By Judith Rafferty, adapted by Marc Chao and Muhamad Alif Bin Ibrahim

Critical thinkers, educators, decision-makers, and anyone engaging in problem-solving must often handle complex issues and process multiple pieces of information simultaneously. This involves recalling past events, integrating new information, and making sense of it all. These tasks rely on various types of memory, including sensory memory, short-term memory, and long-term memory.

To begin, you might enjoy this video from CrashCourse [9:55], which provides a fun introduction to the topic of memory.

We will now explore how these different types of memory work.

Sensory Memory

Sensory memory is the initial stage of memory processing, where information from our environment is briefly stored before fading away or being passed along for further processing. This type of memory acts as a buffer, holding sensory input for a very short time, typically just a few seconds or less (Gluck et al., 2020). Sensory memory is crucial for helping us navigate the constant stream of stimuli around us, acting as a bridge between perception and cognition. It allows the brain to decide which information is relevant and worth processing further.

Sensory memory can be divided into several types based on the kind of sensory input being processed.

1. Iconic memory: Iconic memory is associated with visual input, allowing us to retain a fleeting image of what we see for less than a second. For instance, when you close your eyes after briefly looking at a bright light, the residual image you “see” is an example of iconic memory.
2. Echoic memory: Echoic memory processes auditory input, retains sounds for about three to four seconds. This explains why you can recall the last few words someone said even if you were not fully paying attention.
3. Haptic memory: Haptic memory relates to tactile sensations, retaining the immediate sense of touch, such as the texture or pressure you feel when running your hand over a surface.

As shown in Figure 4.4.1, attention plays a vital role in sensory memory, determining which sensory inputs move to short-term memory for further processing. Sensory memory holds information for such a brief period that only the stimuli we actively focus on are transferred for further use. This process acts as a filter, helping us manage the vast amount of sensory information we encounter at any given moment. For example, while walking down a busy street, sensory memory registers all the sights, sounds, and smells around you. However, your attention may focus only on the sound of an approaching car or someone waving at you, allowing those specific stimuli to move into short-term memory.

The connection between sensory memory and attention highlights the interconnected nature of cognitive processes. Attention serves as a bridge between perception and memory, determining what sensory input is relevant and worth further processing. For example, perception helps identify and interpret sensory input, such as recognising the sound of a honking car as a potential hazard. Attention then ensures this critical input is passed to memory systems, enabling appropriate action, such as stepping aside to avoid the car.

Short-Term Memory

Short-term memory, also known as working memory, is a critical component of our cognitive system that allows us to temporarily store and manipulate information needed for immediate tasks. It plays an essential role in managing processes like rehearsal, encoding, decision-making, and retrieval strategies, serving as a mental workspace where information is actively held and used. Unlike sensory memory, which lasts only a few seconds, short-term memory can hold information for a slightly longer duration, usually 15 to 30 seconds, before it either fades or is transferred to long-term memory.

Capacity of Short-Term Memory

Research on short-term memory capacity often references the digit-span test, a method in which participants are asked to recall sequences of numbers. This test has revealed that short-term memory typically holds between five to nine items at a time. This capacity aligns with George Miller’s famous concept of the “magical number 7”, which suggests that the average person can focus on about seven items simultaneously. However, individual differences and specific tasks can influence this capacity. Factors such as fatigue, stress, or distractions may reduce how much information short-term memory can effectively manage at any given time.

Strategies for Retaining Information

Short-term memory employs several strategies to retain information, including coding and chunking:

• Coding is the process of representing information in a specific form, such as auditory or visual.
  • Auditory coding involves recalling sounds, such as a melody, the tone of a loved one’s voice, or the rhythm of speech. For instance, when you repeat a phone number aloud to remember it, you are using auditory coding.
  • Visual coding entails recalling images or visual details, like the appearance of a person’s face or the arrangement of furniture in a room. This type of coding is particularly useful for tasks requiring spatial awareness or visual recognition.
• Chunking is a method of organising smaller units of information into larger, more meaningful groups. This strategy helps reduce cognitive load and maximise memory capacity.
  • For example, instead of remembering the sequence 1, 9, 7, 9, you might group it as 1979, a year that holds personal or historical significance. Similarly, when trying to memorise a shopping list, grouping items into categories (e.g., fruits, vegetables, and dairy) can make them easier to recall.
  • Another effective chunking technique involves creating a narrative. For instance, if you need to remember a list of random words, constructing a short story that incorporates those words can significantly improve retention.

