht University

UiL OTS Labs


Baby lab

In the babylab (room K.11) we run experiments to study language acquisition and language development of young infants. Current setup with three movable video screens, three animated lights and three speakers in a three-sided booth allows to run the head-turn preference procedure, the preferential looking procedure, the switch procedure and other experiments of similar nature.

For experiments involving interaction by the caregiver or experimenter with the infant the flex lab is better suited.

Technical specs

Test room

  • The test room houses a three-walled booth in which the infant and its caregiver are to be seated.
  • Sound dampened by open cell foam cushions placed on the walls.
  • The three-walled booth (with ceiling) consists of an aluminium box-shaped framework onto which unbleached cotton tent cloth is strapped on the inside, similar to construction used at Baby Lab Maastricht; internal dimensions: width 185 cm, depth 185 cm, height 197 cm; see drawing below
  • Lighting: dimmed, in booth (i.e. under the tent cloth) approx. 65 lux
  • Chair: regular comfortable four legged chair; positioned as depicted in drawing below


Left speaker position and normal position of left LED box for head turning experiments; instead of the LED box the left display monitor can be hung here
Right speaker position and normal position of right LED box for head turning experiments; instead of the LED box the right display monitor can be hung here
Normal position of left display monitor for preferential looking experiments
Normal position of right display monitor for preferential looking experiments
Camera position, frontal speaker position and normal position of frontal display monitor can be hung here for switch procedure experiments

All equipment (camera, speakers, monitors) are behind the canvas spanning the framework. The camera peeks though a hole in the canvas. The monitors can be made visible as needed to the infant by removing the canvas insets normally covering the LED boxes and monitors. The height from floor to center of LED boxes and display monitors is 95 cm.

The camera records in a mirrored manner. This means that when you present a stimuli on the left side it’s also on the left side of the recording.

Internal equipment

  • Headphones Echelon Telex (aviation headset); to be worn by caregiver to prevent the caregiver from hearing stimuli presented to the baby and to give instructions to the caregiver if necessary
  • Color video camera JVC TK-C1481EG
  • 3x 15″ monitor Benq GW2406z (IPS-VA technology.)
  • 3x speaker Tannoy X in 20x20x12 cm in custom made boxes.

See above drawing for the positions of camera, monitors, and speakers.

External equipment

  • Recording computer
    • Kubuntu 16.04
    • Recording Software: Open Broadcaster Studio
    • Default HP Elitedesk 800 G2 MT
    • Special card: BlackMagic Decklink video capture card
  • Stimulus-presentation computer (Custom build system to incorporate all the required peripherals)
    • Operating system: Kubuntu 16.04
    • OS installed on an SSD, user data on an HDD
    • Graphical card: 3x NVIDIA NVS 310 (vBlank timing not in sync.)
    • High accuracy response box: BeexyBox B
    • Soundcard: Asus Xonar (CMI8788)
    • Processor: Intel(R) Core(TM) i5-7400 CPU @ 3.00GHz
    • RAM size: 8 GB
  • Headphones Beyerdynamic DT250/80
  • Logitech C920 Webcam
  • Microphone Sennheiser ME-64
  • Microphone preamplifier/mixer Advantadge SPM413e
  • Headphones amplifier Symmetrix 506E
  • Mono amplifier Marantz MA6100 (drives frontal speaker)
  • Stereo amplifier Rotel RB-850 (drives left and right speakers)

Script Settings Configuration


Because there are multiple monitors the configuration for which window opens at which monitor is not arbitrary and different per Zep version. Head 0 is always the researcher display.

Zep 1.x

Monitor Position Zep-1.x-head Number
Front/Center 3
Left 1
Right 2

Zep 2.x

Monitor Position Zep-2.x-head Number
Front/Center 3
Left 2
Right 4

Sound-Channels Setting Configuration

The soundcard has multiple channels. The sound device needs to be opened with at least 4 channels. The following table shows which channels correspond to which channel number and to which speaker position:

Speaker-Box Position Channel Channel Number Note
Front/Center Front Left 0
Front Right 1 Front right is not connected
Left Rear Left 3
Right Rear Right 4

Room details

Usage rules

Keeping the facilities in this lab in the best possible condition requires your cooperation; please read the house rules and stick to them. Especially important:

  • Never ever change or remove any wiring; don’t pull out any plugs
  • No eating or drinking (except coffee, tea, water)
  • Clean up
  • Ask for help, report all problems