📚 IGCSE AQA Psychology: Key Points for Experiment/Practical Assessment | IGCSE AQA 心理学：实验/实践考核要点
Mastering experimental methods is the cornerstone of success in IGCSE AQA Psychology. Whether you are designing a study, evaluating research, or tackling exam questions, a clear grasp of variables, designs, controls, ethics, and practical skills is essential. This guide breaks down every key point you need for the experiment/practical assessment component, pairing concise English explanations with Chinese translations to support your revision.
掌握实验方法是 IGCSE AQA 心理学取得成功的基础。无论你是在设计研究、评估研究还是应对考试题目，清晰掌握变量、实验设计、控制条件、伦理规范和实践技能都至关重要。本指南逐一解析实验/实践考核所需的每一个要点，提供简洁的英文解释与中文翻译，助力你的复习。
1. The Experimental Method | 实验法
The experimental method is the only research method in psychology that can establish cause-and-effect relationships. It involves the deliberate manipulation of an independent variable (IV) to observe its effect on a dependent variable (DV), while all other variables are controlled.
实验法是心理学中唯一能够确立因果关系的研究方法。它涉及有意地操纵自变量（IV）以观察其对因变量（DV）的影响，同时控制所有其他变量。
IGCSE candidates must be able to distinguish between laboratory experiments, where the environment is tightly controlled, and field experiments, where the IV is manipulated in a natural setting. You should evaluate each in terms of control, ecological validity, demand characteristics, and generalisability. Natural experiments and quasi-experiments are also relevant but the focus remains on true experiments where the researcher directly changes the IV.
IGCSE 考生必须能够区分实验室实验（环境受到严格控制）和现场实验（在自然环境中操纵自变量）。你应从控制程度、生态效度、需求特征和可推广性等方面进行评价。自然实验和准实验也相关，但重点仍是研究者直接改变自变量的真实验。
2. Variables and Hypothesis | 变量与假设
An independent variable (IV) is the factor manipulated by the researcher. A dependent variable (DV) is the factor measured to assess the effect of the IV. Control variables are kept constant to prevent them from influencing the DV, while confounding variables are uncontrolled factors that could distort the results. Operationalisation means defining variables in clear, measurable terms so the study can be replicated.
自变量（IV）是研究者操纵的因素。因变量（DV）是为评估 IV 效果而测量的因素。控制变量保持恒定以防止它们影响 DV，而混淆变量是可能扭曲结果的不受控因素。操作化是指用清晰、可测量的术语定义变量，以便研究可被重复。
In the exam, you may be asked to write a suitable hypothesis. An experimental (alternative) hypothesis predicts a difference or relationship. It can be directional (one-tailed), specifying the expected direction of the effect, or non-directional (two-tailed), simply stating there will be a difference. The null hypothesis states there will be no difference. Always operationalise the IV and DV in your hypothesis.
考试中可能会要求你写出合适的假设。实验假设（备择假设）预测存在差异或关系。它可以是方向性的（单尾），明确指出预期效果的方向；也可以是非方向性的（双尾），仅表述会有差异。零假设则表述不会有差异。务必在假设中将 IV 和 DV 操作化。
3. Experimental Designs | 实验设计类型
Independent groups design uses different participants in each condition. Its strength is the absence of order effects; however, participant variables can act as confounds, and more participants are required. Random allocation is critical.
独立组设计在每种条件下使用不同的参与者。其优点是没有顺序效应；然而，参与者变量可能成为混淆变量，且需要更多参与者。随机分配至关重要。
Repeated measures design uses the same participants in all conditions. This controls participant variables and requires fewer participants, but order effects such as practice and fatigue can bias the results. Counterbalancing (e.g., ABBA) is used to control order effects.
重复测量设计在所有条件下使用相同的参与者。这控制了参与者变量且所需参与者较少，但练习效应和疲劳效应等顺序效应可能使结果产生偏差。常使用平衡法（如 ABBA）来控制顺序效应。
Matched pairs design pairs participants on a key trait and assigns one to each condition. It reduces participant variables without order effects, but matching is time-consuming and may be imperfect.
