Set 2: Problem Solving, Attention and The Senses

Well-defined problem

All problem aspects are clearly specified and it is clear when a goal has been reached

Ill-defined problem

Problem aspects are not clearly specified from the starts, and the end and constraints are unclear

Knowledge-rich problem

Can only be solved by those who have a lot of specific or relvant knowledge

Knowledge-lean problem

Most of the information needed is contained in the problem statement

What type of problems are most used in research?

Well-defined and knowledge-lean

Reproductive thinking (non-insight solutions)

Uses systematic reuse of previous experiences, with problems solved incrementally

Productive thinking (insight solutions)

Involves a novel restructuring of the problem, and is more complex

Insight

A sudden relaisation that often breaks an impasse or mental block and is believed to depend on a degree of unconscious mental processing

Representational Change Theory

Form mental representation of the problem, repeatedly try to solve it, reach an impasse, restructure the problem representation (constraint relaxation, re-encoding, elaboration)

Mental set

The ability to use previously successful strategies to solve problems. Sometimes this involved continuing to use previously successful problem-solving strategies whn it is innapropriate or sub-optimal.

Functional fixedness

A mistaken assumption that an object only has a limited number of familiar uses. Children show less bias towards functional fixedness.

Heuristics

Processes by which humans use cognitive shortcuts to arrive at decisions quicker and easier - ‘rules of thumb’ that often produce a reasonable answer.

Hill-climbing heuristic

Changing the current state to one that seems closer to the goal. Used when problems are too big to understand, so the solver can ocus on short-term goals.

Means-end analysis

Instead of moving closer to the end goal, break down the task and move closer to a subgoal. This analysis is commonly used in AI.

Cognitive bias

Systematic error resulting from the use of heuristics.

Gambler’s fallacy

Tendency to think that future probabilities are altered by past eventsA

Anchoring bias

Tendency to over rely on one piece of information

Action bias

Tendency to act even when inaction would be better

Analogy

A comparison between two objects, or systems of objects, that highlights respects in which they are thought to be similar.

Raven’s progressive matrices

A test that requires participants to compare images in a 3×3 grid, identify a pattern across a grid and solve for the missing image. Measures fluid intelligence and is successful at predicting performance in other tests of ability.

Superficial similarity

Solution-irrelevant details are common to the two problems

Structural similarity

Casual relations across some of the main components are shared

Procedural similarity

Procedures for turning the solution principle into concrete operations are shared

What type of problem is analogous problem solving most useful for?

Superficially dissimilar problems

Urbanski et al. (2016) - Analogous problem solving and neuroscience

Tested patients with focal damage in the frontal lobes and found that lrPFC lesions are associated with reduced analogous problem solving

Hobeika et al. (2016) - Anologous problem solving and cognitive neuroscience

Performed a meta-analysis revealing that left rostrolateral prefrontal cortex was one of the regions most consistently activated across analogical reasoning studies

Expertise

A very high level of thinking and performance in a domain because of many years of deliberate practice

Long-term working memory

Experts can hold far more in working memory than models would predict, and expertise involves the ability to rapidly store and retrieve large amounts of relevant information

Template theory

Chess players have a template, or an abstract structure of the board, which has Core (fixed informations) and Slots (variable information) and each template codes ~10 locations on the chess board.

Brain plasticity

Changes in the structure and function of the brain that affect behaviour and are related to experience or training.

Umwelt

The subset of the world than an organism can detect and that is meaningful to it

Transduction

The transformation of the energy of a stimulus into a change in the electric potential on the membrane of the receptor cell

What makes up the sensory signal pathway?

Receptors —> thalamus —> primary sensory cortex —> secondary sensory cortex —> association cortex

Bottom-up perception

Constructed from sensory input, information is passed on to higher levels of the system for more complex processing

Top-down perception

Interpretation of sensory input is influence by context and knowledge presented in higher cognitice systems

What is the receptor for audition

Organ of corti —> made up of basilar membrane, tectorial membrane and hair cells.
Hair cells in the basilar membrane are bent as they rub against the tectoral membrane, and mechanical energy is transduced into neural activity.

Tonotopic

Frequency

Helmholtz’s Place theory (1857)

Suggests tonotopic organisation of the basilar membrane and most other auditory system components. Different frequencies cause peak displacement at different locations.

Anatomical coding

The point of maximum displacement of the wave differing accoding to frequency - perception of sound depends on the place each frequency vibrates along the basilar membrane

What is a limitation of Helmholtz’s place theory (1857)?

Explains hearing for higher frequencies but struggles to explain low frequencies.

Rinne (1865) & Rutherford’s (1880) Frequency theory

Suggests the activity of the auditory nerve matches the frequency of the sound, which is known as temporal coding.

Limitation of Rinne (1865) and Rutherford’s (1880) frequency theory

Works to explain low frequencies, but not high as the neural refractory period is too slow.

Auditory signal pathway

Ipsilateral cochlear nuclei —> superior olives —> lateral lemniscus —> inferior colliculi —> medial geniculate nuclei of the thalamus —> primary auditory cortex

Primary auditory cortex

Temporal lobe —> tonotopically organised

Secondary auditory cortex

A ‘belt’ surrounding the primary auditory cortex region, referred to as parabelt areas

Anterior pathway association area of auditory cortex

Projects to frontal cortex and identifies sound

Posterior pathway association area of auditory cortex

Projects to parietal cortex, located the sound in space and prepares for action

Electromagnetic spectrum

Visible light

Receptors for sight

The lens concentrates the light to the fovea on the retina. Light hights the pigment epithelium within the retina, and the reflected light is detected by photoreceptors, which can be split into rods and cones.

