|Questionnaires||Parameter||Positive β indicates more or better||Age of child|
Bayley mental scale |
Bayley motor scale 
Visual and auditory discernment, eye-hand coordination, imitation, language development, memory and problem solving capacity. Mean score for the general population of 100 (± SD 15).|
Motor development. Mean score for the general population of 100 (± SD 15).
|Infant Behaviour Questionnaire (IBQ) : Temperament as observed by the mother||
Scale 1 = stress and latency to approach sudden or novel stimuli|
Scale 2 = smiling and laughter
Scale 3 = distress to limitations
Scale 4 = activity level
Scale 5 = duration of orienting
Smiling or laughter from the child in general caretaking and play situations.
Persistence and goal oriented behaviour.
Gross motor activity: movement of arms and legs, squirming and locomotor activity.
Habituation: more attention to and/or interaction with a single object for extended periods of time.
|Milestones: developmental abilities||
1 = grasping|
2 = rolling over
3 = sitting up
4 = crawling
5 = first steps alone
Time needed to achieve the milestone:|
Grasping and picking up objects.
Learning to flip over from his back to his tummy and vice versa.
To sit up without support.
First steps alone unaided (first steps alone).
|Tests||Measurement type||Positive β indicates a higher capacity in terms of||Age of child|
|Reynell Language Developmental Scale (RTOS): receptive language development level measured by oral instructions to carry out small tasks while playing with toys .||Verbal comprehension scale||Receptive language development.||36 months|
|Snijders-Oomen non-verbal intelligence test (SON 2.5–7), : Intelligence: reasoning and visuospatial abilities||
Three intelligence quotients (IQ) can be calculated with this intelligence tests with a mean score for the general population of 100 (± SD 15)|
Total intelligence scale: SON-IQ
Performance Scale (PS) IQ
Reasoning Scale (RS) IQ
(Nonverbal) intelligence (IQ).|
Performance IQ: better in making puzzles, mosaics and patterns.
Reasoning IQ: better in categories, situations and analogies.
|Observation of toy preference: 7 min. Lasting observation of masculine/feminine play behaviour [25, 26]||
Masculine play behaviour|
Feminine play behaviour
Non-gender specific play behaviour
Time playing with masculine toys: little cars, fire truck, construction blocks, toy gun.|
Time playing with feminine toys: little dolls, hair doll, baby doll, kitchen accessories.
Time playing with non-gender specific toys: puzzle, book
The number of times the child switches between toys.
|NES 3 (Neurobehavioral Evaluation System) ||Continuous Performance Test||Computerised vigilance task adapted according to Patandin et al., .||36 months|