The Importance of Chunking in Critical Thinking

Chunking is not just a memory aid; it is a powerful tool for critical thinking. By organising complex information into manageable chunks, individuals can better retain and process ideas, making it easier to analyse situations, solve problems, and draw logical conclusions.

For example, educators often use chunking to present lessons in structured segments, allowing students to grasp intricate concepts step by step. Similarly, decision-makers and problem-solvers use chunking to break down complex scenarios into smaller, interconnected parts, enabling them to approach challenges methodically and with clarity. This ability to organise and prioritise information is essential for crafting strategies, forming well-reasoned arguments, and making sound decisions.

Baddeley’s Working Memory Model

To better understand how working memory operates, Alan Baddeley developed the working memory model, which divides working memory into several interconnected components. Figure 4.4.2 shows how these components manage different types of information and work together to process and store it. Initially, Baddeley identified three main components, and a fourth, the episodic buffer, was added 25 years later to expand the model:

1. Phonological loop: This component handles verbal and auditory information, such as spoken words or sounds.
2. Visuospatial sketchpad: This component manages visual and spatial information, such as images or the layout of a room.
3. Central executive: Often described as the “manager” of working memory, the central executive oversees information processing. It updates and reorganises memory to balance multiple tasks and switches attention between activities.
4. Episodic buffer: Added later, the episodic buffer provides temporary integration of information from the phonological loop, visuospatial sketchpad, and long-term memory. It is controlled by the central executive and serves as a bridge between working memory and long-term memory, facilitating the transfer of information.

To better understand these components, watch this video on working memory by Practical Psychology [7:48]:

As explained in the video, each component of working memory has a limited capacity and operates largely independently. For instance, the visuospatial sketchpad is not affected by the phonological loop, allowing the brain to process visual and auditory information simultaneously without interference.

This model provides practical insights for tasks requiring significant cognitive processing. For example, in situations that involve analysing multiple complex ideas or perspectives, presenting information in different formats can help reduce cognitive load. If verbal explanations overwhelm the phonological loop, visual aids such as diagrams, charts, or illustrations can engage the visuospatial sketchpad instead. For instance, when discussing abstract concepts or exploring interconnected ideas in critical thinking, a teacher might use a whiteboard to visually map out relationships between ideas, helping students process and retain the information more effectively.

The working memory model also sheds light on how information moves into long-term memory. This process involves three key stages:

• Encoding: The initial step of memorising information, such as a phone number.
• Storing: Maintaining the memory over time, often by rehearsing or repeating the information.
• Retrieval: Accessing the stored information when it is needed, such as recalling the phone number.

Long-Term Memory

To wrap up our exploration of memory, let us take a closer look at long-term memory, with a particular focus on the phenomenon of priming. As shown in Figure 4.4.3, long-term memory can be broadly categorised into two types: explicit memory and implicit memory (Goldstein, 2019; Gluck et al., 2020).

Explicit memory, also known as declarative memory, includes two subcategories:

1. Semantic memory involves the memory of facts and general knowledge.
2. Episodic memory is the memory of personal experiences.

Explicit memory is characterised by awareness. It refers to memories that a person can consciously recall and articulate. For instance, remembering the capital of a country or recalling a family vacation are examples of explicit memory. As Gluck et al. (2020) explain, explicit memory “consists of memory of which a person is aware; you know that you know the information” (p. 280).

On the other hand, implicit memory involves memory that operates without conscious awareness. This type of memory includes skills, habits, and processes that are automatically recalled without intentional effort. For example, riding a bike or typing on a keyboard often draws on implicit memory. According to Gluck et al. (2020), implicit memory is defined as “memory that occurs without the learner’s awareness” (p. 280).

Priming is a phenomenon associated with implicit memory and operates unconsciously (Goldstein, 2019). Priming occurs when exposure to one stimulus influences how we respond to a subsequent, related stimulus without our conscious awareness. For example, if you recently read an article about critical thinking, you might be more likely to recognise or recall words like “analysis” or “reasoning” more quickly when encountered later.

Priming

Priming is a psychological phenomenon where exposure to a stimulus influences how we respond to subsequent stimuli and shapes how we perceive and interpret new information. Gluck et al. (2020) define priming as “a phenomenon in which prior exposure to a stimulus can improve the ability to recognise that stimulus later” (p. 88). Similarly, Kassin et al. (2020) explain it as “the tendency for frequently or recently used concepts to come to mind easily and influence the way we interpret new information” (p. 118). Essentially, priming makes certain concepts or ideas feel familiar, even if we are not consciously aware of having encountered them.