匹配对设计将参与者在关键特质上进行配对，然后分别分配到不同条件。它减少了参与者变量且无顺序效应，但匹配耗时且可能不完美。
| Design | Key Feature | Strength | Limitation |
|---|---|---|---|
| Independent Groups | Different participants per condition | No order effects | Participant variables, more participants |
| Repeated Measures | Same participants in all conditions | Controls participant variables, fewer participants | Order effects, demand characteristics |
| Matched Pairs | Participants paired on relevant traits | Reduces participant variables, no order effects | Difficult matching, time-consuming |
This table summarises the three experimental designs: independent groups, repeated measures, and matched pairs. Selecting the most appropriate design for a given scenario and justifying your choice is a common practical assessment task.
上表总结了三种实验设计：独立组、重复测量和匹配对。选择最适合特定场景的设计并论证你的选择，是常见的实践评估任务。
4. Controlling Extraneous Variables | 控制额外变量
Extraneous variables are any factors other than the IV that could affect the DV. If not controlled, they become confounding variables, reducing internal validity. Control methods include randomisation, standardised procedures, and single-blind or double-blind techniques.
额外变量是除 IV 外任何可能影响 DV 的因素。若不加以控制，它们就会成为混淆变量，降低内部效度。控制方法包括随机化、标准化程序以及单盲或双盲技术。
Random allocation to conditions reduces participant variables in independent groups designs. In repeated measures, counterbalancing controls order effects. Standardised instructions and scripts ensure all participants are treated identically. A single-blind procedure keeps participants unaware of the condition they are in; a double-blind procedure also keeps the researcher unaware, controlling for investigator effects.
随机分配条件可减少独立组设计中的参与者变量。在重复测量中，平衡法控制顺序效应。标准化指导语和脚本确保所有参与者被等同对待。单盲程序让参与者不知道所在的条件；双盲程序还使研究者也不知情，从而控制研究者效应。
5. Sampling Methods | 取样方法
Opportunity sampling selects participants who are readily available at the time. It is quick and convenient, but the sample may be unrepresentative, leading to researcher bias.
机会取样选取当时最容易找到的参与者。它快捷方便，但样本可能不具代表性，导致研究者偏差。
Random sampling gives every member of the target population an equal chance of selection, reducing bias. However, it requires a complete list of the population and may still yield an unrepresentative sample by chance.
随机取样使目标总体中每个成员都有相等被选中的机会，减少偏差。然而，它需要完整的总体名单，且可能偶然产生不具代表性的样本。
Stratified sampling identifies subgroups (strata) within the population and selects participants in proportion to their representation. It provides a highly representative sample but is time-consuming and complex.
分层取样识别总体中的子群（层），并按比例选取参与者。它提供的样本代表性很高，但耗时且复杂。
Systematic sampling selects every nth individual from a list. It is straightforward but can introduce bias if the list has a hidden order.
系统取样从名单中每隔 n 个选取一个个体。它简单直接，但如果名单存在隐藏顺序，可能引入偏差。
Volunteer (self-selected) sampling relies on participants offering to take part, often through advertisements. It is easy but suffers from volunteer bias, as those who volunteer may differ from the general population.
志愿者（自选）取样依赖参与者主动报名，常通过广告。它容易实施，但存在志愿者偏差，因为志愿者可能与一般人群不同。
6. Ethical Guidelines | 伦理指导原则
Informed consent means participants should know the aims and procedures of the study and agree to take part. For those under 16, parental consent is required. Where full disclosure might affect behaviour, presumptive consent or prior general consent can be used.
知情同意意味着参与者应知晓研究的目的和程序并同意参与。对于 16 岁以下者，需要家长同意。在完全告知可能影响行为时，可使用推定同意或事先一般同意。
Deception should be avoided unless it is essential and there is no alternative. When deception is used, participants must be thoroughly debriefed afterwards, explaining the true purpose and restoring their wellbeing.
