Cognition Human Factors PSYC 2220 Michael J Kalsher

Cognition Human Factors PSYC 2220 Michael J. Kalsher Department of Cognitive Science

Human Information Processing System • Perceptual Stage – Bringing information in through senses (sensory memory) for comparison against existing knowledge in (long-term) memory to give it meaning. • Cognitive Stage – Central processing (or thought stage) where we compare the new information with current goals and memories. – Transform the information, make inferences, solve problems, consider responses. • Action Stage – Brain selects a response and then coordinates/sends motor signals for action.

Generic Model for Human Information Processing Note: Assumes a linear progression of processing

Measuring Information Processing • Cognitive psychology (science of the mind) began to replace behaviorism in the late 1950 s. • Modeling “information processing” required the use of special techniques (or dependent variables) to make inferences concerning what is going on “inside the head. ” – Reaction time (simple; choice) – Verbal Protocol analysis (asking people to tell you what they’re thinking before/during/after a task).

Memory: The Atkinson-Shiffren Model Richard Atkinson & Richard Shiffrin, 1968 Sensory Register: where sensory info enters memory Short-term store (WM or STM): receives and holds input from both the sensory register and long-term memory. Long-term store: where info is held indefinitely (levels of processing).

Sensory Memory • Sensory Trace– temporary holding “bin” – Visual trace is termed “Iconic memory” – Auditory trace is termed “Echoic memory” – Presumed to all be present for other sensory modalities • Characteristics – Veridical (accurate) – Large storage capacity – Brief time—decays and/or is interfered with by new incoming information (clears for next input) – Pre-categorical—before the information is interpreted (i. e. , it in a “raw” form)

Iconic & Echoic SM: Some Distinctions • Iconic held for briefer time (less than 1 sec) than echoic (2 -3 sec) • Iconic memory is more spatially oriented • Echoic memory is more temporarily oriented

Sensory Memory: Some Classic Findings • Backward Masking When subjects are presented with a “masking visual stimulus” immediately after a “target visual stimulus” brief (< 50 msec) they fail to consciously perceive the target stimulus. • Suffix Effect A weakening of the recency effect when an irrelevant item is appended to the end of a to-be-learned list of words (Morton, Crowder & Prussin, 1971). Example: When asked to memorize a list, say: 1, 5, 7, 9, 15, people remember the first and last items best. If an additional number (e. g. , 20) is added to the end of the list—but is not part of the to-beremembered information, recall for the last item will be much weaker.

Sensory Memory: Object & Pattern Perception • Perceptual recognition: Process by which sensory elements are transformed into a mental representation or code and then compared with stored information to categorize it. – Involves “Many-to-One” mapping – Perception gives meaning to sensory input by aggregating many simple information “bits” into fewer global representations. • Characteristics of this process: – Perception by feature analysis (bottom-up processing) – Simultaneous top-down & bottom-up processing

Feature Analysis: Bottom-up Processing • Analysis of complex stimuli in terms of the component parts. • A three-stage process – Break pattern into features – Match features to patterns stored in LTM – Decide which stored pattern is the best match

Feature Analysis: Text Perception • Features of letters are compared with features of stored knowledge for the letters for possible matches. – Performed quickly and without awareness for familiar objects (such as letters). • Perception of print usually proceeds hierarchically: – Features combined into letters, letters into words, words into sentences – Exception: words seen frequently tend to be processed holistically, a process termed unitization. • DANGER, WARNING, CAUTION, NOTICE, ABC, CBS, NBC, FOX

Controlled vs. Automatic Processing • Controlled Processing (Bottom-up) – Effortful cognitive processes that require attention to initiate and sustain them. – Used to comprehend relatively unfamiliar or complex information. • Automatic Processing (Top-Down) – Cognitive processes that can be initiated and run with minimal demand on attentional resources. – For task to become automatic, it must exhibit consistent mapping between its cognitively stored elements. – When tasks are combined there will be less cross-interference in time-sharing to the extent that one or both tasks are automated.

