📚 IGCSE CCEA Psychology: Key Points for Experimental/Practical Assessment | IGCSE CCEA 心理学：实验/实践考核要点
The experimental and practical component of IGCSE CCEA Psychology tests your ability to design, carry out, analyse and evaluate a psychological investigation. You may be asked to plan a study, write up a report, or answer structured questions on research methods.
IGCSE CCEA 心理学的实验与实践部分考查你设计、实施、分析和评价一项心理学研究的能力。你可能会被要求计划一项研究、撰写报告，或回答有关研究方法的 structured 问题。
Strong answers demonstrate accurate use of key terms, clear operationalisation of variables, justified design choices, and critical evaluation of strengths and limitations rather than simple description.
优秀答案展示了对关键术语的准确使用、变量的清晰操作性定义、合理的设计选择，以及对优点和局限性的批判性评价，而不是简单描述。
1. Understanding the Assessment Format | 理解考核形式
In the CCEA Psychology practical assessment, marks are typically awarded for selecting an appropriate design, describing procedures, controlling variables, applying ethical guidelines, presenting data, and evaluating findings.
在 CCEA 心理学实践考核中，分数通常给予选择合适的设计、描述程序、控制变量、应用伦理准则、呈现数据和评价研究结果。
You should be familiar with the command words used in practical questions, such as “state”, “describe”, “explain”, “justify” and “evaluate”. Each command word requires a different depth of response.
你应当熟悉实践题中常用的指令词，例如 “state”、”describe”、”explain”、”justify” 和 “evaluate”。每个指令词需要不同深度的回答。
A complete practical write-up usually includes an aim, hypothesis, method, results, conclusion and evaluation. Missing any section can cost marks even if the experiment itself is well planned.
一份完整的实践报告通常包括研究目的、假设、方法、结果、结论和评价。即使实验本身计划得很好，缺少任何部分都可能丢分。
2. Aims and Hypotheses | 研究目的与假设
A research aim is a broad statement of what the study intends to investigate, for example “to investigate the effect of noise on memory”. A hypothesis must be a precise, testable prediction stating the expected relationship between variables.
研究目的是对研究意图的宽泛陈述，例如“研究噪音对记忆的影响”。假设必须是一个精确、可检验的预测，说明变量之间预期的关系。
A directional hypothesis predicts the direction of the effect, such as “participants in quiet conditions will recall more words than participants in noisy conditions”. A non-directional hypothesis simply predicts a difference without stating direction.
方向性假设预测效应的方向，例如“安静条件下的参与者将比嘈杂条件下的参与者回忆更多单词”。非方向性假设只预测存在差异，但不说明方向。
The null hypothesis predicts no effect or no difference between conditions. It is the hypothesis that statistical tests usually attempt to reject.
零假设预测条件之间没有效应或没有差异。统计检验通常试图拒绝零假设。
H₁: recall in quiet condition > recall in noise condition; H₀: recall in quiet condition = recall in noise condition
3. Variables and Operationalisation | 变量与操作性定义
The independent variable (IV) is the variable the researcher manipulates, and the dependent variable (DV) is the variable the researcher measures. Extraneous variables are any other variables that could affect the DV and must be controlled.
自变量 (IV) 是研究者操纵的变量，因变量 (DV) 是研究者测量的变量。额外变量是可能影响因变量的任何其他变量，必须加以控制。
Operationalising variables means stating exactly how each variable will be manipulated or measured in observable, repeatable units. For example, “noise” is too vague, but “80 dB white noise played through headphones” is operationalised.
操作性定义变量意味着准确说明每个变量将如何以可观察、可重复的单位进行操纵或测量。例如，“噪音”太模糊，而“通过耳机播放 80 分贝白噪音”就是操作性定义。
| Independent variable (IV) – manipulated / 自变量 – 被操纵 | Dependent variable (DV) – measured / 因变量 – 被测量 |
| Extraneous variable – unwanted variable / 额外变量 – 不希望出现的变量 | Confounding variable – uncontrolled and affects DV / 混淆变量 – 未被控制且影响因变量 |
A poor operationalisation makes results impossible to replicate. In the exam, always state the units, condition levels, or scoring method for each variable.
糟糕的操作性定义使结果无法重复。在考试中，务必说明每个变量的单位、条件水平或计分方法。
4. Experimental Designs | 实验设计
Independent groups design uses different participants in each condition. It avoids order effects but may be affected by participant variables such as individual differences in ability.