应避免欺骗，除非它必不可少且无其他替代方法。使用了欺骗时，必须在事后对参与者进行彻底的事后说明，解释真实目的并恢复其福祉。
The right to withdraw allows participants to leave the study at any time without giving a reason and without penalty. They can also request that their data be removed.
退出权利允许参与者在任何时间退出研究，无需给出理由且不受任何惩罚。他们还可以要求删除自己的数据。
Protection from harm means participants must not experience physical or psychological stress beyond what they encounter in everyday life. Researchers must stop the study if harm is suspected.
免受伤害意味着参与者承受的身体或心理压力不得超过日常生活中的程度。若怀疑存在伤害，研究者必须停止研究。
Confidentiality must be maintained: personal data should be anonymised, and participants’ identities should not be revealed in reports.
必须保密：个人数据应匿名处理，报告中不应透露参与者的身份。
7. Standardisation and Pilot Studies | 标准化与试点研究
Standardisation means keeping the procedure identical for all participants, including instructions, timing, environment, and materials. This ensures that any measured differences in the DV can be attributed to the IV, making replication possible.
标准化意味着让所有参与者的程序保持一致，包括指导语、时间安排、环境和材料。这确保了 DV 的任何测量差异都可归因于 IV，并使研究可被重复。
A pilot study is a small-scale trial run before the main study. It helps identify potential problems with the procedure, materials, or measurement tools. For example, a pilot can reveal ambiguous instructions or confounding variables, allowing the researcher to refine the design and improve validity.
试点研究是主研究前的小规模试运行。它有助于发现程序、材料或测量工具的潜在问题。例如，试点可揭示模棱两可的指导语或混淆变量，使研究者能优化设计并提高效度。
8. Data Collection Techniques | 数据收集方法
Within an experiment, data can be collected through structured observations using behavioural checklists, questionnaires measuring attitudes or self-report, physiological measures (e.g., heart rate), and performance on cognitive tasks.
在实验中，数据可通过使用行为检查表的结构化观察、测量态度或自我报告的问卷、生理测量（如心率）以及认知任务表现等方式收集。
Operationalising behavioural categories is crucial in observations. Categories must be specific, observable, and mutually exclusive. For example, ‘aggression’ might be operationalised as ‘hitting, kicking, or shouting at another person’.
在观察中，将行为类别操作化至关重要。类别必须具体、可观察且互斥。例如，“攻击性”可操作化为“击打、踢打或对他人喊叫”。
Self-report measures such as Likert scales allow researchers to quantify attitudes. However, social desirability bias may lead participants to respond in ways they think are acceptable, reducing validity.
自陈量具如李克特量表使研究者能量化态度。然而，社会期望偏差可能导致参与者按他们认为可接受的方式回答，降低效度。
9. Assessing Validity and Reliability | 评估效度与信度
Internal validity concerns whether the IV genuinely caused the observed change in the DV, free from confounding variables. Threats include demand characteristics, investigator effects, and uncontrolled extraneous variables.
内部效度关注 IV 是否确实导致所观察到的 DV 变化，且不受混淆变量影响。威胁包括需求特征、研究者效应和未控制的额外变量。
External validity refers to the extent findings can be generalised beyond the study. Ecological validity is how well the task and setting reflect real life; population validity considers whether the sample represents the target population.
外部效度指研究发现可推广到研究之外的程度。生态效度是任务和环境反映现实生活的程度；总体效度考虑样本是否代表目标总体。
Reliability is the consistency of measurement. Test-retest reliability checks whether the same participants score similarly on a measure on two separate occasions. Inter-rater reliability is important in observations, where two observers independently rate the same behaviours and their ratings are correlated.
信度是测量的一致性。重测信度检验相同参与者在两个不同时间点在同一量具上的得分是否相似。评分者信度在观察中很重要，即两名观察者独立对相同行为进行评分，并计算其评分之间的相关性。
10. Practical Assessment Skills in AQA IGCSE | AQA IGCSE 中的实践评估技能
In AQA IGCSE Psychology, practical questions often ask you to design an experiment. A strong response includes: a fully operationalised hypothesis (including the null hypothesis); identification of the experimental design with a clear justification; a detailed description of the sample and sampling method; a step-by-step standardised procedure; a description of controls and how confounding variables will be minimised; and an outline of ethical considerations.
在 AQA IGCSE 心理学中，实践题常要求你设计一个实验。高分答案应包含：完全操作化的假设（包括零假设）；明确实验设计并给出清晰理由；详细描述样本和取样方法；逐步标准化程序；描述控制条件及如何将混淆变量降至最低；并概述伦理考量。
Evaluation (AO3) is crucial. You must discuss strengths and limitations of your chosen design, sampling, and control. For example, if you used independent groups, you could comment that random allocation reduces participant variables but individual differences may still affect the DV. Always suggest realistic improvements.
评估（AO3）至关重要。你必须讨论所选设计、取样和控制的优缺点。例如，若使用了独立组设计，你可以评论随机分配减少了参与者变量，但个体差异仍可能影响 DV。务必提出切实可行的改进建议。
11. Common Mistakes and Examiner Tips | 常见错误与考官建议
One frequent error is misidentifying the IV and DV or failing to operationalise them. Never write an IV like ‘memory’ without specifying how it will be manipulated (e.g., ‘number of words in a list’).
常见错误之一是误认 IV 和 DV 或未将其操作化。不要只写一个像“记忆”这样的 IV 而不说明它将如何被操纵（例如，“列表中的单词数量”）。
Many students forget to control order effects in repeated measures designs. Always mention counterbalancing (e.g., half the participants do condition A then B, the other half do B then A).
许多学生忘记在重复测量设计中控制顺序效应。一定要提到平衡法（例如，一半参与者先做条件 A 再做 B，另一半先做 B 再做 A）。
Ethics are often overlooked in design questions. Even a brief note about gaining consent, ensuring the right to withdraw, and a debrief plan can earn marks.
伦理问题在设计题中常被忽略。即使只是简要提及获得同意、确保退出权利以及事后说明计划，也能获得分数。
When evaluating, simply listing strengths and limitations is not enough. You must explain why something is a strength or limitation and link it to the context. For instance, ‘volunteer sampling is quick but may lead to a biased sample because only certain types of people volunteer, so findings may lack population validity.’
评估时，仅仅列出优缺点是不够的。你必须解释为什么某点是优点或缺点，并将其与情境联系起来。例如，“志愿者取样快速，但可能导致有偏差的样本，因为只有特定类型的人会自愿参加，因此结果可能缺乏总体效度。”
12. Key Command Words | 关键指令词
Understanding command words maximises your marks. ‘State’ or ‘Identify’ requires a brief, one-sentence answer. ‘Describe’ needs a detailed account of the procedure or findings. ‘Explain’ requires you to say why or how something happens, linking cause and effect.
理解指令词能让你拿到最高分。“陈述”或“指出”只需要简短的、一句话的答案。“描述”需要对程序或发现做出详细叙述。“解释”需要你说明某事为何或如何发生，将因果联系起来。
‘Evaluate’ means you must discuss both strengths and limitations and reach a supported conclusion. ‘Design’ requires you to create a full plan, from hypothesis to ethical considerations, as described in Section 10. Always check how many marks a question is worth and adjust the depth of your answer accordingly.
“评价”意味着你必须讨论优点和局限性，并得出有依据的结论。“设计”则要求你创建一个完整的计划，从假设到伦理考量，如第 10 节所述。始终根据题目的分值调整答案的深度。
Published by TutorHao | Psychology Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
屏轩国际教育cambridge primary/secondary checkpoint, cat4, ukiset,ukcat,igcse,alevel,PAT,STEP,MAT, ibdp,ap,ssat,sat,sat2课程辅导，国外大学本科硕士研究生博士课程论文辅导Cancel reply