samples

---

1. Biological Approach

• Dement and Kleitman (1957):

---

• 9 adults (7 males, 2 females); 5 were studied intensely, while 4 were used to confirm data.

Here is the finalized list of the 12 core studies and their specific participant samples for your 2025 exams:

---

1. Biological Approach

• Dement and Kleitman (1957): 9 adults (7 males, 2 females); 5 were studied intensely, while 4 were used to confirm data.

• Hassett et al. (2008): 82 rhesus monkeys (Macaca mulatta) living in a social group at the Yerkes National Primate Research Center.

• Hölzel et al. (2011): 33 healthy participants (16 in the MBSR mindfulness group, 17 in the control group).

2. Cognitive Approach

• Andrade (2010): 40 participants (aged 18–55) from a university participant panel (mostly females).

• Baron-Cohen et al. (2001): 4 groups, including 15 adults with AS/HFA and 122 "normal" adults from the general population.

• Pozzulo et al. (2011): 590 participants total (414 children aged 4–13 and 176 adults aged 17–30).

3. Learning Approach

• Bandura et al. (1961): 72 children (36 boys, 36 girls) from the Stanford University Nursery School (mean age 4.3 years).

• Fagen et al. (2014): 5 female Asian elephants (Elephas maximus) at a rehabilitation center in South Korea.

• Saavedra and Silverman (2002): A single 9-year-old Hispanic American boy (Case Study).

4. Social Approach

• Milgram (1963): 40 males, aged 20–50, from the New Haven area, recruited through a newspaper ad.

• Perry et al. (2015): 66 female students from the University of Haifa (32 in the "high empathy" group, 34 in the "low empathy" group).

• Piliavin et al. (1969): Approximately 4,450 passengers on the New York subway (55% white, 45% black).

---

Important for your March/June 2025 Exams:

When studying these for Paper 1 and Paper 2, remember that you are often asked for two specific features of a sample (e.g., "40 participants" and "aged 18–55"). For the animal studies (Hassett, Fagen, and Pepperberg—though Pepperberg is no longer a core study in the 2024–26 list, having been replaced by Fagen), you must know the species and the housing conditions.