Cognition: Human understanding of their environment (thoughts)

Perception: Human experience their environment (senses)

Window: A channel to collect information-sensory and processing system.

Central scientific approach: acquisition, processing, storage, recall of data in the human brain

• iterative comparison of sensory input with internal (stored) knowledge

• representation: cortical processing and mapping • illusions: inherent misrepresent of physical world • active sensing: intelligent search system strategies

'We don’t just see features - we automatically put them together into meaningful parts of the scene' We do this effortlessly.

Detection and recognition: Deciding something is there and then drawing on our memory to recognise what it is.

Grouping: he brain has some automatic rules for deciding how to organize features:
what goes together to form an object

Luminance boundary: in regions of equal luminance excitation and inhibition cancel each other
at the boundary excitation and inhibition are not balanced and thus increase the relative difference of perceived brightness

Shape & Shading: o recognize an object we have to have an idea of its 3D shape
Shading is very important to do this Texture/depth

Important part of our communication with each other - evolutionary context

Face detection: The first step of the process has to be the detection of a face, which requires extracting the features that all faces have in common

This could be achieved by simple “template matching”

We have a tendency to see faces everywhere, one of the most common examples of Pareidolia, to make meaning
where there is none

Neurones in STS responded to facial motion, posture, and eye gaze

Neurons in inferior temporal cortex more likely to respond on the basis of identity

Photofit theory (Penry & Ryan, 1971)
Photographed features to allow subject to build a face.

Composite face effect: Composite faces interfered with recognition of a half face – the effect disappeared upside down. The holistic processing obliges us to combine information automatically.

Thatcher illusion: In the upside down faces we appear to process the features separately and don’t see the strange relationship between them. The holistic processing in the upright faces makes the unusual arrangement instantly salient.

Eye tracker (main method): This involves a small camera focused on the eye and software that tracks where the pupil moves. By calibrating the pupil position against fixed points on the screen one can work out where the participant is looking.

Using this kind of technology we can build a picture over time of where a participant was looking.

We can measure: dwell time (each fixation), frequency of fixation, total duration of fixations (total looking time), order of fixation positions.

A central part called the fovea has a high density of photoreceptors.

In order to have a detailed representation of a part of the image the light from that part needs to land in the fovea.

The brain needs to know which part of the motion on the retina is caused by eye movements and which part is caused by something moving in the scene.

• This can be done by cancelling out the signal using an “efference copy” from eye muscles.

• Also, cues from the scene, such as whole image motion can be cancelled out.

Combining motor and visual systems: Brain areas involved in eye movements are active both when visual information is being processed and when eye movements are being made. These are important “cross-modal” areas.

Theories on Eye movements: Active vision emphasises the role of eye movements linked with attention in real-life tasks.

ATTENTION is a crucial element of information processing in the human brain/mind

It sits in the middle of a bottom-up processing from perception to memory, top-down feedback loop.

Orientating (directing) attention: Invalid cue : increase response time, error rate.

Valid cue : decrease response time, error rate. cueing enhances attention, improves decision.

Neuralpsychology- hemi spatial neglect: attentional deficit one half of the visual scene is simply ignored.

Often caused by stroke, typically interrupting blood flow to right parietal lobe – critical in attention and some brain scan of patient suffering from left hemifield neglect.

Affects eating, dressing, reading, navigation, line bisection, cancellation, copying etc.

Saccades: We move our eyes approximately 3 times per second > saccadic, suppression.

Changes to a scene that are made during blinks and saccades are difficult to spot.

Eye blinks: Each time we blink our eyes the visual scene is disrupted.

Missing change in natural scenes: W e can miss large changes evereyday: inattentional blindness. "The door study"

• misdirection : diverting peoples’ attention away from an important event

• memory distortions: false memory altering spectators’ recollection of an event • perceptual distortions e.g. visual illusions

Sounds signal events > alarm system emotional balance: listening to music, screeching
communication.

Amplitude and frequency (1/period, measured in Hz = cycles per second).

Harmonic intervals are determined by characteristic frequency ratio.

Harmonics: Frequency & amplitude of pure tones > perceived pitch and loudness. Musical tones are combinations of pure tones : fundamental (determines pitch) + harmonic frequencies (determine timbre)

Equal loudness contours are determined by matching the perceived intensity of tone pairs at various base intensities

Noise exposure can lead to temporary threshold shifts (auditory fatigue) and permanent (partial) deafness.

Tinnitus: continuous humming or ringing >> leads to suppression.

Presbycusis: selective high- frequency hearing loss with age (ongoing).

Systems used in speech processing: Heard word-Auditory analysis system-->Auditory Input Lexicon--> Semantic system.
Speech- Phoneme Response Buffer-->Spoken Word Lexicon--> Semantic System.

Binaural unmasking : spatial distance and difference in frequency support separation < difference between ears.

High-level effects (attention, familiarity of voice, language) & sensory fusion.

Masking: the detection of a tone is impaired if another tone or noise is presented at the same time
masking depends on proximity in space and similarity in frequency composition.

Perception involves memory: Recognition = sensation + prior knowledge.

Memory allows us to plan and do things in the absence of sensation.

Maintenance rehearsal:repeating items over and over to maintain them in short-term memory.

Elaborative rehearsal: An encoding strategy to facilitate the formation of memory by linking new information to what one already knows.

Perceptual and comprehension processes leave behind a memory trace.

Important thing to study is not the inherent properties of memory systems, but rather the nature of encoding processes.

memory systems, but rather the nature of encoding processes

Presented a list of words, Each word could be associated with one of three types of encoding. Imagine one of the words was MEAL...

3. Semantic: Does the word fit in this sentence: “the man ate his _” ? (Yes)

Which of the following cues will be more effective for recalling the word PIANO? – 1)somethingmelodious?,or

Iconic memory: Holds visual input for 250 msec.
Representation is pre-categorical (literal record of percept)

Primacy: Primacy gradient – First few items can be rehearsed a lot and so more likely to move into long-term memory.

Recency gradient: Last few items of the list are still in STM when you start to write the list down.

Explicit memory: when retrieval of a memory is deliberate/requires conscious recollection. Also called declarative memory

Implicit memory:Implicitmemory–whenbehaviour/performance indicates that memories are being retrieved in the absence of a deliberate, conscious, attempt to retrieve them, e.g.,

Retrograde: a loss of memory-access to events that occurred or information that was learned in the past.

Anterograde amnesia: A loss of the ability to create new memories after the event that caused amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact.

Frontal lobes [working memory (central executive); source monitoring; prospective memory].

HM: operated on in the 1950s to bilaterally remove the medial temporal lobes (about 2/3 of the hippocampus). Following surgery, his epilepsy was greatly improved. Personality was unchanged. IQ went up. However.... Unable to encode/retrieve new episodic memories. HM had developed severe anterograde amnesia.

Temporal gradient in retrograde amnesia: Temporal gradient may be due to slow-scale consolidation processes => earlier memories have had longer to be consolidated.

Triggers include severe stress, depressed mood ,history of transient organic amnesia (Kihlstrom & Schacter, 1995).