Monthly Archives: December 2009

Ladder of Inference – Peter Senge

Although we like to think of ourselves as evolved thinkers, we have actually evolved to make decisions that shortcut most active thinking.

Consider our ancestors as they walked across the savannah, looking for their next meal, they too were being hunted.

The bushman that waited to consider if the moving shadow was actually a lion rather than a gazelle often became the lion’s next meal! It paid us to assume things and the bushman that believed all moving shadows ‘could’ be lions often survived b running away to hunt (and breed) another day. They also often missed out on a meal too!

So we, as a race, have selectively bred ourselves to make shortcuts in our decision making bast on our beliefs.

Beliefs therefore  are a significant factor in how we see the world. Our beliefs and values constrain our thinking so that we can make judgements more rapidly. The verb for this is ‘to prejudge’, and it is the root of the term prejudice. We make decisions with a much of the thinking already completed from our previous experience.

Having recently re-read Peter Senge’s ‘The Fifth Discipline’ I came across the Ladder of Inference.

This model describes the thinking process that we go through, often without realising it, to get from a fact to a decision or action.

Figure 1 shows the ‘thinking stages’ as rungs on a ladder.

Inference Ladder

Figure 1.  The Inference Ladder

The model highlights the thinking steps that can lead to jumping to the wrong conclusions.

Starting at the bottom of the ladder, we:

  • Observe things from reality and identify facts
  • From these observations we select specific data based on our beliefs and prior experience
  • Interpret what the data mean
  • Apply our existing assumptions (sometimes without even considering them)
  • Draw conclusions based on the interpreted facts and our assumptions
  • Develop beliefs based on these conclusions
  • Take actions that seem correct because they are based on what we believe

The value of this model is that it gives us a model that helps us recognize that our thinking process can be flawed and often brings us to conclusions that are often prejudged rather than carefully considered. We naturally skip reasoning steps. If we are aware of this thinking shortfall, we can force ourselves out of the habit and take a more objective, step by step reasoning process and so reach more effective decisions.

Dare to Aspire


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