Behavioural Laterality Battery
Background
The Behavioural Laterality Battery (BLB) is a standardized, free online test battery published in 2020 by Adam J. Parker and colleagues to measure cerebral lateralization and hemispheric dominance of emotion, language and motor processing outside of a controlled laboratory environment. Specifically, the BLB was developed to test large sample sizes via web platforms while maintaining high test-retest reliability. Results supported that at least three of their tested tasks (dichoticlistening, chimeric faces and finger tapping) showed considerable promise for online evaluation of cerebral lateralization. The resulting battery is publicly accessible and hosted on the Gorilla platform: BLB.
The BLB consists of 10 subtasks of which three (dichoticlistening, chimeric faces and finger tapping) are the main experimental lateralization tasks. The remaining tasks assess demographic information, self-reported handedness or run headphone and sound checks. The Millisecond BLB implementation allows researchers to run the complete battery or only use specific tests. All tests are described in more detail below.
Subtest 1: Demographic Survey
A basic demographics questionnaire to obtain participants' age, gender, education, self-assessed hand/foot preferences and whether they consider themselves as bilingual.
Subtest 2: Edinburgh Handedness Inventory
A self-report handedness assessment survey based on the Edinburgh Handedness Inventory by Oldfield from 1971. The survey asks participants to rate their preferred hand on a 5-point Likert scale for 10 activities such as writing, drawing, brushing teeth or using a broom. A 'Laterality Quotient (LQ)' (Range: -100 (left-hand preference) <= LQ <= 100 (right-hand preference)) is calculated based on the reported responses.
Subtest 3: Lexical Test for Advanced Learners of English (LexTALE)
LexTALE is a lexical decision task. It is intended for cognitive researchers studying participants with an advanced level of English as a second language. Parker et al used the test to screen participants for an advanced level of English proficiency.
The test presents 63 test items (3 practice items, 40 English words, 20 English-sounding nonwords) one-by-one in the middle of the screen, and participants must decide if the item is a true English word (then press 'yes') or not (press 'no'). The test does not impose any time constraints. A progress bar is always visible at the bottom of the screen.
The test reports an accuracy score that is calculated as non-weighted average of the percent correct performance on the 40 English words and the percent correct performance on the 20 nonwords.
Subtest 4: Miles Test of Ocular Dominance
The Miles Test is a simple and quick self-measure to determine eye dominance (left or right) in central gaze. Walter Richard Miles introduced the test in 1929 to objectively measure eye preference without the participant's conscious bias or hand preference interfering with the results.
The basic procedure asks a participant to hold both arms straight out in front and bring both hands together, overlapping fingers and thumbs to create a small triangular opening or hole. With both eyes open, participants are asked to look through the hole and focus on a small, distant object across the room. Then they are asked to close their left eye. If the object stays in the center, the right eye is declared to be the dominant one. If the object 'disappears', the left eye is the dominant one.
Subtest 5: Porta Test of Ocular Dominance
Like the Miles Test, the Porta Test is a quick behavioral test used to determine eye dominance. It relies on alignment to see which eye your brain prefers for visual input. It was first described by Italian physician Giambattista della Porta in 1593.
The basic procedure asks participants to pick a target such as a small object across the room and point with the index finger of an extended arm at it while keeping both eyes open. Then participants are instructed to close their left eye. If the object 'jumps', the right eye is determined to be the dominant eye. If the object stays in place, the left eye is the dominant eye.
Subtest 6: Headphone Check
The Headphone Check Procedure by Woods et al (2017) is intended as a screening check to ensure that participants are wearing headphones. The test is designed to be easy to pass when wearing headphones but it is difficult to pass when only the default loudspeakers of a device are used due to phase-cancellation. The test is included in the BLB because headphone usage is essential for the Dichotic Listening task.
After a short sound calibration to ensure that participants hear the sounds comfortably, participants work on 6 trials that present a soundfile playing three sounds sequentially. For each trial, participants must decide if the first, second, or third sound was 'the quietest' and press the corresponding response button. The task reports a binary (pass/fail) summary score.
Subtest 7: Stereo Check
This is a second simple headphone screening task. Participants hear a sound played into one ear only and then report the ear it was presented to. This ensures that headphones are used to run the Dichotic Listening task.
The task runs 6 trials with three left and three right-ear sounds, presented in random order. Participants are asked to play the soundfiles and must select a 'left' or 'right' response button. Like the Headphone Check, a single binary (pass/fail) summary score is reported.
