Contemporary study (depression option): Ma, Quan and Liu (2014)

Aims and sample

Aims: to see whether core self-evaluation negatively predicts depression and positively predicts perceived social support, and whether social support mediates (explains part of) the link between self-evaluation and depression.

Sample: 538 university students in China (281 female, 257 male), mean age 19.4 (SD 2.8). A volunteer sample recruited through online forums, with no payment; informed consent was given online first.

Procedure

An online survey with no time limit; IP addresses were checked to stop people taking part twice.

• Core Self-Evaluations Scale (CSES): 12 items, 5-point scale (self-esteem, self-efficacy, neuroticism, locus of control).
• Multidimensional Scale of Perceived Social Support (MSPSS): 12 items, 7-point scale (family, friends, significant others).
• Zung Self-Rating Depression Scale (SDS): 20 items, 4-point scale.

The scales had good internal reliability (Cronbach's alpha above .8).

Results and conclusions

Correlations: self-evaluation and depression r = -.636; self-evaluation and social support r = .365; social support and depression r = -.375.

In regression, the effect of self-evaluation on depression was -0.636 on its own and -0.457 with social support included. The difference, -0.179, is the mediating effect: social support partly mediates the link.

Conclusion: positive self-evaluation may make it easier to seek and perceive social support, which is linked to less severe depression.

Evaluation

• Standardised, pre-tested scales with good reliability (credited by examiners).
• Large sample, but university student volunteers recruited online: limited generalisability.
• Correlational: mediation analysis cannot prove cause.
• Self-report: social desirability and honesty about mood.
• Application: interventions could build social support and self-evaluation; supports cognitive explanations like Beck's (negative view of self).

Worked example

Self-evaluation predicted depression with beta = -0.636 alone and -0.457 when social support was added. What proportion of the effect is explained by social support?

1. Mediating effect = -0.636 - (-0.457) = -0.179.
2. Proportion = 0.179 / 0.636 = 0.281.
3. So about 28.1% of the effect runs through social support: partial mediation.

Answer: About 28.1%: social support explains part, not all, of the link.

Check yourself

1. Calculate the mediating effect: -0.636 minus (-0.457). Give your answer to 3 decimal places.
   Show answer

   -0.179. -0.636 - (-0.457) = -0.179.

2. What percentage of the 538 participants were female (281)? Give your answer to 1 decimal place.
   Show answer

   52.2 %. 281 / 538 x 100 = 52.2%.

3. What does r = -.636 between self-evaluation and depression mean?
   • A fairly strong negative correlation: higher self-evaluation goes with lower depression
   • A weak positive correlation
   • Self-evaluation causes depression
   • No relationship
   Show answer

   A fairly strong negative correlation: higher self-evaluation goes with lower depression. Negative sign, size above .6.

4. What sampling method did Ma, Quan and Liu use?
   • Stratified sampling of hospital patients
   • Random sampling from a national register
   • Opportunity sampling in a shopping centre
   • Volunteer sampling through online forums
   Show answer

   Volunteer sampling through online forums. Students volunteered online.

5. What does it mean that social support 'partly mediates' the link?
   • Social support causes self-evaluation
   • Part of the link between self-evaluation and depression is explained through social support
   • Social support has no role
   • Depression causes social support
   Show answer

   Part of the link between self-evaluation and depression is explained through social support. The direct effect shrinks but does not disappear.

6. Explain one weakness of Ma, Quan and Liu's (2014) method.
   Show answer

   It used self-report questionnaires, so students might give socially desirable answers about their mood and support, which reduces validity.. Self-report bias, sampling or correlation.

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Sources

• Pearson Edexcel International Advanced Subsidiary/Advanced Level in Psychology specification (issue January 2026)
• Pearson IAL Psychology component guide: WPS04 (Issue 2, November 2024)
• Pearson IAL Psychology summary of studies: WPS04
• Pearson WPS04/01 examiners' report, June 2025

Last updated 8 November 2026. Spotted a mistake? Tell us.