Design Implications: Textual Displays • Feature compatibility – Accuracy and speed of recognition will be greatest when the features of a display are in a format compatible with features and units in memory. • Upper and lower case – For isolated words: upper case letters are more recognizable. – In sentences: mixture of upper and lower case print is most easily perceived. • Use print for text displays – Print is more easily recognized and read than cursive writing. • Minimize abbreviations – Full words should be used for displays (ALAC, CCP, CISL, IRB, C&M) – Best abbreviations rule is truncation (use only first few letters of the word). • Space between words or character strings – Ensuring there are gaps between words is crucial for accurate perception. – Make use of “Chunking” (e. g. , arrangement of alphanumeric characters on license plates).

Feature Analysis: Geon Theory Suggests everyday objects are recognized on the basis of combinations of a set of 30 geometric shapes termed geons.

Role of Geons in Object Perception Object recognition proceeds via the following steps: – Objects broken down into component geons. – Each geon categorized on the basis of feature matching. – Objects are identified on the basis of the specific configuration of their component geons.

Important Assumptions (of Biederman’s approach) • Only edges of geons are critical for object recognition. • Color and details may be necessary if subobject shapes for two objects are sufficiently similar that the objects cannot be discriminated on the basis of the component shapes alone.

Assumption #1: Only edges of geons are critical for object recognition.

Assumption #2: Color and detail necessary if sub-object shapes for two objects are sufficiently similar that the objects cannot be discriminated on the basis of the component shapes alone. Basketball vs. an Orange

Design Implications: Line drawings vs. photographs/pictures

Representing the human figure in safety symbols The human figure is frequently the main component in a safety symbol. In other safety symbols, a part of the human figure—a hand, foot, or other body part—makes up the main element of the symbol. In either case, representation of the human form must be simple, consistent, and believable. Interpretation must be instant and must not require the viewer to study the symbol to determine what part of the body is involved or in what way a hazard exists.

The Role of Context in Perception • Higher level concepts or information are sometimes needed to process “low level” perceptual features when stimuli are unclear or incomplete. • Use of top-down processing occurs simultaneously and automatically along with bottom-up processing. Perceiving a “ 6” or a “b” is determined by context

Top-Down Processing • More critical for speech recognition than reading printed words because of the “fleeting” nature of speech (i. e. , , speech decays whereas print remains) • Verbal context around critical spoken words greatly facilitates recognition. – In a study of recognition of warnings among pilots, the verbal warning “Your fuel is low” was more comprehensible than “fuel low” (Simpson, 1976).

Information Processing Trade-offs • When stimulus quality is high, bottom-up processing will predominate. • As stimulus quality degrades, increased contextual information and redundancy is needed (top-down) to keep recognition levels high.

Display Guidelines: Text Displays & Icons • Optimize Bottom-up Processing – Optimize factors such as size and contrast and quality of the stimuli. • Optimize Top-Down Processing – Use actual words rather than random text strings – Restrict overall message vocabulary (fewer possibilities = higher efficiency) – Provide contextual cues to aid recognition/comprehension. • Evaluate Tradeoffs – Given limited space, evaluate environment for degraded viewing conditions & availability of contextual cues to determine appropriate trade-off between bottom-up and top-down processing. • Usability Testing – Evaluate recognition & comprehension of icons. – Conduct usability testing using the actual environment and/or elements of the task context.

Pictures and Icons: Important Tradeoffs Advantages: – Universal/Not Language Dependent – Takes advantage of dual-coding (analog spatial image & semantic/meaning) – Useful for many applications (e. g. , highway signs, computer displays, warnings) Potential Disadvantages: – Legibility • May be difficult to discriminate under degraded viewing conditions • Pictorial messages should be distinctive, sharing a minimal number of features with other pictorials. – Comprehension • Standardization and training (e. g. , ANSI; ISO; GHS). • Whenever possible, words should be used with symbols/icons.

