Psych 4/23

Fisher (dopamine)

Aim: Investigate neural basis of romantic love and dopamine reward pathways. Procedure: 20 participants in love shown photos of partner vs. neutral acquaintance during fMRI. Type: Lab (fMRI). Sample: 20 college-age adults. Results: Viewing partner activated dopamine-rich reward areas (caudate nucleus, VTA) — romantic love is a motivational drive. Strengths: High internal validity; objective physiological measures. Limitations: Small unrepresentative sample; artificial lab setting. Category: Biological

Buss (1989)

Aim: Test evolutionary predictions about sex differences in mate preferences cross-culturally. Procedure: Questionnaires rating 18 mate characteristics across 37 cultures. Type: Survey. Sample: 10,047 participants across 6 continents. Results: Women valued resources/ambition more; men valued attractiveness/youth more — supports parental investment theory. Strengths: Huge cross-cultural sample; standardised questionnaire. Limitations: Social desirability bias; may not reflect actual mate choice. Category: Sociocultural

Buss (2001)

Aim: Investigate evolutionary sex differences in emotional vs. sexual jealousy. Procedure: Participants imagined partner being sexually vs. emotionally unfaithful; rated distress. Type: Survey. Sample: Large samples across multiple countries. Results: Men more distressed by sexual infidelity; women by emotional infidelity — consistent across cultures. Strengths: Cross-cultural replication; controlled hypothetical scenarios. Limitations: Hypothetical scenarios lack ecological validity; forced-choice format oversimplifies. Category: Biological

De Dreu (oxytocin)

Aim: Investigate whether oxytocin promotes prosocial behaviour specifically toward in-group members. Procedure: Double-blind RCT — male Dutch participants given intranasal oxytocin or placebo, then played economic games with in-group vs. out-group partners. Type: Lab experiment (RCT). Sample: ~280 male Dutch participants. Results: Oxytocin increased in-group cooperation but also out-group defensive aggression — "tend and defend" not universal prosociality. Strengths: RCT establishes causality; double-blind eliminates bias. Limitations: All-male Dutch sample; artificial economic game tasks. Category: Biological

Selfhout et al.

Aim: Test whether perceived vs. actual similarity predicts friendship quality over time. Procedure: Adolescents completed questionnaires at two time-points on music preferences, perceived similarity, and friendship quality. Type: Longitudinal survey. Sample: Dutch secondary school adolescents. Results: Perceived similarity predicted friendship quality more than actual similarity — supports Attraction Similarity Model. Strengths: Longitudinal design; distinguishes perceived vs. actual similarity. Limitations: Dutch adolescents only; music preference is a narrow measure. Category: Cognitive

Hazan & Shaver

Aim: Test whether Bowlby's attachment styles are reflected in adult romantic love. Procedure: 'Love quiz' published in newspaper — respondents chose attachment description and answered about relationships and childhood. Type: Survey (newspaper sample). Sample: 620 US adults (205 men, 415 women). Results: ~56% secure, ~25% anxious, ~19% avoidant. Attachment style linked to mental models formed in childhood. Strengths: First empirical link between childhood attachment and adult romance; large sample. Limitations: Self-selected biased sample; retrospective self-report subject to memory distortion. Category: Cognitive

Dion & Dion

Aim: Examine how individualist vs. collectivist cultural values influence romantic love. Procedure: Review of existing studies and new survey data comparing attitudes toward romantic love across cultures. Type: Cross-cultural survey/review. Sample: Cross-cultural comparative data across varied sample sizes. Results: Individualistic cultures base marriage more on romantic love; collectivist cultures prioritise practical factors. Strengths: Cross-cultural scope challenges Western-centric models; high ecological validity. Limitations: Individualism-collectivism is a broad variable; data is mostly correlational. Category: Sociocultural

Regan, Lakhanpal & Anguiano

Aim: Compare marital satisfaction and love in arranged vs. love marriages among South Asian Americans. Procedure: Questionnaires measuring passionate/companionate love, satisfaction, and commitment across marriage types. Type: Survey. Sample: 58 South Asian American adults (29 arranged, 29 love marriages). Results: No significant differences in love, satisfaction, or commitment between arranged and love marriages. Strengths: Controls for cultural background; challenges Western bias about arranged marriage. Limitations: Very small sample (n=58); convenience sample of South Asian Americans only. Category: Sociocultural