Rods

~125 million in retina, highly sensitive to light, responsible for vision in dim lighting

Cones

~6 million in retina, fovea contains only cones, responsible for colour vision. 3 types of cones responsible for 3 colours:
- L-cones (red)
- M-cones (green)
- S-cones (blue)

Visual transduction

Horizontal and amacrine cells integrate signal coming from multiple photoreceptors. Ganglion cells reviece integrated information from multiple photoreceptors covering a patch of the retina, known as the receptive field.

Receptive fields

On-centre ganglion cells, off-centre ganglion cells

Visual signal pathway

signals from left and right visual field seperated in optic chasm —> lateral geniculate nucleus —> primary visual cortex

Visual cortex

Organized heirarchically - lower areas process basic information (orientation, shape) and higher areas process more complex stimuli (faces, objects). V1, V2, V3, V3a, V4, V5

Dorsal stream association pathway of vision

Sensitive to spatial locations, active during spatial attention tasks

Ventral stream association pathway of vision

Sensitive to visual features such as colour and shape

Receptors for somatosensation

Mechanoreceptors (pressure), Thermoreceptors (temperature), Nociceptors (pain)

Transduction for mechanoreceptors

Merkels disks - reponds to light touch

Pacinian corpuscle - responds to deep pressure

Ruffini’s endings - responds to skin stretch

Transduction for thermoreceptors

Free nerve endings, close to the surface, respond to heat and cold

Transduction for nociceptors

Strong pressure, strong heat/cold, chemical, polymodal

Somatosensory signal pathway

Nerves relay sensations from a particular region of skin —> contralateral hemisphere via two pathways —> primary somatosensory cortex

Dorsal-column medial-lemiscus system

Mainly fine touch and proprioception

Anterolateral system

Mainly processes pain and temperature

Primary somatosensory cortex

Located on the posterior side of the central sulcus, topographically organised from the medial to the lateral.

Cortical plasticity

Cortical space can be functionally remapped by input from neighbouring regions, meaning the brain rearranges connections to make use of all the neurons

Secondary somatosensory cortex

Object recognition, textures, shapes and sizes as well as connecting the S1 to areas of the brain responsible for actions

Posterior parietal association cortex

Integrates somatosensory information with other information, for example motor components.

Circumvallate

Inverted V on rear of tongue, circular mound-like structures surrounded by a trench

Foliate

Folds of tissue lateral to circumvallate papillae, where tongue attaches to mouth

Fungiform

Mushroom-shaped on edge of tongue. ~6 taste buds per papillae buried in the surface

Receptor cells for gustation

Each tastebud contains multiple receptor cells. Food particles bind to microvilli and the cells transform chemical signals into electrical signals sent to the brain via cranial nerves.

Gustation signal pathway

Receptor cells —> cranial nerves —> Thalamus —> Insular cortex —> Orbitofrontal cortex

Salt

Sodium ions enter the cell via epithelial sodium channels leading to depolarisation

Sour

Acidic substances release protons which enter cells, or are blocked from leading cells, causing depolarisation

Bitter

Bitter substaces bind to molecules on receptor cells

Sweet

Sugars bind to molecules on receptor cells

Umami

Umami substances bind to molecules on receptor cells

Spice

Not considered a ‘taste’ and is transduced by pain receptors

Analytical modality

Humans find it easier to identify individual smells rather than a blend

Olfaction transduction

odorants in air —> olfactory epithelium through nose (orthonasal olfaction) or the mouth (retronasal olfaction) —> olfactory bulb

Olfactory receptors

350 in humans. Receptors of the same type project to the same areas (glomerulus). When enough receptors detect the same molecule, the mitral cell depolarises and sends the signal to the brain.

Olfactory signal pathway

Olfactory bulb (mitral cells) —> Amydala & hypothalamus/Hippocampus & entorhinal cortex/Frontal cortex

What is different about the olfactory sensory pathway?

It does NOT route through the thalamus

Attention

Ability to select behaviourally relevant input and ignore the rest

Exogenous attention

Involuntary, stimulus driven, caused by external sensory input

Endogenous attention

Voluntary, goal-driven, controlled by internal thoughts

Spatial attention

Often described as a ‘spotlight’ that enhances information at a specific location in the visual field

Feature-based attention

Enhances the representation of low-level features such as colour, motion, orientation

Object-based attention

Attention selects a coherent object, rather than just a chunk of space

Focused attention

One target

Divided attention

Multiple targets

Overt attention

With eye-movement

Covert attention

Without eye-movement

Selective attention

Filtering through necessary informationS

Sustained attention

Prolonged focus

Top-down attention

Selective attention, goal-directed, driven by internal priorities, expectations and task demands

Bottom-up attention

Information that catches attention, stimulus-driven by salient or unexpected features in the environment.

How do top-down and bottom-up attention work together?

In a continuous and parallel manner, allowing us to focus on what is necessary while also scanning the environment for what may be important

Cherry’s Cocktail Party (1953)

Used a dichotic listening task, where the voices’ features were manipulated. It was found the more different the physical characteristics of the voices, the easier the tasl was, and that unattended information is filtered out very early in sensory processing