고려대학교 정보경영공학과 IMS 621 Engineering Psychology Chapter 3. Attention OVERVIEW Selective attention (cognitive tunneling) Pay attention to multiple things

고려대학교 정보경영공학과

IMS 621 Engineering Psychology

Chapter 3. Attention

OVERVIEW Selective attention (cognitive tunneling)

Pay attention to multiple things in sequence – intentional but unwise choice Focused attention

Pay attention to 1 thing – tendency to be distracted by external environmental info. Divided attention

Pay attention to multiple things at the same time simultaneously- limited ability to time sharing performance

SELECTIVE ATTENTION Visual Sampling

eye and visual sampling seek information and searches for targets Visual scanning behavior (attentional searchlight) Eye fixation system

Fovea area perceives detail: about 2°of visual angle



Pursuit movement – the eye follows the target Saccadic movement

discrete, jerky from one stationary in the visual field to next Sometimes superimposed on pursuit movement Saccade – suppresses visual input Fixation – display info. processed during fixation

Location – center of the fixation Useful field of view – diameter around the central location which info. is extracted Dwell time – how long the eye remains at that location

Supervisory control context scans the display of a complex system under supervision allocates attention through visual fixations to various instruments the target is known

Target search context scans a region of the visual world a target’s location and existence is unknown



Supervisory Control Sampling Optimality of Selective Attention

stimulus environment -- channels and critical events1. Mental model guides sampling

form a mental model of the statistical properties of events – frequency and correlations2. Adjustment to event rate – sluggish beta

the sampling rate is not adjusted with event frequency3. Sampling affected by arrangement – more likely to make horizontal scans than diagonal scans –

simplifying rules and heuristics4. Memory imperfect; sampling imperfect – sampling remainder5. Preview helps – as the number of channels increases, fail to take advantage of preview6. Processing strategies – cognitive tunneling

failed system, delayed feedback Eye Movement in Target Search

Environmental Expectancies fixate most on areas of containing the most information (Yarbus, 1967) a scan path over same picture dependent upon seeking info. (Yarbus, 1967)

Display Factors and Salience neither consistent pattern of display scanning nor optimal scan pattern in search



certain display factors to the allocation of visual attention salience and abrupt stimulus onset in the visual periphery – may bias decision making presence of unique stimuli (singletons) – slowed the detection of other targets physical location in the display – the upper left, concentrated on the center (edge effect) dominated by conceptually or knowledge-driven scan strategies

Display-Driven and Conceptually driven processing they commonly interact – standardization of roadway and sign design positive guidance – forecast the unexpected event

Search Coverage and the Useful Field of View the highest acuity region of fovea – an angel of no more than 2 degrees UFOV – a circular area around the fixation point -- 1 to 4 degrees of visual angle

size – determined by the density of information & the discriminability of the target aging – restricted UFOV training enlarge UFOV, benefits are equal across age groups reduction in UFOV has serious implication such as driving UFOV is sensitive to task demand in the foveal region

Fixation Dwells survey dwells – short, used to establish the regions more likely to contain a target examination dwells – used to provide a detailed examination of the region for an embedded target



difficulty of information extraction low familiarity, low frequency, and out of context – higher information content (longer dwells) expertise

Visual Search Models How long to find a target? What is the probability in a given period of time? Drury’s Model (1975, 1982)

1st stage – target search stage the probability of locating a target increases with more search time (fig. 3.2) – diminishing rate

2nd Stage – decision stage uses the expectancy of flaws to set a decision criterion

Variables affecting search speed (fig 3.3)1. the number of elements to be searched – serial search (50 msec/item)2. exceptions to serial search – one level along one salient dimension

greater search efficiency for parallel than serial preattentive (requiring few attentional resources) for parallel and attentive for serial

3. serial search – the target is difficult to discriminate from distractors4. exceptions to serial search – the presence of features rather than absent

different discriminabilities of targets in the two situations



5. dispersion of targets -- scanning distance and visual clutter trade off6. any of several different target types slower than only one

exception – a single common feature7. extensive training – automaticity parallel search (consistent mapping not varied mapping)

Structured Search Basics information that may help guide the search is available Application: Menus target items are reached in the minimum average time (fig 3.4) linear visual search model – frequently searched items positioned toward the top of the menu optimal number of items per menu is between three and ten (Lee and MacGregor, 1985) criterion-based model (Pierce, Sisson, and Parkinson, 1992)

the effect of similarity in menu search Directing Attention

advise an operator in advance where attention should be directed more accurate as the stimulus-onset asynchrony between the warning (cue) and the target

increases – SOA=200ms more effective than SOA=50ms peripheral cues (out of foveal area) – more effective with short SOAs, a transient effect, stimulus-

driven, automatic process central cues – more effective with longer SOAs, long lasting, goal-directed, controlled

interpretation



PARALLEL PROCESSING AND DIVIDED ATTENTION Preattentive Processing and Perceptual Organization

visual processing of a multiple-element world – two main phases preattentive phase (STSS, automatic, grouping) and attentive phase (perception,

selecting) Gestalt psychologists (fig 3.5) – items to be preattentively grouped together on the display --

proximity, similarity, common fate, good continuation, closure high redundancy all items of an organized display must be processed together to reveal the organization

