“My students aren’t ready for PBL.”
In PBL workshops with teachers, I ask them to describe the skillsets of the Ideal Graduate from their school. I once had a high school teacher say, “I want my students to be able to write a complete sentence.”
Of course, we would be failing if students couldn’t complete basic skills, but the implication of comments like this, is that “You don’t know my students. They are so low ability that I could never do a PBL project without first teaching them a long list of basic skills first.” This is “pyramid” thinking and it is damaging to students by setting low expectations of them.
Misconceptions about Bloom’s Pyramid
It has been documented that Bloom did not invent the pyramid image so often associated with his taxonomy, nor does it accurately display his ideas.
Bloom’s Taxonomy has been revised and inverted, but I am still not sure that the majority of educators get the point. Bloom’s Taxonomy was never meant to be hierarchal or sequential. In other words, one does not HAVE to remember and understand basic knowledge BEFORE they can analyze or create.
Upon reading that Maslow’s Hierarchy of Needs has both a similar pyramid and misconceptions. I learned about a better analogy: the humble ladder. Daniel Wren argues that Maslow’s Hierarchy could best be understood as multiple rungs on a ladder that are being used at the same time. Bloom’s Taxonomy works the same way.
Bloom’s Taxonomy should not be viewed as steps to be completed in sequence as knowledge and skills are mastered like leveling up in a video game. Instead think of each student on a ladder with their feet on one rung and their hands holding another as they lean their body against the other rungs. Students are constantly moving up and down Bloom’s Ladder as needed in the moment.
Bloom’s Ladder and PBL
PBL offers a great methodology for the proper use of the ladder analogy. A project is launched with an entry event which exposes students to a challenging problem. The driving question asks students to analyze and evaluate the problem and then create a solution. So PBL starts by getting students excited about the top rungs of the ladder.
Next comes the Need to Know process where students ask questions about what they don’t know to be successful. Basically students are identifying what bottom rungs of the ladder are missing in order for them to make it to the top.
Throughout the middle of a project students move up and down the ladder, evaluating and analyzing the problem and researching their own questions to fill in what they need to remember and understand.
Every project ends with students demonstrating their learning. Oftentimes they create a physical object such as an art piece or model. Other times they write a plan or essay analyzing the problem and presenting solutions. Whatever the final artifact of their learning looks like, it provides evidence of students at the top rungs of the ladder.
Get on the Ladder!
Here’s the kicker, what is the purpose of a ladder? It is a tool to get to an area out of reach, oftentimes to do important work. So if we think of the higher rungs of Bloom’s Taxonomy as where we want students functioning the majority of the time, then the ladder analogy works. One does not grab a ladder unless they have a desire to reach a higher place for a purpose.
The problem with many students in traditional schools is that they aren’t interested in getting on the ladder. The teacher never shows a goal at the top of the ladder that is meaningful to the majority of students. They have no motivation to even step onto the rungs of remember and understand because they have no idea where the steps could lead to.
PBL launches by showing students what is waiting at the top of the ladder. It starts with engagement, motivation, and a purpose for the learning so that students are eager to grab onto the ladder, moving up and down, developing skills as needed until they reach their goal of a creative solution at the top.
So don’t limit students to the bottom rungs of Bloom’s Taxonomy. The upper rungs provide the context and motivation for the knowledge acquisition on the lower rungs. Use PBL as a structure to guide students to the top of Bloom’s Ladder!