PSYC20007 Lecture 2: Lecture 2 - Recognition & Memory
14 Jun 2018
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Lecture 2 - Tuesday 1 August 2017
PSYC20007 - COGNITIVE PSYCHOLOGY
LECTURE 2
RECOGNITION & MEMORY
TODAY
•All of my lectures are tied together by a set of general ideas which have been distilled from the
empirical evidence into a set of basic principles which can be used to understand how cognition
operates.
•The core idea is that our existing knowledge (or prior knowledge) influences what we learning
and how we learn. For instance, in any situation, I draw on my prior experience to interpret the
sensory information the environment provides. Certainly, that sensory information provides a clue
as to what knowledge is useful, but my knowledge guides how I experience the situation (in most
but not all situations). Because of the influence of knowledge on attention, I don’t perceive all of
the details; instead I focus on what seems to be important or salient and allow my knowledge to
fill-in the rest.
•Today’s lecture is about how this knowledge influences recognition memory both in a beneficial
manner and in a detrimental manner. Next week’s lecture is about the representation of the
knowledge itself
•And in my last lecture, I’ll discuss more generally the ideas of learning, how our knowledge guides
our attention, and how we use our knowledge to form explanations of our experiences.
•I like to start with an example to provide a question that we can use the lecture to understand.
WWII: 19 November 1941
•Somewhere off the coast of Western Australia
•I want to begin today’s lecture again by taking you back to WWII roughly two years after the
German invasion of Poland and about 20 days before the Japanese bombing of Pearl Harbour.
•Pictured here is the HMAS Sydney in Sydney Harbour in February 1941. Built 1933 on Britain's
Tyneside and purchased a year later by the Australian navy for use as a light cruiser. Length 171
metres, maximum width 17 metres, displacement 7200 tons, maximum speed 33 knots (61 kph).
Sides are camouflaged with broad stripes first applied in 1940. When war began in 1939, HMAS
Sydney was sent to the Mediterranean and achieved outstanding success. It became the navy's best
and most famous ship.
•On December 23rd 1940, the Kormoran left Germany and sailed to the Indian Ocean, sinking
eleven merchant ships along the way. (HMAS = His Majesty's Australian Ship. HSK =
Hilfskreuzer or auxiliary cruiser.)
TIMELINE
•Sydney was tasked with escorting the troop ship Zealandia for some of its journey to Singapore
but was relieved by the HMAS Durban at Sunda Strait which separates the Indonesian islands of
Sumatra and Java
•Sydney was en route from Sunda Strait to Fremantle when contact was made with Kormoran,
which was disguised as a merchant ship. Sydney followed and gradually closed in on Kormoran,
challenging the vessel continuously using her signal lamp, while closing the distance between the
two ships. At the time, merchant vessels were known to be slow to respond to signaling, and the
Germans exploited this knowledge.
•At 1800 hrs, to further the deception, Kormoran broadcast a QQQQ ‘suspicious ship’ message,
feigning a cry for help in the name of Straat Malakka. By 1815 hrs ,Sydney was less than a mile
distant from the Kormoran. Both ships were steering west-south-west at about 14 knots.
Signaling with flags and flashing light, the Sydney asked ‘Where bound’. The Kormoran replied,
‘Batavia’. The crucial moment came!
when Sydney hoisted a two flag signal bearing the letters ‘IK’, the two centre letters of Straat
Malakka’s four-letter secret identification signal. The Germans could not interpret, so signaling in
plain language the Sydney asked ‘Show your secret sign’. With concealment of his vessel's true !
Lecture 2 - Tuesday 1 August 2017
PSYC20007 - COGNITIVE PSYCHOLOGY
!
identity no longer possible, and with
the advantage of surprise, Detmers
ordered the Dutch !
colours to be struck, hoisted the
German naval ensign and opened
fire with all armament at
approximately 1830 hrs.
•All of the Kormoran’s armament
was brought to bear on Sydney,
concentrating on her bridge, torpedo
tubes and anti-aircraft batteries.
With a second round of fire, Sydney
hit the Kormoran’s funnel and
engine room whilst further artillery
went over the ship. The Kormoran
fired two torpedoes, one striking under Sydney’s turrets and the other passing close ahead of the
ship. The Sydney, crippled and on fire, steamed slowly to the south returning sporadic fire, still
receiving steady hits from the Kormoran. Until approximately 2300 hrs, all that was seen was a
distant glare then occasional flickering until midnight, when all trace of the Sydney disappeared.