For instance, research has demonstrated that when we are subtly exposed to specific words or images, we are more likely to later recognise or choose something related to those stimuli (Gluck et al., 2020; Goldstein, 2019; Kassin et al., 2020). For example, if you are shown words related to “logic” or “analysis” in a subliminal manner, you may be more inclined to approach a problem with a critical thinking mindset.

The Impact of Priming on Social Behaviour

Priming can influence social behaviour by subtly shaping how people act, often without their awareness. This is particularly true when the stimulus is presented subconsciously (Kassin et al., 2020). The impact of priming on behaviour has been demonstrated in various studies, including a notable experiment by Bargh, Chen, and Burrows (1996).

In the first experiment of their study, participants were primed with words associated with either “rudeness” or “politeness”. Afterwards, they were placed in a situation where they needed to decide whether to interrupt an experimenter to ask for information. The results showed that participants primed with concepts of rudeness interrupted the experimenter more quickly and frequently than those primed with polite-related stimuli. This demonstrates how subtle cues can influence behaviour in ways consistent with the primed concepts.

In the second experiment, participants were primed with words associated with elderly stereotypes. After the priming, participants who had been exposed to these stereotype-related words walked more slowly down a hallway when leaving the experiment compared to those in the control group. Their behaviour aligned with the traits stereotypically associated with the elderly, showing how priming can subtly alter physical actions based on unconscious associations.

These findings highlight how priming affects not only perceptions but also behaviours in ways that often go unnoticed by the individuals involved. To explore a similar study on the behavioural effects of priming, watch this video by Dcreyethink for further insights [5:12]:

How Priming Can Affect Perception

If you watched the Crash Course video Perceiving is Believing, you may recall an example where viewers were primed to see either a rabbit or a duck based on the framing of a question (“bird or mammal”). This illustrates how priming influences perception, especially when the information presented is ambiguous. In such cases, we are more likely to rely on top-down processing than bottom-up processing to make sense of the stimulus.

Bottom-up processing begins with sensory receptors, which gather raw information from the environment and send signals to the brain. The brain processes these signals and constructs a perception based on the data. However, when stimuli are ambiguous, the brain often relies on top-down processing, where prior knowledge, experiences, and expectations shape how we interpret incoming information. This type of processing, frequently described as concept- or schema-driven, allows us to make sense of ambiguous stimuli by filling in gaps using mental frameworks.

Priming enhances top-down processing because it makes certain concepts or associations more readily available. When we have recently or frequently encountered specific ideas, they come to mind more easily and influence how we interpret new, unclear information. For example, Kendra Cherry, in her article Priming in Psychology, discusses how the Yanny/Laurel viral phenomenon of 2018 demonstrated this effect. The priming effect influenced whether people heard “Yanny” or “Laurel” when confronted with the ambiguous auditory clip.

In the context of visual perception, Feldman Barrett (2017) explains how priming can significantly shape how we interpret others’ emotions. She notes that facial expressions are often more ambiguous than we might assume, making them particularly susceptible to the influence of priming. For instance, if we are told a person in a photograph is screaming in anger, we are more likely to perceive anger in their expression, even if this interpretation is inaccurate.

The individual might actually be expressing joy, such as celebrating a significant accomplishment like winning a tennis match. In such a case, the facial expression could reflect a mix of positive emotions. However, when primed to expect anger, our perception narrows, leading us to misinterpret the emotions. Providing contextual information, such as the situation surrounding the facial expression, can help us interpret ambiguous stimuli more accurately.

This example highlights how priming shapes our reliance on prior knowledge to make sense of ambiguous information, emphasising the importance of being mindful of how external cues and context influence our perceptions. Developing awareness of these influences is essential for enhancing critical thinking, as it helps us evaluate situations more objectively and accurately.

References

Bargh, J. A., Chen, M., & Burrows, L. (1996). Automaticity of social behavior: Direct effects of trait construct and stereotype activation on action. Journal of Personality and Social Psychology, 71(2), 230-244. https://doi.org/10.1037/0022-3514.71.2.230

Feldman Barrett, L. (2017). How emotions are made: The secret life of the brain. Pan Macmillan.

Gluck, M. A., Mercado, E., & Myers, C. E. (2020). Learning and memory: From brain to behaviour (4th ed.). Macmillan International.

Goldstein, E. B. (2019). Cognitive psychology. Cengage.

Kassin, S., Fein, S., Markus, H. R., McBain, K. A., & Williams, L. (2020). Social psychology (2nd Australian and New Zealand ed). Cengage Learning.