Novice vs. Expert learners
When students are tasked with solving novel problems they tend to miss deeper structures that experts notice while over-emphasizing surface details. This has led some within the Abstract Reductive Teaching with Cognition (ARTC) philosophy to present worked examples of algorithms for students to replicate. Students repeat these problems with minimal thinking in an effort to overlearn. These jumps are justified using cognitive load theory which says that our short-term memories can be overwhelmed by too many things at once.
The issues with the above approach will be deconstructed in a future post, but I want to start by pointing out how this has been accompanied by a major flaw in teaching. The sequence of vocabulary is critical in how students learn science. Let’s start by taking some chemistry definitions. These are the first definitions that came up on Google for these chemistry terms. Note how many abstract terms, tier II vocabulary terms, and tier 3 terms reside in those three definitions.
Resonance - resonance, also called mesomerism, is a way of describing bonding in certain molecules or ions by the combination of several contributing structures (or forms, also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.
Enthalpy - a thermodynamic quantity equivalent to the total heat content of a system. It is equal to the internal energy of the system plus the product of pressure and volume.
Molecule - a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
Think of all of the various incomplete models that a student may bring for a single term. Let’s define a model to be an underlying abstract concept that ties together multiple representations of said concept. When an expert proposes a defintion, they have a clear purpose behind how they are defining each term within a definition. A novice learner has limited ability to assign the appropriate representation. Within resonance, how many different interpretations will a student have for bonding. Will they link the relevance of “molecules or ions” back to the bonding term or will they substitute another meaning? Will they recognize that ion is referring to polyatomic ions rather than monatomic ions? The definition is useless to a novice student. At best what they can do is they can form an abstract association between the phrase and the term. At worst is they can link an inappropriate representation and further a misconception.
Fortunately there is an alternative called concept first, vocab last. In this instructional method, the students are provided with a phenomenon. Said phenomenon may include data, discrepant events, and qualitative observables. Immediately the student has concrete information providing a better connection to prior knowledge in LTM. This increases the odds of appropriate chunking when the student develops a mental model of the phenomenon. The teacher can then guide the students into a task where they develop a model. For a chemistry experiment, representations including graphs, data tables, equations/slope, particle models, and macroscopic observations are commonly used. When a definition is constructed at the end of this lesson the student has concrete evidence to set their basis for the terms within the definition. They have a shared common experience to draw from. And instead of being an abstract phrase associated with an abstract term, the vocabulary term serves as a retrieval cue for the concept or model that was demonstrated by the phenomenon. At this point the model can be extended to a new phenomenon. This allows the student to test their understanding of the concept by determining if the model is useful, applicable, or requires revision.
During this process the teacher can limit mathematical applications, particle models, vocabulary, or conceptual components at any given time. This focus means that cognitive overload is not at risk. Note how this process pulls the students’ prior knowledge into focus by utilizing that knowledge to construct meaning of the phenomenon, the underlying concept, and finally the vocabulary term as a means of communication about the concept. This approach to learning opens up possibilities for the teacher to vary the emotional engagement with the learning. A student might engage due to competitiveness, curiosity, obedience, spite, etc. But by varying the phenomenon the teacher can engage with more personal connection to students’ lives.
Sample progression using "density" model.
How would a student define density after each point in the sequence?
Figure 1: Whiteboard of student measurements of mass vs. volume of a series of blocks
made of a single material.
Figure 2: Students deploy density model to compare mass and volume relationships at
the particle level
Figure 3: Review poster where student connects representations of “density”
Figure 4: Discrepant event testing the new model of density: Will it float?
Video of wooden blocks with and without holes:
