Cognitive Revision Notes

Extraneous variables are factors that may have an unwanted effect on the dependent variable, potentially influencing the results and making it appear as though the independent variable is having an effect when it is not.

Sensory memory acts as a filter for environmental information received through the senses. If information is relevant and we pay attention to it, it can enter short-term memory (STM). If not attended to, it decays rapidly.

STM has a capacity of 5 to 9 items and a duration of up to 30 seconds. Information is mainly encoded acoustically, and rehearsal can help transfer it to long-term memory (LTM).

Rehearsal, particularly elaborative rehearsal, helps transfer information from STM to LTM. Maintenance rehearsal, such as repeating information, can keep it in STM temporarily.

LTM has an unlimited capacity and can last from minutes to a lifetime. Information is mainly encoded semantically, meaning it is based on its meaning.

Laboratory experiments showing primacy and recency effects provide evidence for separate stores. Participants recall more words from the beginning (primacy effect) and end (recency effect) of a list, indicating different processing in STM and LTM.

The multi-store model's description of STM may be too simplistic, as dual task experiments show that performance varies based on the type of tasks, suggesting a more complex structure like the Working Memory model may be more accurate.

The central executive (CE) is an attentional process that supervises and allocates tasks to slave subsystems. It focuses, divides, and switches attention, monitors incoming data, makes decisions, and has a very limited processing capacity without storing information.

A confounding variable is an extraneous variable that influences the dependent variable, confounding the results of the study and making it difficult to measure the true effect of the independent variable on the dependent variable.

Using monozygotic twins (identical twins) in a matched pairs design provides researchers with a very close match for participant variables, which enhances the validity of the study by controlling for genetic and environmental factors.

The phonological loop is subdivided into:

1. Articulatory process: Allows maintenance rehearsal by repeating sounds or words to keep them in the phonological store, with a capacity of about two seconds.
2. Phonological store: Temporarily stores auditory information, preserving the order of information as it arrives.

The visuospatial sketchpad temporarily stores visual and/or spatial information, allowing individuals to hold a visual map of their route when following directions. It has a limited capacity of about three or four objects and is subdivided into:

• Visual cache: Briefly stores visual data (e.g., images).
• Inner scribe: Records the arrangement of objects in the visual field, helping to rehearse visual/spatial information.

The episodic buffer, added in 2000, is a temporary store that integrates acoustic, visual, and spatial information from other subsystems. It maintains a sense of time sequencing and has a limited capacity of about four chunks. It combines information from subsystems with long-term memory and links to wider cognitive processes, such as perception.

Evidence from case studies, such as KF reported by Shallice and Warrington (1974), supports the existence of separate subsystems. KF had a digit span of one, indicating impairment in his phonological store, while his visual memory remained intact, suggesting distinct verbal and visuospatial systems.

A weakness of the model is the difficulty in specifying the precise functioning of the central executive. For example, in the case study by Elsinger and Damasio (1985), a man with brain damage showed good reasoning and high IQ but poor decision-making, suggesting that the central executive may not be a single system as expected.

Tulving proposed that long-term memory can be divided into episodic memory (remembered experiences) and semantic memory (remembered facts).

Episodic memory is linked to the time in which events occurred, allowing recall of specific experiences with temporal context. In contrast, semantic memory is detached from any temporal link, allowing recall of information without reference to when it was learned.

Input into episodic memory is continuous, as it captures experiences over a period of time within a specific time-frame. Semantic memory, however, is input in a fragmented way, where factual information is learned at different times and later pieced together.

Episodic memory retrieval is context-dependent, meaning the context aids in recalling the memory. Semantic memory retrieval is not context-dependent; it relies on inferences and logical thought, remaining unchanged regardless of the context of learning.

Evidence from brain-damaged patients, such as KF, supports Tulving's idea of separate stores in long-term memory. KF could not recall personal events (episodic) but could recall factual information (semantic).

The cases of HM and Clive Wearing demonstrate a weakness of Tulving's model, as both were unable to recall long-term memories from episodic storage but could remember how to perform tasks, suggesting the existence of a further long-term store for procedural memory.

In 1985, Tulving suggested the existence of a separate procedural memory store, which contains memory for skills and abilities, such as learning grammar or riding a bike, in addition to episodic and semantic memory.

A schema is an organized package of information that stores our knowledge about the world, made up of all our previous experiences and expectations about an event.

The three main transformations observed were:

1. Confabulation: Details added or changed to align with cultural expectations.
2. Levelling: Omission of information deemed unimportant, leading to shorter retellings.
3. Rationalisation: Changes made to parts of the story that seemed irrational, including the order of events.

Bartlett's study showed that participants altered the story to fit their cultural expectations, leading to confabulation, levelling, and rationalisation, which indicated that memory recall is influenced by existing schemas.

Bartlett's findings have influenced the legal system by demonstrating that eyewitnesses are unreliable, as they recall what they expect to see rather than what they actually observed, leading to convictions no longer being based solely on eyewitness testimony.

Wynn and Logie's study suggested that Bartlett may be incorrect in claiming that memory is reconstructed and distorted upon each recall, as they found only a small reduction in recalled information from familiar real-life situations, indicating that such memories may be less susceptible to schema influence.

Processing speed varies among individuals and is influenced by their short-term memory (STM) capacity. Younger children typically have a shorter digit span than older children, indicating that memory capacity increases with age.

Schemas, as suggested by Bartlett, are influenced by individual experiences and can guide the reconstructive nature of memory. For example, a child may perceive an object differently based on their schema, affecting how the object is remembered.

Bartlett's War of the Ghosts Study showed that experiences and culture influence schemas, which in turn affect how memories are encoded and retrieved. For instance, British participants altered elements of a Native American folk tale to fit their own cultural schemas.

Palombo's study found that individuals with high or low scores in episodic memory also scored correspondingly high or low in semantic memory, indicating that people tend to have overall 'good' or 'poor' memories. Additionally, men scored higher in spatial memory.

Sebastian and Hernandez-Gil found that digit span increases with age, with the youngest group (5 years) having a mean digit span of 3.76, which increased to 5.28 by age 11. The study also noted that Spanish children had a lower digit span compared to English children, likely due to the word length effect associated with longer Spanish digit words.

To investigate whether LTM and STM have the same acoustic encoding system, particularly focusing on the influence of acoustic and semantic similarity on long-term memory for word sequences.

Correct recall of acoustically similar words was worse than dissimilar words during initial learning, but this did not significantly affect long-term memory recall. Participants found semantically similar words more difficult to learn and recalled significantly fewer semantically similar words in the retest.

Unlike STM, LTM appears to rely on semantic encoding. The retest recall of semantically similar words was impaired compared to other lists, suggesting that encoding in long-term memory is largely semantic.

The use of non-naturalistic stimulus materials led to a lack of ecological validity, as the word lists used do not reflect how people typically remember information in real life.

The aim was to investigate the development of the phonological loop component of working memory using verbal digit span as a measure of loop capacity.

The independent variable was the year of schooling (and year group) of the participants.

The study found a clear increase in digit span with age, with the youngest group (5 years) having a significantly lower average digit span compared to older age groups, peaking at 11 years before stabilizing up to 17 years.

The average digit span was lower for Spanish children compared to English children.

A strength was the use of several standardised procedures, ensuring consistency in how the study was conducted across participants.

The study lacks mundane realism as digit sequence recall is considered artificial and has limited task validity, as children are unlikely to learn random sequences of numbers in their daily lives.

The two types of extraneous variables are situational variables and participant variables.

1. Manipulation of the IV: The Independent Variable (IV) is directly manipulated by the researcher to produce a change in the Dependent Variable (DV).
2. Randomisation: Participants are randomly allocated to conditions (independent design) or take part in each condition (repeated design).
3. Control: Efforts are made to control extraneous variables that may affect the IV other than the DV, allowing researchers to identify cause and effect relationships.

A strength of using lab experiments in cognitive psychology is that the standardised procedures allow for easy comparison of results. For example, in Baddeley (1996b), controlling the rate at which words were presented (one every three seconds) enables replication in different settings, leading to a more reliable understanding of memory processes.

A weakness of using lab experiments in cognitive psychology is the difficulty in generalising findings to real-life situations. For instance, results from studies like Peterson and Peterson (1959) may have limited application to actual memory situations, such as revising for exams, leading to concerns about ecological validity.

The Independent Variable (IV) is the element that is manipulated or changed by the researcher in the experimental group. The Dependent Variable (DV) is the element that is measured by the researcher as a result of the changes in the IV; it is dependent on the IV group.

Operationalisation of variables refers to how researchers intend to measure or test the variables in a study in a precise way. It ensures that variables like the IV and DV are defined clearly to allow for objective measurement and replication of the study, enhancing reliability and validity.

The two types of hypotheses are:

1. Null Hypothesis: States that the IV will have no effect on the DV (i.e., nothing will happen).
2. Experimental Hypothesis: States that the IV will have an effect on the DV.

Additionally, hypotheses can be classified as Directional (one-tailed) predicting the nature of the outcome, or Non-Directional (two-tailed) which does not specify the direction of the results.

An independent measures design is when different participants are used in each condition of the experiment. The group receiving the experimental treatment is called the experimental group, while the group that does not receive the treatment is known as the control group.

The repeated measures design allows for control of individual differences between participants, as the same participants are used in each condition. This means that any differences observed can be attributed to the experimental treatment rather than individual variability.

In a repeated measures design, order effects may occur, which can confound results. These effects can be negative, such as fatigue or boredom, or positive, such as learning or practice effects from participating in multiple conditions.

A matched pairs design involves using different participants who are matched for important characteristics (e.g., age, gender, IQ) relevant to the study. Matching is done before the study begins to ensure that the groups are comparable on these characteristics.

Achieving matched pairs can be difficult and time-consuming. It requires reliable and valid procedures for pre-testing participants to identify matches, and complete matching on all variables affecting performance is rarely achievable.

In a repeated measures design, order effects can be controlled through counterbalancing. This method helps to mitigate the impact of fatigue or practice effects by varying the order in which participants experience conditions.

In an independent groups design, it is crucial that participants are randomly allocated to different conditions to ensure that any differences observed are due to the experimental treatment rather than pre-existing differences between participants.

Situational variables are factors connected with the research situation, such as temperature, instructions, time of day, lighting, and materials. They are controlled through standardization to ensure that only the independent variable differs between conditions.

Participant variables are characteristics of individual participants that may affect findings, such as age, intelligence, motivation, and experience. These variables can influence performance in a study, independent of the independent variable.

Gender can act as an extraneous variable in some circumstances, as males and females may differ psychologically due to socialization. For example, research suggests women may be more obedient than men. However, it is not always relevant, such as in memory experiments where no significant differences are noted.

Demand characteristics occur when participants try to make sense of the research situation and act accordingly, which can include guessing the purpose of the research, acting nervously, or displaying social desirability bias.

Investigator effects arise from the behavior and characteristics of researchers, which can influence the results of an investigation. For example, expectation effects may occur when a researcher is biased towards a specific outcome, leading to misinterpretation of ambiguous behaviors. Additionally, in observational studies, the presence of the observer can alter participants' natural behaviors. Characteristics such as age, gender, and communication style of the investigator can also affect responses in interviews or questionnaires, potentially leading participants to provide desired answers.

To control situational variables, researchers can implement standardised procedures and instructions to ensure that all participants are tested under the same conditions. This helps to minimize variability that could affect the results of the study.

Participant variables can be controlled through experimental design techniques such as:

1. Matched pairs design: Participants in one condition are matched with similar participants in another condition based on characteristics like intelligence or age.
2. Random assignment: Randomly assigning participants to different conditions helps reduce bias and ensures that participant characteristics are evenly distributed across groups.

A single blind procedure is a method where participants are unaware of the hypothesis and do not know which condition they are assigned to. This helps to reduce demand characteristics, as participants cannot alter their behavior based on their knowledge of the study's aims.

A double blind procedure is a research method where neither the participants nor the research assistants know the hypothesis or the condition that participants are in. This is important because it minimizes both investigator effects and demand characteristics, ensuring that the data collected is unbiased and reliable. A research assistant typically carries out data collection to maintain this blinding.

Reliability refers to the consistency of measurements or observations of the same psychological event across different instances. It indicates that findings can be trusted to occur repeatedly under similar conditions.

Test-retest reliability is a method of assessing reliability by presenting the same participants with the same test or questionnaire on two different occasions, ensuring that findings are consistent over time without feedback after the first presentation.

Internal validity refers to how well a study's procedure establishes a causal relationship between the independent variable (IV) and dependent variable (DV), and whether the results are confounded by extraneous variables.

Construct validity is the extent to which a test measures what it intends to measure, ensuring that the operational definitions used in the study accurately reflect the theoretical concepts being investigated.

External validity is the degree to which the findings of a study can be generalized beyond the specific study context, allowing for the application of results to other situations or populations.

Ecological validity refers to the extent to which research findings can be applied to real-world settings, indicating how well the results explain behavior in different environments or situations.

Objective research involves measurements that lack interpretation or judgment from the researcher, leading to more reliable results. In contrast, subjective research is influenced by the researcher's beliefs or opinions, which can affect the consistency of measurements.

1. Nominal: Discrete categories (e.g., hair color: blonde, brown, red, black).
2. Ordinal: Rankings rather than scores (e.g., attractiveness on a scale of 1-5).
3. Interval: Scores with equal distances between them (e.g., temperature).
4. Ratio: Similar to interval but with a true zero point (e.g., height, weight).

A large standard deviation indicates that there is much variation around the mean, meaning the scores are widely spread out.

A small standard deviation indicates that the data is closely clustered around the mean, suggesting less variability among the scores.

A standard deviation of zero indicates that all data values are the same, meaning there is no variability in the data set.

To investigate the effect of acoustic similarity on short-term memory.

There will be significantly fewer words recalled in serial order from participants given acoustically similar words compared to those given acoustically dissimilar words.

The Mann Whitney test was used because the study looked for a difference between independent groups (acoustically similar and dissimilar words) with interval ratio data.

Mean recall for acoustically similar words was 4, while for acoustically dissimilar words it was 6.

Acoustic similarity does lead to STM confusion preventing accurate recall, indicating that STM processes words acoustically for this effect to occur.

Participants were tested in different environments, which could have introduced extraneous situational variables affecting concentration and recall, thus decreasing the internal validity of the study.

EWT stands for Eyewitness Testimony. It refers to information given by a witness after observing an event or crime, which is recorded in a police statement or provided as verbal testimony in court.

Relying on EWT can lead to inaccurate convictions or allow guilty individuals to escape justice, as jurors may depend heavily on witness testimony, especially in the absence of forensic evidence.

Research indicates that as a witness's stress level increases, their memory accuracy tends to decrease. High stress can lead to a focus on threatening stimuli, like a weapon, which may impair their ability to accurately identify the perpetrator.

Valentine & Mesout (2009) found that higher anxiety levels in witnesses correlated with less accurate recall and a lower likelihood of correctly identifying the culprit, suggesting that EWT may be unreliable under stress.

Yuille & Cutshall (1986) found that witnesses who reported higher levels of arousal were actually more accurate in recalling details of a real incident, challenging the notion that stress always leads to unreliable eyewitness accounts.