The GHS: Respiratory Hazard Explosive Breaking All the Rules? Hazardous to Compressed Gas Aquatic Environment Flammable Health Hazard Oxidizer

The GHS: Considering Alternatives

The GHS: Considering Alternatives

The GHS: Considering Alternatives

The GHS: Considering Alternatives

Working Memory • Term used to describe short-term store of information that is currently active in central processing. • Only a limited amount of information can be brought from sensory register to working memory (1 st bottleneck of the information processing system). • Relatively transient (decays rapidly) and limited in size. • “Work bench” of consciousness in which we compare, evaluate, and transform cognitive representations. • Must be able to accommodate demands while supporting active problem solving operations (e. g. , hold a phone number in memory until we have completed dialing it). • Holds two different types of information – Verbal & Spatial

Brown-Peterson Experiments • Demonstrated that without rehearsal, the ability to recall drops exponentially to an asymptote. • Now-classic experiments conducted to test characteristics and limitations of short-term memory. – One by John Brown in 1958 and another by Lloyd and Margaret Peterson in 1959, hence the term “Brown. Peterson paradigm”. – Tasks used by the researchers were mostly the same and yielded similar results.

• • • Procedure: 24 participants (psychology students) were asked to remember/recall trigrams (meaningless three-consonant syllables, e. g. , TGH). To prevent rehearsal participants counted backwards in threes or fours from a specified random number until they saw a red light appear. Participants recalled trigrams after intervals of 3, 6, 9, 12, 15 or 18 seconds. Findings: The longer the interval delay the less trigrams were recalled. Participants were able to recall 80% of trigrams after a 3 seconds delay. However, after 18 seconds less than 10% of trigrams were recalled correctly. Conclusion: STM has a limited duration when rehearsal is prevented. It is thought that this information is lost via trace decay. Brown, J. (1958). Some tests of the decay theory of immediate memory. The Quarterly Journal of Experimental Psychology, 1012 -21. Peterson, L. , & Peterson, M. (1959). Short-term retention of individual verbal items. Journal of Experimental Psychology, 58(3), 193 -198.

Baddeley’s Working Memory Model Strength of the model lies in its ability to integrate a large number of findings from research on short-term/working memory.

Alan Baddeley’s Model Components – Central Executive: Overall control and regulation of cognitive processes (e. g. , binding information from numerous sources into coherent episodes, coordination of the slave systems, shifting between tasks, selective attention). Not as “Central” as once thought. – Visuospatial sketch pad holds information about what we see. Two components: Visual cache (stores info about form and color) and Inner scribe (deals with spatial and movement information and transfers information to the Central Executive). – Phonological loop deals with auditory information and consists of two parts: a short-term phonological store that is subject to rapid decay, and an articulatory rehearsal component (articulatory loop) that can revive the memory traces (usually sub-vocally). – Episodic Buffer links information across domains to form integrated units of visual, spatial and verbal information with time sequencing (e. g. , memory of a story or movie scene).

Working Memory: Limitations Ability to keep (verbal or spatial) information in working memory is dependent on: – Capacity (how much to-be-remembered information must be kept active) – Time (how long must it be kept active) – Similarity (how similar is the to-be-remembered material to other elements in working memory) – Attention (how much attention is required to keep the to-beremembered material active)

Working Memory: Capacity • Capacity of working memory = 7 +/- 2 “chunks”. • Chunk = unit of working memory space defined jointly by physical and cognitive properties that bind items together. • Physical binding: – 8, 7, 5, 3 = 4 chunks – 23, 27, 35, 46 = 4 chunks • Cognitive binding: – Example: • M T V N B C F B I C I A I Q = 14 chunks • MTV, NBC, FBI, CIA, IQ = 5 chunks

Working Memory: Time • Strength of information in WM decays rapidly unless it’s actively rehearsed (reactivated). • Maintenance rehearsal is essentially a serial process of sub-vocally articulating each item. • The more chunks, the longer it. takes to cycle through items in maintenance rehearsal. • “Half-life” of working memory = the delay after which recall is reduced by one-half. – Half-life of 1 chunk = approx. 70 sec – Half-life of 3 chunks = approx. 7 sec

Working Memory: Confusion and Similarity Which list of letters is most likely to be retrieved from working memory? EGBDVC or ENWRUJ? Items that sound like a to-be-remembered item impair recall more than do items that sound different from it. The memory confusion occurs whether the list is heard or seen.