独立组设计在每个条件下使用不同的参与者。它避免了顺序效应，但可能受到参与者变量的影响，例如个体能力差异。
Repeated measures design uses the same participants in all conditions. It controls participant variables but risks order effects such as practice or fatigue.
重复测量设计在所有条件下使用相同的参与者。它控制了参与者变量，但存在练习或疲劳等顺序效应的风险。
Matched pairs design uses different but similar participants, who are matched on a relevant characteristic before being allocated to conditions. It reduces participant variables and order effects but is time-consuming.
配对组设计使用不同但相似的参与者，在分配条件前根据相关特征进行匹配。它减少了参与者变量和顺序效应，但耗时较长。
| Design / 设计 | Strength / 优点 | Limitation / 局限 |
|---|---|---|
| Independent groups / 独立组 | No order effects / 无顺序效应 | Participant variables / 参与者变量 |
| Repeated measures / 重复测量 | Fewer participants; controls participant variables / 参与者更少；控制参与者变量 | Order effects / 顺序效应 |
| Matched pairs / 配对组 | Controls participant variables; no order effects / 控制参与者变量；无顺序效应 | Time-consuming; matching is imperfect / 耗时；匹配不完美 |
5. Sampling Methods | 抽样方法
Random sampling gives every member of the target population an equal chance of being selected. It reduces sampling bias but is often difficult to achieve in a school setting.
随机抽样使目标人群中的每个成员都有平等被选中的机会。它减少了抽样偏差，但在学校环境中通常难以实现。
Opportunity sampling uses people who are readily available at the time, such as classmates. It is quick and convenient but may be unrepresentative of the wider population.
机会抽样使用当时容易找到的人，例如同学。它快速方便，但可能不能代表更广泛的人群。
Stratified sampling divides the population into subgroups, such as age bands or year groups, and then randomly samples from each subgroup in proportion. It is representative but complex to organise.
分层抽样将人群分为亚组，例如年龄组或年级组，然后按比例从每个亚组中随机抽取样本。它具代表性，但组织起来较复杂。
Systematic sampling selects every nth person from a list. It is simple and spreads the sample across the population, but if the list has a hidden order, bias can occur.
系统抽样从名单中每隔 n 个人选取一个。它简单且能覆盖整个人群，但如果名单存在隐藏顺序，就可能产生偏差。
Volunteer sampling relies on people choosing to take part. It is ethical and convenient but often attracts a biased sample of highly motivated participants.
志愿者抽样依赖于人们选择参与。它合乎伦理且方便，但往往吸引的是动机很强的参与者，造成样本偏差。
6. Controls and Validity | 控制与效度
Standardised procedures ensure every participant experiences exactly the same instructions, materials and timings, except for the IV. This increases reliability and internal validity.
标准化程序确保除自变量外，每个参与者接受完全相同的指导语、材料和计时。这提高了信度和内部效度。
Random allocation to conditions helps control participant variables in independent groups designs. Counterbalancing is used in repeated measures designs to control order effects by varying the order of conditions.
随机分配条件有助于在独立组设计中控制参与者变量。平衡法用于重复测量设计，通过改变条件顺序来控制顺序效应。
Internal validity refers to whether the IV truly caused the change in the DV. External validity, including ecological validity, refers to whether findings can be generalised to real-life settings.
内部效度指因变量的变化是否真正由自变量引起。外部效度，包括生态效度，指研究结果能否推广到现实生活情境。
One common threat to validity is demand characteristics, where participants change their behaviour because they guess the aim of the study. Using a single-blind procedure can reduce this problem.
效度的一个常见威胁是需求特征，即参与者因为猜到研究目的而改变行为。使用单盲程序可以减少这一问题。
7. Ethical Guidelines | 伦理准则
All practical work in CCEA Psychology must follow ethical principles. These protect the welfare, dignity and rights of participants and are frequently assessed in practical questions.
CCEA 心理学中所有实践工作都必须遵循伦理原则。这些原则保护参与者的福祉、尊严和权利，在实践题中经常被考查。
Informed consent means participants should know the aim and nature of the study before agreeing to take part. For participants under 16, consent from a parent or guardian is usually required.
知情同意意味着参与者在同意参与前应了解研究目的和性质。对于 16 岁以下的参与者，通常需要父母或监护人的同意。
Participants have the right to withdraw from the study at any time, and their data must be removed if they request this. Confidentiality means personal information should be anonymised in the report.
