Group Differences in Personality and Intelligence: Individual Differences Lecture Notes

Canine Intelligence and Personality Trait Classifications

Foundational Literature on Canine Minds:
- The Intelligence of Dogs: Canine Consciousness and Capabilities by Stanley Coren.
- How Dogs Think: Understanding the Canine Mind by Stanley Coren.
Table 10.1: Ranking of Dogs for Obedience and Working Intelligence:
- Top Tier (Brightest Dogs):
  - 1: Border collie
  - 2: Poodle
  - 3: German shepherd
  - 4: Golden retriever
  - 5: Doberman pinscher
  - 6: Shetland sheepdog
  - 7: Labrador retriever
  - 8: Papillon
  - 9: Rottweiler
  - 10: Australian cattle dog
- High Intelligence:
  - 11: Pembroke Welsh corgi
  - 12: Miniature schnauzer
  - 13: English springer spaniel
  - 14: Belgian Tervuren
  - 15: Schipperke, Belgian sheepdog
  - 16: Collie, Keeshond
  - 17: German short-haired pointer
  - 18: Flat-coated retriever, English cocker spaniel, Standard schnauzer
  - 19: Brittany spaniel
  - 20: Cocker spaniel, Nova Scotia duck tolling retriever
  - 21: Weimaraner
  - 22: Belgian Malinois, Bernese mountain dog
  - 23: Pomeranian
  - 24: Irish water spaniel
  - 25: Vizsla
  - 26: Cardigan Welsh corgi
- Above Average/Lower Average Ranks:
  - 27: Chesapeake Bay retriever, Puli, Yorkshire terrier
  - 28: Giant schnauzer, Portuguese water dog
  - 29: Airedale, Bouvier des Flandres
  - 30: Border terrier, Briard
  - 31: Welsh springer spaniel
  - 32: Manchester terrier
  - 33: Samoyed
  - 34: Field spaniel, Newfoundland, Australian terrier, American Staffordshire terrier, Gordon setter, Bearded collie
  - 35: American Eskimo dog, Cairn terrier, Kerry blue terrier, Irish setter
  - 36: Norwegian elkhound
  - 37: Affenpinscher, Silky terrier, Miniature pinscher, English setter, Pharaoh hound, Clumber spaniel
  - 38: Norwich terrier
  - 39: Dalmatian
- Average Intelligence & Below:
  - 40: Soft-coated wheaten terrier, Bedlington terrier, Smooth-haired fox terrier
  - 41: Curly-coated retriever, Irish wolfhound
  - 42: Kuvasz, Australian shepherd
  - 43: Saluki, Finnish spitz, Pointer
  - 44: Cavalier King Charles spaniel, German wirehaired pointer, Black-and-tan coonhound, American water spaniel
  - 45: Siberian husky, Bichon frise, English toy spaniel
  - 46: Tibetan spaniel, English foxhound, Otterhound, American foxhound, Greyhound, Wirehaired pointing griffon
  - 47: West Highland white terrier, Havanese, Scottish deerhound
  - 48: Boxer, Great Dane
  - 49: Dachshund, Staffordshire bull terrier, Shiba Inu
  - 50: Malamute
  - 51: Whippet, Chinese shar-pei, Wirehaired fox terrier
  - 52: Rhodesian ridgeback
  - 53: Ibizan hound, Welsh terrier, Irish terrier
  - 54: Boston terrier, Akita
  - 55: Skye terrier
  - 56: Norfolk terrier, Sealyham terrier
  - 57: Pug
  - 58: French bulldog
  - 59: Brussels griffon, Maltese terrier
  - 60: Italian greyhound
  - 61: Chinese crested
  - 62: Dandie Dinmont terrier, Vendeen, Tibetan terrier, Japanese chin, Lakeland terrier
  - 63: Old English sheepdog
  - 64: Great Pyrenees
  - 65: Scottish terrier, Saint Bernard
  - 66: Bull terrier, Petite Basset Griffon Vendeen
  - 67: Chihuahua
  - 68: Lhasa apso
  - 69: Bullmastiff
  - 70: Shih Tzu
  - 71: Basset hound
  - 72: Mastiff, Beagle
  - 73: Pekingese
  - 74: Bloodhound
  - 75: Borzoi
  - 76: Chow chow
  - 77: Bulldog
  - 78: Basenji
  - 79: Afghan hound
- Note: Rankings with an asterisk () are based on scores from 70 to 99 obedience judges; unmarked rankings are based on 100 or more judges.*
Interpreting the Performance Rankings:
- Ranks 1 to 10 (The Brightest):
  - Understanding simple new commands: Less than $5$ exposures.
  - Habit retention: Remembered without noticeable need for practice.
  - Compliance: Obey the first command around $95\%$ of the time or better.
  - Response time: Respond within seconds, even at a distance.
  - Training: Effective even with inexperienced/inept trainers.
- Ranks 40 to 54 (Average Intelligence):
  - Understanding tasks: Show rudimentary understanding after $15$ to $20$ repetitions.
  - Compliance: Good performance requires quality training. Better handlers can make them appear elite; poorer handlers lacking patience can negatively impact performance.
Personality Traits in Domestic Dogs (Svartberg & Forkman, 2002): Evidence from the journal Applied Animal Behaviour Science identifies five narrow personality traits in dogs:
1. Playfulness
2. Curiosity/Fearlessness
3. Chase-proneness
4. Sociability
5. Aggressiveness