Gottman

Aim: Identify communication patterns that predict divorce. Procedure: Couples observed in 'Love Lab' during conflict discussion; facial expressions, physiology, and verbal interaction coded; followed up over 14+ years. Type: Longitudinal lab observation. Sample: Hundreds of couples followed over 14+ years. Results: The 'Four Horsemen' (criticism, contempt, defensiveness, stonewalling) predicted divorce with ~90% accuracy. Contempt was strongest predictor. Strengths: ~90% predictive validity; multimethod approach. Limitations: Lab may alter behaviour; mostly white middle-class US sample. Category: Cognitive

Bradbury & Fincham

Aim: Examine how couples' attributions for partner behaviour relate to marital satisfaction. Procedure: Married couples completed questionnaires measuring attributional styles and marital satisfaction at multiple time points. Type: Longitudinal survey. Sample: Married couples from community samples. Results: Distressed spouses made maladaptive attributions — blaming stable, global, intentional causes. Attribution style predicted future satisfaction. Strengths: Longitudinal design; validated standardised scales. Limitations: Self-report may not reflect actual cognition during conflict; causality is hard to establish. Category: Cognitive

Flora & Segrin

Aim: Examine how negative affect and communication patterns predict relationship satisfaction over time. Procedure: Couples completed questionnaires about communication, affect, and satisfaction at multiple time points. Type: Longitudinal survey. Sample: US couples from community settings. Results: Negative communication predicted decreases in satisfaction; positive communication buffered against dissatisfaction. Strengths: Longitudinal design; dyadic data from both partners. Limitations: Self-report subject to recall bias; attrition may bias toward stable couples. Category: Cognitive

Sherif — Robber's Cave

Aim: Investigate formation of inter-group prejudice and whether superordinate goals reduce conflict. Procedure: 22 boys at summer camp assigned to two groups — competition introduced, then superordinate goals requiring cooperation. Type: Field experiment. Sample: 22 white middle-class American boys aged ~11–12. Results: Competition produced rapid prejudice and hostility. Superordinate goals reduced conflict; simple contact alone was insufficient. Strengths: High ecological validity; strong experimental control. Limitations: Sample limited to white middle-class American boys; ethically problematic. Category: Sociocultural

Diab

Aim: Replicate Sherif's Robber's Cave findings in a different cultural context (Lebanon). Procedure: Lebanese boys at summer camp assigned to competing groups; superordinate goals attempted. Type: Field experiment. Sample: Lebanese boys aged ~11–12 from Beirut. Results: Hostility emerged more rapidly and intensely than in original. Experiment had to be stopped early — conflict became too severe to complete the superordinate goals phase. Strengths: Cross-cultural replication adds breadth; demonstrates robustness of inter-group conflict. Limitations: Experiment ended prematurely; ethically problematic — boys experienced genuine distress. Category: Sociocultural

Kerr (1983)

Aim: Investigate conditions under which social loafing occurs and whether it is motivational or due to coordination loss. Procedure: Participants performed tasks individually and in groups; identifiability of contribution was varied. Type: Lab experiment. Sample: Undergraduate students; lab convenience sample. Results: Social loafing reduced when contributions were identifiable — supports a motivational explanation over coordination loss. Strengths: High internal validity; isolates motivational explanation experimentally. Limitations: Lab tasks (rope pulling) lack ecological validity; undergraduate convenience sample. Category: Sociocultural

Clark & Clark

Aim: Examine racial identity and self-concept in Black American children using a doll preference task. Procedure: Black children aged 3–7 shown black and white dolls; asked about preference, identity, and positive/negative attributes. Type: Lab/quasi-experiment. Sample: 253 Black American children aged 3–7 from segregated and non-segregated US schools. Results: Majority of Black children preferred white doll and attributed positive qualities to it — used as evidence of psychological harm of segregation in Brown v. Board of Education. Strengths: Significant real-world impact on civil rights legislation; age-appropriate methodology. Limitations: Demand characteristics; doll preference may not reliably indicate internalised self-concept. Category: Sociocultural