(parallel processing) -- global or holistic processing single object within the display -- local processing (fig 3.6) -- response conflict – global

precedence emergent features – global property of a set of stimuli (displays) (fig 3.8) global processing tends to be preattentive and automatic -- reduce attentional demands

Gestalt principles – produce groupings or emergent features spatial proximity of different elements compatible with task demands

Spatial Proximity Overlapping Views: The Head-Up Display although spatial proximity will allow parallel processing, it certainly will not guarantee it

Neisser and Becklin (1975) – separation defined not only in terms of differences in visual or retinal location but also in terms of the nature of the perceived activity

Wickens and Long (1995) – an unexpected obstacle was detected more poorly with the HUD than with the head-down configuration -- HUD could improve control of position during landing, both in view and when the runway was obscured by clouds



the HUD appears to facilitate parallel processing of scene and symbology when the pilot expects the stimulus and interferes when the stimulus is quite unexpected

conformal nature of the symbology Visual Confusion, Conflict, and Focused Attention spatial proximity – confusion

1. spatial density little effect on visual search time2. Wickens and Andre (1990) -- critical variable in predicting performance is the degree of

spatial separation of relevant item from irrelevant, not the spatial separation between the relevant items themselves

3. Holahan, Culler, and Wilcox (1978) – to locate and respond to a stop sign in a cluttered display is directly inhibited by the proximity of other irrelevant signs in the UFOV

4. Eriksen and Eriksen (1974) -- perceptual competition – a failure of focused attention caused by the competition (ex. UHP)

response conflict (ex. FHF), redundant gain (ex. HHH) Object-Based Proximity different attributes of a single stimulus object at one spatial location

concurrent processing of elements lying close together in space (space-based model of attention)

concurrent processing occurs when elements lie within a single object (object-based model) Stroop task – subject is asked to report the color of a series of stimuli as rapidly as possible

multiple dimensions belonging to s single object are likely to be processed in parallel integral dimensions produce a cost for a filtering task and a benefit with redundant

dimensions



Applications of Object-Based Processing in cognitive psychology, an object has three features

1. surrounding contours or connectedness between parts2. rigidity of motion of the part3. familiarity

benefits of objects in two contexts1. conformal symbology – mapping of display objects to real-world objects2. object displays – multiple information sources are encoded as the stimulus

dimensions of a single object Conformal Symbology and Augmented Reality conformal symbology helped the pilot divide attention between the display and the world

beyond, align the display object to the real object, and reduce tracking error Object Displays parallel processing of object features to create multidimensional object displays (fig 3.10)

The Proximity Compatibility Principle three ways in which multiple display channels can be integrated: emergent features,

spatial proximity, object integration proximity-compatibility principle – whether different tasks are served differently by more or

less integrated displays to the extent that information sources must be integrated, there will be a benefit to

presenting those sources either close together, in an object-like format, or by configuring them to create emergent features



to the extent that information sources must be treated separately, the benefit of the high-proximity object display will be reduced, if not sometimes reversed

close proximity increases the possibility of parallel processing close proximity and objectness can create useful emergent feature that help information

integration if they correspond to the key variables of the task emergent features can hurt performance if they are not mapped into the task response conflict can result if proximity combines variables that require focused attention Color Coding benefits

1. rapid localization2. capitalizes on population stereotypes3. tie together spatially separated display elements4. redundancy in combination with shape, size, or location

limitations1. failure of absolute judgment – five or six colors, glare or low illumination (affected by

ambient light)2. no ordered continuum – brightness (saturation) rather than hue3. population stereotype – poor design with a conflict meaning4. irrelevant color coding can be distracting -- display-cognitive compatibility



ATTENTION IN THE AUDITORY MODALITY omnidirectional – no analog to visual scanning as an index of selective attention transient

Auditory Divided Attention an unattended channel of auditory input remains in preattentive STAS (3 – 6 sec) attention switch

on – examined off – LTM (preattentive) – pertinent enough focused attention

negative priming -- information presented in an unattended channel is temporarily inhibited for several seconds following presentation – slower

auditory object as a sound with several dimensions -- parallel processing Focusing Auditory Attention

monaural and dichotic listening – large benefits of dichotic over monaural listening in filtering out the unwanted channel

cocktail party effect – auditory selective attention (pitch, intensity, semantic properties) auditory attention can be directed by “cueing”

Cross-Modality Attention parallel inputs across modalities redundancy gain -- speeds up processing dividing attention between modalities may be better than dividing attention within a

modality visual dominance over auditory and proprioceptive















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고려대학교 정보경영공학과 IMS 621 Engineering Psychology Chapter 3. Attention OVERVIEW Selective attention (cognitive tunneling) Pay attention to multiple things