Theoretical Foundations of Group Differences in Intelligence

The Scope of Group Research (Maltby et al., Chapter 13):
- The focus is on heritability and socially defined group differences in intelligence.
- Research shifts from individual predictions to general statements about groups.
Rationale for Studying Group Differences:
- Typical psychological research looks for general statements rather than individual predictions.
- Economic Prediction: Understanding national average IQ has been used (controversially) to predict economic output.
- Biological Understanding: Analyzing group averages helps understand how sex hormones influence behavior and cognition.
- Practical Intervention: Identifying group-level patterns allows for the development of useful group-based interventions.
Limitations and Generalization:
- Group averages do not apply to every individual within the group.
- Individuals may feel dissatisfied when research prioritizes groups over individual nuance.
- Researchers must recognize significant "within-group differences."

Racial and Ethnic Groupings in Psychological Research

The Problem of Definition:
- Psychological science requires clear definitions, yet race lacks discrete boundaries.
- It is characterized as a continuum of genetic variations rather than "pure racial groups."
- In practice, social sciences often rely on self-identification via questionnaires.
The UK Census Classification System: Identification occurs in two stages, starting with five high-level categories:
- Asian, Asian British, Asian Welsh.
- Black, Black British, Black Welsh, Caribbean or African.
- Mixed or Multiple.
- White.
- Other ethnic group.
Historical Origins - Carl Linnaeus (18th Century): Linnaeus (1707-1778) originally classified humans into four groups:
- European (white)
- American (red)
- Asian (dark)
- African (black)
Terminology and Identity (Atkin et al., 2022):
- The term "Multiracial" is capitalized as a proper noun.
- Rationale: To recognize such individuals as a distinct group with unique racialized experiences and to challenge "monoracial structure" limitations.
Critical Inquiry into Race as a Variable:
- If used as a dependent variable, how is it defined? Potential markers include looks, genes, self-identification, ethnicity, geography, or a combination.
- Utility Debate: Is race helpful for cognitive/personality studies? We do not typically categorize by hair color or height/weight, raising questions about the necessity of race categorization.

The Scientific Debate: Race as Biology vs. Social Construction

The Social Constructionist View (Sternberg et al., 2005):
- "Race is a social construction, not a biological construct, and studies currently indicating alleged genetic bases of racial differences in intelligence fail to make their point even for these social-defined groups."
The Genetic Signal View (Hunt & Carlson, 2007):
- Argue that races do exist.
- Position: Ancestry patterns contain enough biological signal for "race" to serve as a biologically relevant, albeit "fuzzy/probabilistic," label.
- Advocate for 10 principles of design, analysis, and reporting to evaluate research carefully.
Historical Controversy (Arthur Jensen, 1969):
- Article: "How much can we boost IQ and scholastic achievement?"
- Key Claim: Poor scholastic performance among African Americans could be attributed to innate intelligence differences.
- Legacy: Led to the term "Jensenism," which became a code word for scientific racism.
Strategic Summaries of Theoretical Perspectives:
- Atkins et al.: Focused on language and treat "race as biology" as misleading; race labels should not be proxies for causal processes.
- Sternberg et al.: Focused on conceptual clarity and logical limits of what heritability can justify; separates science from policy.
- Hunt & Carlson: Defends studying group differences as legitimate but high-stakes, requiring extreme methodological care.