Hart et al. / Phelps

Aim: Investigate whether the amygdala shows differential activation to own-race vs. other-race faces, reflecting implicit racial bias. Procedure: White and Black participants underwent fMRI viewing unfamiliar White and Black faces; amygdala activation recorded. Type: Lab (fMRI). Sample: White and Black participants in controlled fMRI study. Results: Both groups showed greater amygdala activation to other-race faces — own-race bias is reciprocal. Activation decreased with familiarity. Strengths: Objective neuroimaging evidence independent of self-report; own-race control condition. Limitations: Unfamiliar faces may reflect novelty not racial bias; small fMRI sample sizes. Category: Biological

Cook (1978)

Aim: Test conditions under which intergroup contact reduces prejudice, refining Allport's Contact Hypothesis. Procedure: White participants worked cooperatively with a Black confederate over several weeks under equal status, shared goals, and institutional support; prejudice measured before and after. Type: Lab/field experiment. Sample: White American adults in a workplace-simulation setting. Results: Contact under specified conditions (equal status, common goals, institutional support, acquaintance potential) significantly reduced prejudice. Simple contact without these conditions was ineffective. Strengths: Identifies specific conditions needed to reduce prejudice; longitudinal element increases validity. Limitations: Lab simulation may not generalise to real-world contact; only White participants' attitudes were assessed. Category: Sociocultural

Essock-Vitale & McGuire

Aim: Test Hamilton's kin selection theory — whether people preferentially help genetic relatives over non-relatives. Procedure: Women interviewed about who they gave and received help from during major life events; genetic relatedness of helpers calculated. Type: Survey/interview. Sample: 300 women from Los Angeles. Results: Helping was strongly skewed toward genetic relatives even after controlling for proximity and closeness — closer genetic relationship = more and greater help. Strengths: Real-life helping behaviour increases ecological validity; systematic coding of genetic relatedness. Limitations: Self-report subject to recall bias; difficult to disentangle kin selection from emotional closeness. Category: Biological

Toi & Batson

Aim: Test whether empathy produces genuinely altruistic motivation rather than disguised self-interest. Procedure: Participants heard a staged interview with a struggling student; empathy (high/low) and ease of escape from helping (high/low) were experimentally manipulated. Type: Lab experiment. Sample: Undergraduate students randomly assigned to conditions. Results: High-empathy participants helped regardless of ease of escape; low-empathy only helped when escape was difficult. Supports empathy-altruism hypothesis. Strengths: Manipulation of both empathy and escape cleanly tests altruistic vs. egoistic motivation; within-participant controls. Limitations: Demand characteristics — participants may have suspected the cover story; artificial helping task. Category: Cognitive

Levine et al.

Aim: Examine whether pace of life and economic productivity predict helping rates across countries. Procedure: Researchers staged helping scenarios (dropping papers, injured leg, blind person crossing) in cities across 23 countries; percentage of passers-by who helped was recorded. Type: Field experiment. Sample: Observations across 23 countries; thousands of naturally occurring helping opportunities. Results: Large cross-cultural differences — Rio de Janeiro and San José had highest rates; Singapore and New York had lowest. Helping negatively correlated with economic productivity and population density. Strengths: High ecological validity — natural behaviour in real settings; 23-country cross-cultural scope. Limitations: Observers not blinded to hypothesis — potential observer bias; cultural norms and safety concerns difficult to disentangle. Category: Sociocultural

Latané & Darley — Smoke-filled room

Aim: Investigate whether presence of others reduces likelihood of reporting an emergency. Procedure: Participants completed a questionnaire alone, with two naive participants, or with two passive confederates when smoke began filling the room. Type: Lab experiment. Sample: Male undergraduates at Columbia University. Results: 75% of lone participants reported smoke; 38% of three-person naive groups; only 10% with passive confederates. Demonstrates diffusion of responsibility and pluralistic ignorance. Strengths: High internal validity; established foundational bystander effect mechanisms. Limitations: Deception exposed participants to perceived fire hazard; all-male undergraduate sample. Category: Cognitive

Latané & Darley — Intercom seizure

Aim: Test whether perceived group size reduces likelihood of helping in an emergency. Procedure: Participants communicated via intercom when a confederate appeared to have a seizure; believed they were with 1, 2, or 5 others. Type: Lab experiment. Sample: Undergraduate students at Columbia University. Results: 85% helped when alone with victim; only 31% when 5 others believed present. Perceived group size clearly reduces helping speed and frequency. Strengths: Elegant manipulation of perceived group size; replicates bystander effect with different methodology. Limitations: Intercom setting lacks ecological validity; participants experienced genuine distress. Category: Cognitive