Trait aggression was measured with the
Aggression Questionnaire.
Perceived trustworthiness of peers was measured with a modified version of the
Trust Scale44, which is designed to measure the perceived trustworthiness of other people.
The
Prosocial Behaviors Scale45 was used to measure individual variability in prosocial behaviors and attributes (e.g., “I try to help others,” “I spend time with those friends who feel lonely”).
The
Empathy Quotient46 was used to measure the ability to detect, and sensitivity to respond to the feelings of others (e.g., “I really enjoy caring for other people,” “I am good at predicting what someone will do”). The 22 items were scored on a 7-point scale (from
strongly disagree to
strongly agree [overall
α = .80]).
Personality characteristics were measured with the
Ten-Item Personality Inventory.
The items measure the “Big 5” dimensions of personality (extraversion, agreeableness, conscientiousness, emotional stability, and openness to experiences) on a 7-point scale (from
disagree strongly to
agree strongly [overall
α = .71]).
Moral reasoning was measured with the
Moral Foundations Questionnaire48. The scale measures the reliance on, and endorsement of five psychological foundations of morality based on moral foundations theory. Each of the two parts of the scale contained four questions related to each foundation: (1) harm/care, (2) fairness/reciprocity (including issues of rights), (3) ingroup loyalty, (4) authority/respect, and (5) purity/sanctity. The items are scored on a 5-point scale (from
not at all relevant to
extremely relevant [part 1] and from
strongly disagree to
strongly agree [part 2] [overall
α = .79]).
Finally, visual facial threat perceptions were measured using facial stimuli created with FaceGen software
49. Six ambiguous facial stimuli were created by simultaneously setting the facial expression parameters of the software to the maximum levels for two discrete emotions, for every combination of emotions, from a total of four distinct emotions: sadness, joy, fear, and anger. Under each sketch, participants were instructed to identify the facial expression as displaying either:
anger (A)
, joy (J)
, fear (F)
, or
sadness (S). Participants’ threat perception responses were coded according to whether the reported emotion facilitates the affiliative (joy or sadness coded 0) or avoidant (anger or fear coded 1) dimensions of human emotionality
3. Latency since last cannabis consumption was measured on a 9-point scale from “within the past few hours” to “over a year ago”.