Direct measurement of cognitive load in multimedia learning

Brunken, R., Plass, J.L., & Leutner, D. (2003). Direct measurement of cognitive load in multimedia learning. Educational Psychologist, 38, 53-61.


Learner’s prior knowledge determines the level of cognitive load that individual experiences.
Paper describes more reliable and valid approach for measuring the cognitive load: dual-task approach.

Three types of cognitive load:
1-Intrinsic: caused by the structure and complexity of the material, depends on component interactivity (amount of informational units the learner has to keep in working memory to understand the information)
2-Extraneous: caused by the format the information is presented
3-Germane load: caused by learners’ efforts to process and comprehend the material

Instructional strategies to reduce extraneous load and induce germane load:
worked examples, goal-free activities, strategies of imaging
activities based on completion effect, modality effect, and redundancy effect

(Total cognitive load ) - (Processing capacity of visual and auditory WM) = free cognitive resources
- if approaches zero, it causes high cognitive load on the learner

Dual-coding assumption: verbal and pictorial material processed and mentally represented in separate but interconnected systems. ( from Paivio’s dual coding theory)

Dual-channel assumption: visual and auditory information are processed in different systems (from visuospatial and phonological subsystems in Baddeley’s working memory)
- Learner actively select visual and verbal information and integrate their representations with prior knowledge by building referential connections.

Modality effect: information given in both visual and auditory is better than when it is given only visually.

Measurement:
indirect subjective measures: posttreatment questionnaire
direct subjective measures: rating of the difficulty of the material
indirect objective measures: performance outcome measures, comparing two it more different variants of multimedia instructions
- analysis of behavioral patterns or physiological conditions and functions
e.g. learner’s time-on-task , eye tracking, heart rate, pupil dilation
direct objective measures: neuroimaging techniques to measure brain activation during task execution
- tasks as word memorization, sentence comprehension or visual rotations
dual-task-paradigm: (a direct objective measure)learner has to perform two tasks simultaneously and both tasks require same cognitive resources in verbal and visual working memory.
-a secondary task is added to a primary task:
-learner’s performance in the secondary task can be a measure for cognitive load.
Benefits:
1- both tasks are at the same time so the measure can be at the very point in time when the load is induced
2- there are different secondary tasks like perception, preprocessing or information integratio which make it possible to identify where the cognitive load is imposed
2- different design variants for the same learner makes it independent from the individual differences
Issues:
1- secondary task requires the same cognitive resource as primary task
2- measure for the secondary task has to be reliable and valid.
3- secondary task has to be simple
4- secondary task has to be able to consume free cognitive capacity
In the paper, the experience is done by comparing two dual task conditions, and the reaction times were faster for audiovisual primary tasks than the visual only primary task condition

Issues with dual task approach:
1- depends on the sensory modality, require the use of auditory secondary tasks
2- secondary task, even though it is very simple, it can still affect the learning outcomes of the primary effect
3- need to know the prior knowledge of the learner
4- split attention and modality effect can be caused by the different instructional designs as well as the differences in attentional processing.