Working Memory: Attention and Similarity Working memory is resource-limited. – When attentional resources are diverted to another task, rehearsal stops and memory decays. – If the competing activity uses the same resources, disruption will be worse than if it uses different resources • Basis for development of Multiple Resource Theory.

WM: Implications for Design • Minimize working memory load – Items that operators need to retain in working memory during task performance should be kept to a minimum • Provide visual echoes (e. g. , visual presentation of phone numbers) • Exploit chunking – Optimize physical chunk size (i. e. , 3 or 4 numbers or letters) – Use meaningful sequences (letters are more meaningful than numbers) – Keep numbers separate from letters (e. g. , license plate sequencing) • Minimize Confusability – (More confusion when lists sound similar; Use physical distinctions to reduce confusability) • Exploit different working memory codes – Working memory retains 2 qualitatively different types of information: visual spatial and verbal phonetic • Each system processes information somewhat independently • If one code is being used, it will be interrupted more by processing that same type of info than by processing info in alternative code

Long Term Memory LTM is Conceptualized as having 3 basic stages: – Encoding Input of sensory memory, short term memory, and attention – Storage Some memorial representation is laid down – Retrieval Remembering the output (Output probably loops back into short-term memory)

Theories of LTM • Levels of Processing • Paivio’s Dual Code Theory • Tulving’s episodic vs. semantic memory theory

Levels of Processing Memory strength depends on the strength of associations made between to-be-remembered items and existing information in LTM. Deep processing is superior to other more superficial types of processing. Example – Participants in an study employing the incidental memory paradigm in which they are unaware that their memory will be tested later. – They are given one of 3 tasks involving, say—an apple Surface task (Is it red? Is it small? ) Phonological task (Does it rhyme with chapel? ) Semantic task (Is it edible? Is it a Fruit? Is it good for you? ) • People remember the information best when engaged in semantic processing, as opposed to superficial processing.

Paivio’s Dual Code Theory • Based on the fact that our memory for pictures is better than our memory for words. – Words are coded in memory by a verbal code – Pictures are coded visually (by their appearance) and verbally. • Dual coding theory helps explain why concrete words and concepts (chair) are easier to remember than abstract words (honor). – Concrete words/concepts are more easily transformed to a pictorial image than abstract words.

Tulving’s Memory Theory: Types of Memory Episodic – Knowledge of specific experiences as we move about the world. Semantic (Jeopardy knowledge) – Conceptual memory (knowledge of world and how it works) – Devoid of memories of particular instances. Procedural (“Muscle memory”) – Implicit and skill-based knowledge that is usually associated with performing an activity or procedure (e. g. , riding a bicycle).

Episodic Memory • Episodic memory represents our memory of experiences and specific events in time in a serial form, from which we can reconstruct the actual events that took place at any given point in our lives. • It is the memory of autobiographical events (times, places, associated emotions and other contextual knowledge) that can be explicitly stated. Individuals tend to see themselves as actors in these events, and the emotional charge and the entire context surrounding an event is usually part of the memory, not just the bare facts of the event itself.

Semantic Memory • Semantic memory is a more structured record of facts, meanings, concepts and knowledge about the external world that we have acquired. • It refers to general factual knowledge, shared with others and independent of personal experience and of the spatial/temporal context in which it was acquired. Semantic memories may once have had a personal context, but now stand alone as simple knowledge. It includes such things as types of food, capital cities, social customs, functions of objects, vocabulary, understanding of mathematics, etc. Much of semantic memory is abstract and relational and is associated with the meaning of verbal symbols.

Procedural Memory • Procedural memory (“knowing how”) is the unconscious memory of skills and how to do things, particularly the use of objects or movements of the body, such as tying a shoelace, playing a guitar or riding a bike. • Typically acquired through repetition and practice, procedural memory is composed of automatic sensorimotor behaviors that are so deeply embedded that we are usually unaware of them. Once learned, these "body memories" allow us to carry out ordinary motor actions more or less automatically.

