Certainty in Religious Belief Scale

Abstract

The Certainty in Religious Belief Scale (CRBS), developed by Robert H. Thouless in 1935, is a classic instrument designed to measure the subjective degree of conviction or certainty that an individual holds regarding various statements. Unlike typical attitude scales that measure agreement or disagreement with a proposition, the CRBS specifically focuses on the intensity of the belief state, ranging from absolute certainty of truth to absolute certainty of falsity. The scale is notable for including a diverse range of 40 propositions, mixing specific religious tenets (e.g., the existence of God, biblical literalism) with statements concerning general knowledge, social issues, and even verifiable facts, allowing researchers to study whether certainty is a generalized trait or domain-specific.

This instrument was pioneering in the field of the psychology of religion by separating the cognitive dimension of belief (the content) from the affective dimension of conviction (the intensity). The scale’s inclusion of non-religious statements serves as a control mechanism to assess a generalized tendency towards high or low certainty across diverse domains.

Keywords

Religious psychology, certainty, religious belief, conviction, psychometrics, attitude measurement, R. H. Thouless, 1935, subjective conviction.

Authors

Robert Henry Thouless.

Purpose

The primary purpose of the CRBS was to investigate the psychological phenomenon of conviction, particularly as it relates to religious statements. Thouless sought to determine if individuals display a general tendency toward high or low certainty across different domains, or if the level of certainty is strictly dependent on the specific content of the statement being evaluated. This research was foundational in the study of how subjective conviction operates independently of the truth value or objective evidence for a proposition.

By including statements of varying types—religious, political, scientific, and factual—the scale allows for the calculation of a score reflecting the subject’s overall tendency toward certainty, providing insight into the relationship between belief content and the psychological feeling of knowing. The instrument was explicitly designed to measure the dimension of intensity rather than merely the direction of the attitude.

Construct

The core construct measured is the degree of subjective certainty. In the context of the CRBS, certainty is operationalized as the individual’s level of confidence in the truth or falsity of a given statement. This construct is distinct from simple agreement (i.e., whether one believes the statement is true) because it captures the intensity and psychological firmness of that belief. The instrument posits that certainty is a measurable dimension of attitude strength.

Thouless’s work suggested that certainty might function as a measurable psychological trait, a tendency (or ‘set’) that influences how an individual processes information and expresses conviction across various domains, not just those related to religious belief. The scale is therefore often used to study cognitive styles related to dogmatism and rigidity of thought.

Validity

Formal psychometric validation studies common today were nascent in 1935. However, the scale possesses strong Content Validity given that the items directly sample a broad range of religious tenets prevalent during the era, alongside control items spanning factual and philosophical domains. Thouless’s original paper established the scale’s ability to differentiate individuals based on their overall tendency toward certainty.

Subsequent research utilizing the CRBS often employed Construct Validity assessments by correlating certainty scores with measures of dogmatism, rigidity, and general attitude strength, demonstrating that high certainty correlates positively with more rigid cognitive styles, regardless of the direction of the belief itself. The inclusion of neutral items allows for a measure of generalized certainty that can be correlated with other personality variables.

Reliability

Specific internal consistency estimates (e.g., Cronbach’s Alpha) for the original 1935 administration are not explicitly detailed in the source material. However, later administrations of the CRBS, particularly those compiled in large compendiums of measures, generally found acceptable levels of Test-Retest Reliability for the generalized certainty score, suggesting that the tendency toward conviction is a relatively stable characteristic over time.

The breadth of the 40 items, covering theological, scientific, and socio-political statements, helps ensure the scale provides a robust measure of the overarching certainty construct, mitigating the impact of single item ambiguities on the overall score and contributing to adequate internal consistency across the item pool.

Factor Analysis

While the original 1935 study focused primarily on calculating a composite certainty score (the average score assigned to all statements), later exploratory factor analyses of similar instruments derived from Thouless’s work often suggest a multidimensional structure. It is hypothesized that the 40 items typically load onto several factors, distinguishing between core religious beliefs (e.g., existence of God, divinity of Christ), specific historical or mythological religious claims (e.g., Jonah and the fish), and general non-religious factual knowledge.

The scale’s complexity, incorporating theological, scientific, and political statements, means that a simple unidimensional factor structure measuring only ‘religious certainty‘ is unlikely. Researchers typically analyze religious certainty scores separately from scores derived from the non-religious control items to isolate the domain-specific nature of conviction.

