Leveling and sharpening were first identified by Allport and Postman (1947), who coined the terms to describe systemic inaccuracies people exhibit when they recollect stories.4 By the mid-1950s, Gestalt psychologists George Klein and Philip Holzman had described leveling and sharpening as cognitive controls used in memory recollection and the processing of new information and stimuli. They created the Schematizing Test to categorise leveling and sharpening responses: through these test future scholars could measure how much people rely on past memories, and people’s ability to notice small distinctions when faced with a new set of stimuli .5
Fast forward to the 1990s, when psychologists began to gain interest in the consequences of leveling and sharpening on judgement and decision making. In his 1997 book Cognitive Styles and Classroom Learning, Harry Morgan argued that sharpeners are usually more accurate in their comparisons of new and old knowledge, allowing them to make more informed decisions. On the other hand, he wrote that levelers tend to combine parts of old memories together, causing them to have hazy memories with missing details and that they tend to oversimplify new material. As such, the thinking amongst psychologists in recent years is that a ‘sharper’ memory can lead to better decisions.6
Example 1 – How levelling and sharpening bolsters gender stereotypes.2
In 2001, Ganske and Hebl conducted a study that explored the influence of gender stereotypes on the recollection of a story. A group of students were told the same story about two individuals named John and Silvia. Some participants were told the story from John’s perspective, with all pronouns switched to the masculine, while the others heard the story narrated by Silvia, using feminine pronouns.
The results showed substantial leveling and sharpening in the participants’ recollections. Those who heard John’s story recalled how he “played violent video games”, “drank beer” and “became very aggressive”, but failed to acknowledge the times he cried, took long baths, or did some baking to help cope with his sadness. From Sylvia’s story, participants added details that weren’t mentioned in the original story at all, such as “she hugged her teddy bear”, and “she shopped all day”, while forgetting details like her competitiveness and her somewhat aggressive behavior towards Terry, another character in the story.
The study provides strong evidence for our use of leveling and sharpening to reinforce cognitive biases, particularly gender stereotypes.
Example 2 – Are you a leveler or a sharpener? The Schematizing Test.5
Several psychologists have investigated the different extents to which individuals engage in leveling and sharpening. Klein and Holzman developed the Schematizing Test (aka the Squares Test) in the 1950s to examine the way individuals manage incoming stimuli over time. In this test, participants watch a screen that shows a series of squares ranging in size from 1 to 14 inches. After each square is displayed, participants are given a few seconds to record whether they detected a change in size, and their estimate of the size of change. People who fail to notice small changes in size are considered ‘levellers’ while those who notice even the most discreet changes are deemed ‘sharpeners’. In other experiments, people who recall several memories from the past in an attempt to categorize newly acquired information are ‘levellers’. On the other hand, ‘sharpeners’ rely on fewer but more profound memories when interpreting information.6 As a result of experiments like this, experts in cognitive learning today believe that if we want to improve our decision-making, we should focus on sharpening to ensure the accuracy of our memories.