Table 1.

Predictions derived from causal model theories and respective research for systems of causal beliefs in general and beliefs about depression in particular.

Assumptions of causal model theories	Predictions for systems of causal beliefs	Predictions with respect to lay theories of depression
Causal reasoning is triggered by unexpected, abnormal events (Hilton and Slugoski, 1986; Kahneman and Miller, 1986).	Causal beliefs concern abnormal conditions more often than normal events or conditions.	Depression is a frequent, but abnormal condition. Therefore, people across different cultural groups should hold causal beliefs about depression.
Causal beliefs represent directed, generic causal relations among cause and effect variables (Waldmann, 1996).	Causal relations are not only represented on the token level as relations among particular instances, but also as causal laws, i.e., generic causal relations, on a type level.	People across different cultural groups should have assumptions about causal factors that generally lead to depression.
Beliefs about individual causal relations are integrated into more complex causal models (Waldmann, 1996; Sloman, 2005).	Causal beliefs about a particular issue should form complex causal models.	People across different cultural groups should have interrelated beliefs about the causes, symptoms and consequences of depression.
Mechanisms are represented by mechanism placeholders, which represent merely the presence of an interconnecting mechanism (Pearl, 2000; Glymour, 2001).	Causal mechanisms are assumed to be present or absent. Knowledge about causal mechanisms is vague, often no details are known.	People across different cultural groups should have better knowledge about causal factors relevant for depression than knowledge about the underlying causal mechanisms.
Higher-order theories are necessary to induce causal models for a particular issue (Tenenbaum et al., 2011).	Causal models for specific issues conform to higher-order theories.	People across different cultural groups should possess higher-order theories, which inform models of depression. Causal beliefs about depression should align with these higher-order theories.
Higher-order theories are underdetermined by observable evidence (Kemp et al., 2010). Causal models of a particular issue have to directly conform to observations.	Many different higher order theories might be held and applied to a particular issue.	Higher order theories may deviate between different cultural groups. Higher order theories informing causal models should deviate more strongly than causal models of depression.
	Causal models should align whenever observations are similar.
Observed causal relations in the world are the basis for the induction of causal beliefs. Inferred causal relations are as simple as possible to account for the observations made (Lagnado and Sloman, 2002; Fernbach and Sloman, 2009). Hypotheses involving hidden causes are generally underdetermined by the observed data (Kemp et al., 2010).	Causal relations involving directly observable variables are easier to learn than causal models involving hidden variables that need to be inferred.	Causal models with respect to directly observable causes and effects should be similar in different cultural groups given that the environments in which they live are similar.
	Hidden causes are only inferred when observations require to do so.	As observable causes do not fully account for depression, people across different cultural groups should have assumptions about hidden factors that contribute to depression.
	There is less agreement on hidden than observable causes.	People from different cultural groups should agree more on observable causes than hidden causes of depression.
Assumptions concerning the usage of causal beliefs	Predictions	Predictions with respect to depression
Categorization is based on beliefs about the causal structure underlying a category (Rehder and Hastie, 2001).	Depending on assumptions about the underlying causal structure, the same instances may be categorized differently.	Depending on assumptions about the causes of depressive symptoms and depression as an illness, the same patient may be diagnosed as medically ill or not. Patients should be more likely to be diagnosed as ill when they present with symptoms that are causes of other symptoms (e.g., depressive thinking style) or symptoms that are caused by many other symptoms (e.g., high level of distress).
Diagnosis is based on assumptions about causal structure underlying an illness (Kim and Ahn, 2002).
Judgments are based on causal knowledge when respective knowledge is available (Garcia-Retamero and Hoffrage, 2006; Krynski and Tenenbaum, 2007; Kahneman, 2011).	Causal beliefs may bias judgments when probabilistic instead of causal judgments are requested; causal knowledge may support probabilistic judgments by giving meaning to probabilistic information and allowing decision makers to integrate the information into a causal model representation.	Causal beliefs may contribute to the over-diagnosis of depression, when the typical symptoms and causal factors are present, despite a low base rate in the respective groups of patients.
		Causal beliefs may also lead to an under-diagnosis of depression, when depressive symptoms are explained away as normal reactions to transient conditions or specific events.
Decisions on actions are based on causal or instrumental knowledge (Hagmayer and Sloman, 2009; Hagmayer and Meder, 2013).	Decision makers use causal knowledge to infer the consequences of novel options. Choices are based on the predicted causal consequences.	Persons across different cultural groups should take their beliefs about the causes of depression into account, when rating and/or choosing a treatment for depression. Therefore, preferences should agree with causal beliefs.