Instrument

Test Type: Self-report Psychological Scale.

Format: 40 statements rated on a 7-point bipolar certainty scale, ranging from complete certainty that the statement is true to complete certainty that the statement is false, with a midpoint of complete uncertainty.

Language Available: English (Original).

Population Group: General population, primarily utilized with university students and adults in psychological studies of religion.

Age Group: Adolescents and Adults (Typically 16+).

Population Details: Originally standardized on British university students in the 1930s as part of R. H. Thouless’s research into the psychology of religious belief.

Test Methodology: Respondents indicate their degree of certainty regarding the truth or falsity of each statement using the 7-point continuum. Scoring involves assigning numerical weights (e.g., 7 for complete certainty of truth, 1 for complete certainty of falsity, and 4 for complete uncertainty) and summing or averaging these values. The total score reflects the individual’s overall tendency toward certainty, regardless of the statement’s content.

Keywords

R. H. Thouless, 1935, religious attitudes, conviction intensity, philosophy of religion, psychological measurement, attitude strength.

Authors

Author ORCID Identifier: N/A (Pre-digital era instrument).

Affiliation Email addresses: N/A (R. H. Thouless was historically affiliated with the Department of Psychology, University of Cambridge).

Correspondence Address: N/A (Information not available for this historical measure).

Permissions & Fee and Test Year

The scale was published in 1935 and is generally considered to be in the public domain for non-commercial academic research use due to its age and widespread inclusion in historical measures compendiums. No specific fee or permission structure is typically required for its use.

Test Year: 1935.

Reference’s

Thouless, R. H. (1935). The tendency to certainty in religious belief. British Journal of Psychology, 26, 16-31.

Robinson, John P., & Shaver, Phillip R. (1969). Measures of Political Attitudes. Institute for Social Research, University of Michigan. Ann Arbor, Michigan.

The original PDF of this instrument can be downloaded here: http://psychclassics.yorku.ca/Thouless/certainty.pdf

Additional sources discussing this instrument include: Measures of Religiosity & Measures of social psychological attitudes.

Items of the Certainty in Religious Belief Scale

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

1. There is a personal God.
2. Jesus Christ was God the Son.
3. There are spiritual realities of some kind.
4. The world was created by God.
5. There is a personal Devil.
6. Matter is the sole reality.
7. There is a God who is all-powerful.
8. There is a God who is altogether good.
9. There are such spiritual beings as angels.
10. Jonah was swallowed by a great fish and afterwards emerged a live.
11. Man has been evolved from lower forms of life.
12. There is an impersonal God.
13. Evil is a reality.
14. The spirits of human beings continue to exist after the death of their bodies.
15. Religion is the opium of the people.
16. There is no God (personal or impersonal).
17. The universe is expanding.
18. Attendance at church is a better way of spending Sunday than taking a walk in the country.
19. Moses was the author of the first five books of the Bible.
20. Christianity is a better Religion than Buddhism.
21. The Bible is literally true in all its parts.
22. Man is, in some degree, responsible for his actions.
23. There is a Hell in which the wicked will be everlastingly punished.
24. The spirits of persons who have died can sometimes communicate with the living.
25. Right will triumph.
26. Belief in evolution is compatible with belief in a Creator.
27. Hardship strengthens character.
28. Mary, Queen of Scots, was beheaded between 1580 and 1590.
29. Everything is relative.
30. Tigers are found in parts of China.
31. Hornets live in nests under the ground.
32. Sex is Evil.
33. Light travels to us from the sun in less than one minute.
34. Bacon was the author of the plays attributed to Shakespeare.
35. Green is a primary colour.
36. Sunlight is good for human health.
37. Members of the leisured class are supported by the ‘surplus value’ created by the workers.
38. Tariffs improve trade.
39. India has, on the whole, benefited from British rule.
40. The total national debt of Great Britain is more than a thousand million pounds.

The response options provided for each item are:

• I am completely certain that this statement is true.
• I am almost certain that this statement is true.
• I think that this statement is true, but I am not at all certain.
• I am completely uncertain about this statement.
• I think this statement is false, but I am not at all certain.
• I am almost certain that this statement is false.
• I am completely certain that this statement is false.