Unit 3 Neurobiology & Communication Higher Human Biology Unit 3 Neurobiology & Communication KEY AREA 2: Perception and Memory

Neurobiology & Communication Learning Intentions KEY AREA 2 – Perception and memory Perception 1) Segregation of objects 2) Perception of distance 3) Recognition Memory 1) Sensory memory 2) Short-term memory (STM) 3) Long-term memory (LTM) 4) Location of memory in the brain

Old or Young Lady? 2a) Perception Perception is the process by which the brain analyses and makes sense out of incoming sensory information Perception allows us to segregate objects from one another and their background, recognise what they are and to judge their distance from us The 3 areas of perception involve: Segregation of objects Perception of distance Recognition Old or Young Lady?

2b) Perception – Segregation of objects 1st stage in visual perception is appreciation of an object’s shape When an object appears to stand out from its background in an obvious manner this perceptual organisation is called “Figure and ground” – what is the figure and what is the background?

2c) Perception – Segregation of objects 2nd stage in visual perceptual organisation involves the brain organising stimuli into coherent patterns e.g. patterns of size, superimposition and relative height in field The brain tends to organise visual stimuli into patterns rather than individual parts

2d) Perception – Judgement of distance Binocular disparity Each eye looks at an object from a slightly different position so a slight difference (disparity) occurs between the images The closer the object, the greater the disparity The 2 images are merged into 1 image in the brain producing a binocular image This image indicates depth and distance more effectively than a monocular image   Take your pen Look out the window Close one eye and place the tip of the pen at a structure e.g. a house Swap eyes that are closed What happens?

2e) Perception – Judgement of distance As distance increases from an object, the object is perceived as getting smaller As distance decreases from an object, the object is perceived as getting bigger As objects become nearer and the viewing angle changes, we don’t believe that the object gets smaller or bigger due to Perceptual Constancy Perceptual Constancy depends upon past experience, stored knowledge and relative size

2f) Perception – Recognition Object recognition is the ability to perceive an object’s physical properties e.g. shape, colour, and texture The importance of shape is more important than colour or texture in recognition During early learning, the objects shape is used to characterise and differentiate it from another object e.g. the shape of a banana compared to an apple Matching perceived shapes When a person perceives a shape, they subconsciously try to match this shape with one of the “visual descriptions” already stored in their brain. If the shape is familiar, it will quickly be matched and the object will be recognised. If unfamiliar, you would not be able to name it, but could say what it was similar to

2g) Perception – Recognition The perceptual set is the tendency of a person to perceive certain aspects of sensory information and ignore others. Perceptual set is affected by where past experience, context or expectation as they influence the way a stimulus is perceived Rat or man? Number or letter Unfamiliar object

2h) Memory Memory involves storage, retention and retrieval of information Memories include past experiences, knowledge and thoughts The brain can capture images of sights, sounds, smells, tactile sensations, and emotions all experiences at one time and retain them as memories Memory involves 3 interacting levels. All information entering the brain passes through: - Level 1 - Sensory Memory(SM) Level 2 - Short Term Memory(STM) Level 3 - Long Term Memory (LTM) or discarded

2i) Memory Memory involves 3 interacting levels

2j) Sensory Memory Level 1 - Sensory memory Stimuli from the environment are continuously being perceived as sensory images by the brain. These impressions are VERY SHORT LIVED (only last for 0.5 seconds for visual images & 2 seconds for auditory images)

2k) Short-term Memory (STM) Short-term memory (STM) only holds a limited amount of information – usually about 7 items at one time (memory span), and the items are only held for a short time. The information is either:- Transferred to Level 3 OR Lost by displacement (pushing out old information by new info) Lost by decay (breakdown of memory trace when neurons are activated)

2l) Short-term Memory(STM) – Serial Position Effect The Serial Position Test 1. Show 20 objects one at a time to an individual 2. Each object is observed for 5 seconds 3. After the last object, the subject has to write down as many of the objects that they can remember, in any order Try the AHS Serial Position Effect Test!

2l) Short-term Memory(STM) – Serial Position Effect The Serial Position Effect Recall is best for items shown at the end of the test, followed by items shown at the start. Items shown in the middle of the test are poorly remembered. This is due to the items at the beginning of the test have been transferred into the LTM, and items at the end are still held in the STM

2m) Short-term Memory(STM) – Rehearsal Rehearsal involves repeating information over and over again in order to help you to memorise This process helps to transfer Short-term memory into Long-term memory and is the most effective method to use for learning Rehearsal is used to help pass your Highers, pass your driving test! Investigation Opportunity Effect of rehearsal on motor memory skills

2n) Short-term Memory(STM) – Chunking Short- term memory can be improved by chunking Chunking is when several units are put together to create one meaningful unit e.g. the numbers 95015 are easier to remember as 01595 (code for Lerwick) as you are already familiar with it! Chunking can improve STM Lists of letters to remember :- Set 1 - ICL, TPT, OML, MVM, EZQ, CPG, UPR, MCA, RPA, Set 2 – HIV, FBI, UFO, BBC, AHS, RIP, USA, VAT, NYC Which set is easier to remember? Why? “Learning is not just remembering! It is about making sense of something!”

2o) (iii) Long-term Memory(LTM) Long-term memory (LTM) is thought to be able to hold an unlimited amount of information Information is constantly being transferred between the STM and the LTM If during STM the item is encoded, then this item will be transferred for storage in the LTM. LTM will then be able to retrieve the item Successful transfer of information from STM to LTM is promoted due to rehearsal, organisation and elaboration of meaning

2p) Long-term Memory(LTM) Organisation Information that is organised into logical categories is more easily transferred from the STM to the LTM Which list is the easiest to remember?

2q) Long-term Memory(LTM) Elaboration: Elaboration involves analysing the meaning of the item to be memorised and taking note of features and properties Encoding: The conversion of one or more nerve impulses into a form that can be received & held by the brain and retrieved later from the STM or LTM Shallow encoding: Information encoded by repetition Example: Names of people in the class Elaborative encoding (deeper encoding) Information encoded by associating it with other information such as a meaning or linking it with previous memories Example: Name of people in class & what they look like

2r) Long-term Memory(LTM) – Retrieval Classification of information in the LTM The LTM stores information in distinct categories e.g. types of fruit, colours, numbers, names of family members Retrieval of items in the LTM LTM contains a vast store of items constantly being revised, reorganised and enlarged and new materials flows in. A search is required to retrieve information from the LTM. The search is aided by contextual cues (a reminder) Contextual cues somehow trigger an impulse through a “memory circuit” A memory whose encoding in the LTM is accompanied by unusual, emotional or dramatic events (e.g. a wedding day) possess powerful contextual cues. These enable the experience to be retrieved and recalled clearly throughout life

2s) Location of memory in the brain Type of Memory Possible location Function Episodic Many regions of Cerebral cortex Recall of personal facts, experiences & events Semantic Recall of general knowledge, non-personal facts, ideas Procedural Motor region of cerebral cortex Memories needed to perform motor skills (e.g. swimming) & mental skills (e.g. reading) Emotional Limbic system & cerebral cortex Memories formed as a result of positive or negative associations Spatial Limbic System Memories about environment and spatial orientation (e.g. location of kitchen sink)

Neurobiology & Communication Questions KEY AREA 2 – Perception and memory Testing Your Knowledge Page 234 Q’s 1-4 Testing Your Knowledge Page 246 Q’s 1-5 What You Should Know Page 246 Q’s 1-15 Quick Quiz