Subtest 8: Chimeric Face Test
The Chimeric Face Test (CFT) is a behavioral task used to assess hemispheric asymmetry (lateralization) in (visual) emotional processing by presenting split faces. Participants are shown composite images—half-emotional/half-neutral—and must select the "emotional" face, generally revealing a right-hemisphere dominance for emotion by preferring left-side emotional expressions.
The test stimuli set designed by Michael Burt and colleagues (1997) consists of 16 stimuli: Each of four emotions (anger, disgust, happiness, sadness) is paired with the others (including itself for control items), so that each emotion is presented left four times. Participants work through two repetitions of this set for a total of 32 trials. The order of the stimuli is determined randomly. A short practice block with two different emotions (surprise, fear) precedes the test block.
The test compares (correctly) left selected emotions to (correctly) right selected emotions. The resulting 'Lateralization Ratio' is the main measure of overall emotion lateralization. The resulting scores fall between -1 and 1. Negative scores indicate a right-side advantage (left-hemisphere dominance for emotion), positive scores indicate the opposite (left-side advantage -> right-hemisphere dominance for emotion).
Subtest 9: Dichotic Listening Task
The BLB Dichotic Listening Task assesses the lateralization of language processing. It is a basic dichotic listing procedure that presents participants with different syllables such as 'ta' and 'da' simultaneously played in their right and left ear. Participants must then choose the syllable they heard best.
Participants are first introduced to the six syllables (da,ba,ga,ta,ka,pa) used in the task. Each syllable can be replayed as often as needed. Once they have been familiarized with the stimuli, they start a practice session that runs 9 trials. During all trials the stimuli are played into the left and right ear simultaneously. Six of the practice trials play the same syllables (e.g. da-da) into both ears and three trials play different ones (da-ba, ga-ta, ka-pa). The order of the practice trials is randomly determined. Participants listen to the syllables and have to decide which syllables they heard (best), by selecting one of six response buttons, one for each syllable. No feedback is provided. The four test blocks run all 36 syllable combinations in random order.
The task reports a 'Lateralization Index', a ratio that compares the number of correct responses when a left sound was selected to those when the right sound was selected. The resulting scores fall between -1 and 1. Negative scores indicate a right-ear advantage (left-hemisphere dominance for language processing), positive scores indicate the opposite (left-ear advantage -> right-hemisphere dominance for language processing).
Subtest 10: Finger Tapping Task
The BLB Fingertapping Task assesses manual preference. In this task, participants tap out a sequence of keyboard keys (right index finger: TUMB; left index finger: WRVX) as many times as possible within 30 seconds. This was repeated four times for each hand. There is no practice session.
The task computes a 'left hand' and a 'right hand' score based on the number of correct taps for the respective hands. The final 'Lateralization Score' sets the difference of these two scores relative to their sum. The resulting scores fall between -1 and 1. Negative scores indicate a right-hand advantage (left-hemisphere dominance for motor skills), positive scores indicate the opposite (left-hand advantage -> right-hemisphere dominance for motor skills).
What it Measures
The Behavioural Laterality Battery (BLB) measures cerebral lateralization and hemispheric dominance of emotion, language and motor processing
Psychological domains
- Brain Lateralization: The principle that specific cognitive functions are dominant in either the left or right hemisphere of the brain
- Emotion Lateralization: Hemispheric asymmetry in emotion processing
- Language Lateralization: Hemispheric asymmetry in language processing
- Motor Lateralization: Hemispheric asymmetry in motor skills
Main Performance Metrics
- Lateralization Scores: The Lateralization Scores for the core BLB tasks are set up in such a way that negative scores show a right side/ear/hand advantage (left hemisphere dominance) and positive scores show the opposite.
Psychiatric Conditions
The BLB is intended for online academic research with non-clinical populations.
An online battery developed by Parker et al (2020) for assesing hemispheric specialization and behavioural laterality.
References
Search Google Scholar for peer-reviewed, published research using the Inquisit Behavioural Laterality Battery.
Adam J. Parker , Zoe V. J. Woodhead , Paul A. Thompson & Dorothy V. M. Bishop (2020): Assessing the reliability of an online behavioural laterality battery: A pre-registered study, Laterality, DOI: 10.1080/1357650X.2020.1859526 https://doi.org/10.1080/1357650X.2020.1859526