At the heart of much of the research of the psychology of personality is an assumption called the “lexical hypothesis,” sometimes called the “lexical approach” and sometimes the “sedimentation hypothesis." There are two postulates one must accept to support the lexical hypothesis. First, those personality characteristics that are important to a group of people will eventually become a part of that group's language. Second, more important personality characteristics are more likely to be encoded into language as a single word. The lexical hypothesis was first proposed by the English psychologist Sir Francis Galton in the late 19th century and later used extensively in the 20th century by American and German psychologists, most particularly Gordon Allport. Although it has been critiqued by many, it is the foundation for much of the personality trait psychology research that has been done in the 20th century, particularly for the Big Five personality trait assessment.
Fundamentally, the language that is used in personality research is based on adjectives — the descriptor words in each language. When you describe a woman as “sweet” or “cunning” or a man as “amiable” or “devious,” you are making judgements about the person. The supporters of the lexical hypothesis argue that these are psycho-social judgements. Thus, personality research that is based on the lexical hypothesis makes extensive use of adjective lists. These adjectives are single words that are used a lot in everyday language, and we assume regular people know and understand what is meant when they are pronounced.
But despite its widespread use in the study of personality, the lexical hypothesis has been challenged. Here are just a few of the criticisms of the hypothesis.
- Using verbal descriptors in investigation of behavioral individual differences is methodologically flawed. Adjectives, or descriptors, were created by groups of people not to individuate personality types but to exchange information and forward and organize actions by the people in the group. Using descriptors to impute widely-accepted mental characteristics may be a convenient measuring tool, but some scientists believe it is not valid.
- The assumption that a single word conveys some kind of wide acceptability as to meaning may be exactly backward. Human personality traits are probably too complex for a single word, and it may be that whole paragraphs of description are needed to do it justice.
- Regular people use descriptors in ambiguous and vague ways. Asking them to describe the traits of other people’s personalities, therefore, may not be a good way of collecting scientific data.
- Personality-descriptive terms change over time and differ in meaning across dialects, languages, and cultures.
In this activity, you will be asked to get into a pair and exchange words from adjective lists that you believe describe an animal. You could do the same with a famous person or a person that the two of you both know. The purpose of the activity is to see if you experience some of the difficulties that the critics of the lexical hypothesis have suggested. The sources in this activity are here to help you do the activity: List of 50 animals from which you choose; list of positive adjectives; list of negative adjectives.