Sex and Gender: Definitions and Biological Basis

Differentiating Sex and Race:
- Sex is a clearly defined concept, whereas race is difficult to define.
- Sex is not confounded by nationality or socio-economic status (SES), while race is severely confounded by SES.
Biological Basis of Sex:
- Determined by sex chromosomes: $XX$ (Female) and $XY$ (Male).
- Influenced by exposure to different quantities of sex hormones at specific developmental periods.
- Hormones control body/brain development and functioning.
Defining Gender:
- No single agreed-upon definition across psychology, sociology, and biology.
- Often used interchangeably with "sex" in practice.
- Typically refers to social activities associated with the two sexes.
- "Gender role" is considered a more precise term.
Chromosomal and Hormonal Syndromes:
- Klinefelter Syndrome: Characterized by $XXY$ chromosomes; occurs in approximately $1:500-1000$ .
- Turner Syndrome: Characterized by a single $X$ chromosome; occurs in approximately $1:2000-5000$ .
- Congenital Adrenal Hyperplasia (CAH): A disorder involving sex hormones.
- Androgen/Estrogen Insensitivity Syndrome: Tissues are unable to respond to sex hormones.
Terminology on Identity:
- Intersex: Not an official medical term; refers to ambiguous or opposite primary sex organs.
- Transgender: Refers to individuals who wish to be a different sex than they are genetically.

Sex Differences in Cognitive Abilities and Interests

Language and Verbal Skills:
- Girls generally speak earlier than boys.
- By age one, girls know more words than boys.
- At age 15, girls are better at understanding texts (Stoet & Geary, 2012-2020).
- Women hold an advantage in verbal episodic memory (Lewin et al., 2001).
- Caveat: Some language skill differences disappear with age (Wallentin, 2009).
- Caveat: Talkativeness depends on the specific situation (Leaper & Ayres, 2007).
- Brain Organization: Language functions are organized differently in the brains of men and women (Shaywitz et al., 1995).
Spatial Skills:
- Boys and men have a small-to-moderate advantage in navigation (Voyer et al., 2019).
- Men perform significantly better in mental rotation tasks (Collins & Kimura, 1997).
Vocational Interests (Su, Rounds, & Armstrong, 2009):
- Meta-analysis of 47 inventories and $503,188$ respondents.
- Things-People Dimension: Large effect size of $d = 0.93$ . Men prefer working with things; women prefer working with people.
- Men's Primary Interests: Realistic ( $d = 0.84$ ) and Investigative ( $d = 0.26$ ).
- Women's Primary Interests: Social ( $d = -0.68$ ), Artistic ( $d = -0.35$ ), and Conventional ( $d = -0.33$ ).
- STEM Specifics: Differences favoring men in engineering ( $d = 1.11$ ), science ( $d = 0.36$ ), and mathematics ( $d = 0.34$ ).
Hormonal Influences on Occupational Interest (Beltz et al., 2011):
- Study of individuals with Congenital Adrenal Hyperplasia (CAH) who have atypical prenatal androgen exposure.
- Females with CAH showed significantly more interest in "Things" versus "People" than unaffected females.
- Variations in interest levels among CAH females reflected their specific degree of androgen exposure.
- Conclusion: Hormones contribute to interest in occupations characterized by working with things.

Critical Thinking and Future Considerations

The Validity of Racial Groupings:
- Given the lack of "pure" races and increased global travel, will racial groupings remains valid in the future?
- What information is actually gained from studying the intersection of cognition and race differences?
Methodological Caution:
- Hunt & Carlson emphasize that researching racial/ethnic differences is important but potentially divisive.
- The research community should defend high-quality research regardless of the popularity of findings, but should not defend structurally bad research.