参与者有权随时退出研究，如果他们要求，其数据必须被删除。保密性意味着报告中个人信息应匿名化。
Deception should be avoided where possible. If mild deception is necessary, participants must be fully debriefed afterwards and given the chance to withhold their data.
应尽可能避免欺骗。如果必须使用轻度欺骗，事后必须向参与者充分说明，并允许他们撤回数据。
Participants must be protected from physical and psychological harm, including stress, embarrassment or pressure. A risk assessment should be carried out before the study begins.
必须保护参与者免受身体和心理伤害，包括压力、尴尬或强迫。在研究开始前应进行风险评估。
8. Data Collection and Analysis | 数据收集与分析
Quantitative data are numerical and allow easy comparison, averages and graphs. Qualitative data are descriptive, such as interview transcripts or observations, and provide richer detail but are harder to analyse.
定量数据是数字形式，便于比较、计算平均数和绘制图表。定性数据是描述性的，如访谈记录或观察，提供更丰富的细节，但更难分析。
The mean is calculated by adding all scores and dividing by the number of scores. The median is the middle value when scores are ordered, and the mode is the most frequent score.
平均数是将所有分数相加后除以分数的个数。中位数是分数排序后的中间值，众数是出现最频繁的分数。
Mean = Σx ÷ n; Range = max − min
The range is the difference between the highest and lowest scores. It gives a quick measure of spread but is easily distorted by extreme values.
全距是最高分与最低分之间的差。它能快速衡量离散程度，但容易被极端值扭曲。
Bar charts are used for categorical data, histograms for continuous data, and scatter graphs for showing correlations between two measured variables.
条形图用于分类数据，直方图用于连续数据，散点图用于显示两个测量变量之间的相关关系。
9. Drawing Conclusions and Evaluating | 得出结论与评价
In the conclusion, you must state whether the hypothesis was supported, refer to the data, and avoid claiming proof. In psychology, results support or fail to support a hypothesis; they do not prove it.
在结论中，必须说明假设是否得到支持，引用数据，并避免声称证明了假设。在心理学中，结果支持或不支持假设；它们不能证明假设。
Evaluation should consider reliability, which is the consistency of the measurement, and validity, which is whether the study measured what it intended to measure.
评价应考虑信度，即测量的一致性，以及效度，即研究是否测量了它想要测量的内容。
Generalisability refers to whether the findings can be applied to the target population. A small, unrepresentative sample limits generalisability.
可推广性指研究结果能否应用于目标人群。样本小且不具代表性会限制可推广性。
You should suggest at least one realistic improvement, such as increasing the sample size, using a matched pairs design, or standardising the instructions more carefully.
你应至少提出一项切实可行的改进建议，例如增加样本量、使用配对组设计，或更仔细地标准化指导语。
A critical evaluation must link limitations to the actual study. For example, if a repeated measures design was used, state that order effects may have influenced the second condition.
批判性评价必须将局限性与实际研究联系起来。例如，如果使用了重复测量设计，应指出顺序效应可能影响了第二个条件。
10. Common Pitfalls in the Practical Exam | 实践考核常见失分点
A common mistake is failing to operationalise the IV or DV, for example writing “memory” instead of “number of words correctly recalled from a 20-word list”.
一个常见错误是未能对自变量或因变量进行操作定义，例如写“记忆”，而不是“从 20 个单词列表中正确回忆的单词数量”。
Confusing experimental designs is another frequent error. You must know which design fits the procedure and be able to justify its selection rather than merely naming it.
混淆实验设计是另一个常见错误。你必须知道哪种设计适合该程序，并能够说明选择的理由，而不只是说出名称。
Ignoring extraneous variables and ethical issues will weaken the method section. Always identify at least one control and one ethical safeguard relevant to the study.
忽略额外变量和伦理问题会削弱方法部分。务必找出至少一个与研究相关的控制措施和一个伦理保护措施。
Describing results without referring to the hypothesis or without statistical awareness often limits the conclusion. Link findings back to the aim and hypothesis explicitly.
描述结果但不提及假设，或缺乏统计意识，通常会限制结论。要将研究结果明确地与目的和假设联系起来。
Finally, evaluation that is only positive misses the critical edge. Examiners reward balanced evaluation that identifies both strengths and weaknesses.
最后，只有正面评价会失去批判性。考官奖励能同时指出优点和弱点的平衡评价。
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