KORMORAN SURVIVORS
•The survivor’s accounts were elicited after an interval of 7-21 days; They were mostly working in
their domains of expertise (e.g., navigation)
•The information they provided was critical to their survival
•Some of them were likely to have known the position; others were not
•So where was the Sydney? The accounts of the Kormoran survivors didn’t match up
•And the Sydney couldn’t be found
•Most Australians concluded that the Germans must be lying, and that their conflicting accounts
were part of a ploy to throw the Australians off the scent.
•When Sydney ship hunters went out looking for the boat — and many did — they either
completely disregarded the accounts from the Germans, or, in a couple of cases, focused
exclusively on the captain's version of the story.
•Until very recently, the location of the Sydney was a complete mystery
TODAY
•Fundamental Nature of Memory
•Memory representations are only as good as the input
•Memory is reconstructive
•Expectations can be manipulated
•Memory is context-dependent
•HMAS Sydney: Were they lying?
THE NATURE OF MEMORY
•“Memory, like all other cognitive processes, is inherently constructive. Information from encoding
and cues from retrieval...are all exploited to construct a response to a cue.”
•-- Surprenant & Neath (2009; Principles of Memory)
Lecture 2 - Tuesday 1 August 2017
PSYC20007 - COGNITIVE PSYCHOLOGY
STANDARD MODEL OF MEMORY
•He is interested in the interaction between STM
and LTM.
•Memory is only as good as the details
which are encoded
MEMORY IS ONLY AS GOOD AS THE
DETAILS ENCODED
•Sensory limitations prevent all of the
details of a scene or an event from being
registered in memory.
•Attentional bottleneck limits the amount of information
that is perceived (Recall Philip’s lectures)
•For something like line-ups, our memory can only ever be
as good as the perceptual input.
DISTANCE AFFECTS PERCEPTION
•Distance affects perception (which in turn affects memory)
•On 10 October 1997, a group of young men committed several acts of mayhem in Fairbanks,
Alaska. Their rampage, which culminated in the murder of a teenage boy, eventually resulted in
the arrests of four suspects, two of whom were tried for the crimes.
•The centerpiece of the case for the prosecution was the testimony of Arlo Olson who, while
drunk, had seen the perpetrators at night
and from a distance of 450 ft. Despite these
perceptual disadvantages, Mr Olson picked
the defendants from photographic lineups.
•The face on the right shows you what is
lost when viewing at 450 ft; can you guess
the mystery celebrity?
•The visual system spatially filters what it
sees – it removes details. The size of the
removed details is directly proportional to
the distance of the face from the witness.
•The faces on the left are scaled to mimic
what it would be like to view the same face
from 43 ft and 172 ft. The two figures in
the middle have been blown up to give you
a sense of what is lost by distance.
•The visual system spatially removes details
(in proportion to distance)
•Screenshot on the right is an example of the details lost when looking
at someone from 450 feet (about 150m).
•The way the visual system operates is that it filters information not
only from the periphery but also proportional to distance.
DISTRACTIONS IMPAIRS ENCODING
•Distraction impairs encoding (which impairs memory).
•The amount of interference increases the longer you have to wait
before recall.
DISTINCTIVE FEATURES ATTRACT ATTENTION
•Distinctive Features attract attention (and are Remembered Better)
•Faces which are dissimilar to prototypical or average faces are easier
to remember. -- Light, Kayra-Stuart & Hollander (1979)
Document Summary
For instance, in any situation, i draw on my prior experience to interpret the sensory information the environment provides. Certainly, that sensory information provides a clue as to what knowledge is useful, but my knowledge guides how i experience the situation (in most but not all situations). Wwii: 19 november 1941: somewhere off the coast of western australia, i want to begin today"s lecture again by taking you back to wwii roughly two years after the. German invasion of poland and about 20 days before the japanese bombing of pearl harbour: pictured here is the hmas sydney in sydney harbour in february 1941. Tyneside and purchased a year later by the australian navy for use as a light cruiser. Length 171 metres, maximum width 17 metres, displacement 7200 tons, maximum speed 33 knots (61 kph). Sides are camouflaged with broad stripes first applied in 1940. Sydney was sent to the mediterranean and achieved outstanding success.
