History and Study of Memory

• Notes from January 15, 2025

Historical Context

• Aristotle (384-322 BCE) examined perception, memory, and mental imagery.
• Wundt and Titchener (1870s) established psychology as a distinct field, focusing on conscious mental events using introspection.
• Behaviorism, prominent in the early 20th century, studied how behavior changes with stimuli.

Advantages and Disadvantages of Behaviorism

• Advantages include being systematic and objective, utilizing learning history.
• Disadvantages include failing to explain everything and attributing behavior to only external stimuli, ignoring the "mental" cause.
• Different stimuli may produce the same or different responses.
• Kant emphasized that not all events are observable, necessitating reasoning backwards.

Studying Memory

• Subvocal speech involves reading in the mind to maintain information in working memory.
• Lab tasks include reaction time (RT), error rate, and recall.
• Eye tracking and mouse tracking are used to monitor the location of attention.
• Lab settings allow for the control of extraneous variables and manipulation of variables, but may lack ecological validity.
• Case studies aid in understanding how typical processes are disrupted, often due to injury, damage, or congenital differences, such as in the case of Phineas Gage.

Neuroimaging Techniques

• Neuroimaging techniques include event-related potentials, PET scans, and fMRI.
• Neurons receive transmitters via dendrites.
• Sodium (Na+) channels open, while potassium (K+) leaves.
• Synapses are spaces between neurons.
• At rest the measurement is -70 mV.
• Depolarization occurs when it is less negative which leads to action potential.

Object Recognition

• Early word recognition experiments used tachistoscopes to present visual stimuli (words) for a controlled duration, followed by a post-stimulus mask.
• Bottom-up processing is data-driven, starting with stimuli.
• Visual cortex cells fire at a high rate when exposed to specific stimuli, and the firing pattern is interpreted to assemble features.
• Focusing on features allows concentration on commonalities, and the same feature combination can lead to different object recognitions.
• Words can be recognized even when presented briefly (30-40 milliseconds) due to word frequency and repetition.
• Top-down processing is concept-driven, starting with knowledge and expectations.
• The word superiority effect shows better letter recognition in a word context compared to individual letters, predicted by word-formedness.

Feature Nets and Word Recognition

• Feature detectors connect to letter pairs and words in a neural network.
• Specific activation levels increase with input.
• When a detector reaches a specific response threshold level it will fire.

Word Recognition

• Toward Frequency efret
• Repitition priming
• Response to ambiguous stimuli

Recognition Errors

• Inefficiency of bigram detectors can cause errors due to bias toward certain letter combinations.
• Over-regularization occurs.

Feed Forward/Feedback

• Feature networks not only activate detectors at high levels (feed forward), but higher-level detectors also provide feedback to lower-level detectors (inhibit firing, deactivate)
• McClelland & Rumelhart model: Any detector at any level can activate or inhibit other detectors.
• Feature nets extend to objects, enabling object recognition by components (RBC) using basic features called geons (geometric ions) like cubes, cylinders, etc.
• Objects can be recognized from nearly any angle (viewpoint independent) and when partially occluded.

Face Recognition Characteristics

• Highly specialized and dependent on viewpoint.
• Inverted faces decrease recognition substantially.
• Face recognition relies on a holistic view.
• Combining the top half of one face with the bottom half of another can cause difficulty in recognition (composite effect).

Attention

• Concentration of mental activity which involves a limited portion of info from memory.
• Involved in nearly every cognitive process
• Attention is often unconsciously activated, utilizing both bottom-up and top-down processing.
• Selective attention is the ability to focus on one stimulus while "tuning out" others, tested through dichotic listening tasks.

What People Notice and Ignore

• People notice a change in voice, tone change, gender of voice, volume/pitch, their name (cocktail party effect), and words of high significance.
• People do not notice actual words, switches to gibberish, or different language.

Attention

• Explanations include blocking unwanted input and promoting desired information.
• Inattentional blindness involves not "seeing" a stimulus in a visual field, occurring in daily life with potentially devastating effects, less likely in individuals with ADHD.
• Change blindness occurs when failing to detect a change in a scene, due to attention being a limited resource, tested using the "flicker paradigm".
• It is easier to detect a change that is a central part of the scene or involves quick motion.

Theories

• Limited perception or limited memory.
• Late selection occurs at 80ms and early
• Unattended stimuli can influence perception (priming), receiving processing but being blocked from consciousness or memory. Evoked potentials show processing even for unattended stimuli.

Selective Attention

• Selective attention can be primed via repetition (stimulus-based) or expectations (expectation-based).
• Indicators can cue detectors.
• Posner and Snyder (1975) measured response time to stimuli pairs, which can be neutral, primed, or misled, with varied validity.
• Low validity conditions showed the misled condition being slower than natural.

Attentional Blink

• Attentional blink occurs at 200-500ms
• Second simulus must be 1200ms apart to be simultaneously detected.
• Attention can be viewed as acting like a spotlight, whatever is in the "beam" receives extra processing, moving even before eyes do.
• Directing is based on needs or intentions.
• Directing also based on prominent features, predictability/unexpected things, and cultural gender.
• Eye tracking reveals attention focus and different brain sites show movement of attention within three systems: orienting, alerting, and executive.
• Neglect syndrome supports the idea of space-based attention, as damage to the right parietal lobe impairs object sighting in the left field of vision.

Feature Binding

• Feature binding is how the separate features from any object are bound together for recognition of the whole object.
• A binding problem occurs when multiple features are parallel processed separately
• Attention bind properties/features together (possible binding errors).
• Combined search requires much more attention while feature search require little attention/effort.

Divided Attention

• When you attempt to do two or more stimuli/tasks simultaneously.
• Divided attention depends on the specificity of resources by which the most successful is when tasks require different resources.
• Difficulty or slower processing is experienced when the same resources are being used.
• Diff. resources are not always better for dividing attention
• Ex: driving+talking.
• The initiator of any responses to stimuli, that contains a metal tool is named the Response selector.
• The main character that controls divided attention is the Executive control.

Executive Control Functions

• Set goals/priorities
• Choose strategies
• Direct functioning ac cognitive processes
• Relies on past experiences
• Goal Maintenance
• Inhibits aviomatic responses Llaves export)
• Damage to prefrontal cortex disrupts executive control: perseveration error and Goal neglect