Cognitive Psychology

Cognitive Psychology Dr Jacqui McKechnie

Memory Information Processing Model Sensory registration • stores for 1 - 2 seconds • different modes related to senses Short term or working memory • stores for 20 - 30 secs approx • capacity 7 ± 2 chunks of info Long term memory • capacity unlimited • can last for a lifetime

Three types of memory are stored Episodic memory Semantic memory Procedural / skills memory Retrieval Decay - unused memories fade with time (Thorndyke, 1914) Interference - more likely to occur with similar events Declarative Memory

Retrieval Failure Tip of Tongue State Improving Memory rehearsal levels of processing encoding-specificity principle

Perception of Sensation Perception is the process through which sensations are interpreted, using knowledge and understanding of the world. It is an active process and people fill in missing information and draw on past experiences to give meaning to what they see hear or touch.

Bottom-up processing - feature detection simple features processed dark/light edges or curves or corners Then structured into larger units until a ‘recognisable’ object is perceived.

Selfridge’s Pandemonium model

Hubel and Wiesel (1979) Cortical neurones respond to bar shaped stimuli which have a specific orientation.

Hubel and Wiesel suggested that simple cells respond to lines or bars, complex cells to larger areas of the visual field and hypercomplex cells respond to size. Livingstone and Hubel (1988) have discovered cells which respond to colour, contrast and texture.

Top-down processing / perceptual hypothesis Perceptions are hypotheses which are tested against sensory data in the same way that experimental hypotheses are tested against data.

Aoccdrnig to a rscheacehr at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Amzanig huh?

Parallel Distributed Processing or Connectionist Models Combine top-down and bottom-up processing. Takes into account both the physiology and the influence of individual experience as relevant factors in perception.

Perceptual Organisation "the whole is greater than the sum of the parts" (Wertheimer, 1925) Gestalt Psychology Figure / ground

Perceptual constancy size, shape, brightness Depth perception relative size, occlusion height in visual field, reduced clarity, shadows Proximity Similarity Continuity Closure Texture Simplicity

Developmental Factors visual cliff studies Crawling babies will not cross over onto deep side (Gibson and Walk, 1960). Babies too young to crawl: show changes in heartrate, but no anxiety show depth perception Campos et al (1970) 2 – 4 months old: begin to perceive patterns, objects and depth

Perceptual Set A predisposition to perceive certain features in the environment rather than others. Factors Affecting Perceptual Set Context Emotion Motivation Cultural factors Expectations

Attention Directs sensory systems toward certain stimuli to select specific information for further processing. Can be voluntary or involuntary. Characteristics which tend to attract attention are abrupt changes in lighting or colour movement appearance of unusual shapes Stroop Effect

RUN BOAT YANKEE GLASS BOAT GLASS RUN YANKEE GLASS YANKEE RUN BOAT

RED BLUE YELLOW GREEN BLUE GREEN RED YELLOW GREEN YELLOW RED BLUE

Thinking encompasses:- reasoning reflecting day dreaming arguing solving problems All are under conscious control and we are able to consider them internally.

Problem Solving Any action, physical or mental, which a person takes in pursuit of a goal. Problems can be:- well-defined ill-defined Puzzles all relevant information provided to solve the problem ? all relevant information not provided Real life

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Cognitive Psychology