Memory and the Brain • The different types of LTM are stored in different regions of the brain and undergo quite different processes. • Declarative memories (episodic and semantic) are encoded by the hippocampus, entorhinal cortex and perirhinal cortex (all within the medial temporal lobe of the brain), but are consolidation and stored in the temporal cortex and elsewhere. • Procedural memories, on the other hand, do not appear to involve the hippocampus at all, and are encoded and stored by the cerebellum, putamen, caudate nucleus and the motor cortex, all of which are involved in motor control.

Long-Term Memory: Basic Mechanisms • Strength – Determined by frequency and recency of use. • Associations – Retrieval of information in LTM dependent on the number and richness of associations with other items. (related to depth of processing) • Forgetting – Exponential function; most forgetting occurs quickly, then reaches an asymptote. – Major reasons for memory retrieval failure: • • Weak strength due to low frequency or recency Weak or few associations with other information Interfering associations Recall vs. Recognition

Information in LTM is organized around central concepts Schema: term used to describe a person’s knowledge structure about a particular topic. -- Example: The knowledge structure I have concerning my role as a college professor. – Schemas that describe a sequence of activities are called scripts (e. g. , interactive warnings; goal is to interrupt existing “unsafe” scripts). Mental Models: type of schema that describes our understanding of system components, how a system works, and how to use it. Mental models that are shared by a large group of people are termed population stereotypes. Cognitive Maps: mental representations of spatial information (e. g. , layout of a city, campus, workplace). -- Edward Tolman’s work with rats -- Orientation usually reflects our view point -- Re-orienting our perspective through mental rotation is effortful.

Tolman’s Procedure 3 groups of rats placed in a complex maze ending at a food box. Group 1: Food reward every time they reached the end of the maze. Group 2: Day 1 – 10 = No reward; Day 11 – 17 = Rewarded. Group 3: No reward

Long-Term Memory: Implications for Design 1. Encourage regular use of information to increase frequency (of use) and recency. 2. Encourage active verbalization or reproduction of the to-be-remembered information (deep processing to form strong associations is best!). 3. Standardization can reduce memory load (e. g. , equipment, environments, displays, symbols, operating procedures). - Results in development of strong yet simple schemas and mental models that are applicable to a wide variety of circumstances. - Question: Are there any down sides to standardization from a cognitive perspective?

Long-Term Memory: Implications for Design 4. Use Memory Aids – Particularly important for infrequent or safety-critical tasks. – Putting “knowledge in the world” so that people don’t have to rely on “knowledge in the head” (LTM) Norman, 1988. 5. Carefully design to-be-remembered information – Info that must be remembered and retrieved unaided should have characteristics such as: • • • Be meaningful to an individual and semantically associated with other information Use concrete rather than abstract words whenever possible Use distinctive concepts and information (to reduce interference) Well-organized sets of information (group or otherwise associated) An item should be able to be guessed based on other info (Top-down Processing) Limit technical jargon 6. Design to support development of correct mental models – Apply the concept of visibility: users should immediately be able to determine the state of a device and the alternatives for action.

Facilitating Memory: Storage Memory is better if the “to-be-remembered” information is organized prior to memorization. – Material induced organization Organization is already provided in the stimuli – Subjectively induced organization Organized by having individuals use their own personal memories to help process to-be-remembered information. That is, by integrating it into existing mental structures, such as schemas, scripts, mental models.

Facilitating Memory: Encoding Specificity Cues that are present when the to-beremembered event occurs are effective retrieval cues. – The learning environment (studying and testing in the same room is better then changing rooms). – State-dependent memory (study wired; test wired? ) – Mood-dependent memory.

Facilitating Memory: Memory Mnemonics Method of Loci – Select a well-known location and mentally walk through and visualize a specific number of objects at that location (e. g. , furniture in each of several rooms of your apartment or house). – Establish an ordered list of these items that you commit to memory. – Learn to attach to-be-remembered items to the list. – Later, when you want to recall, take a walk back through the location and “see” what was placed there.

Facilitating Memory: Memory Mnemonics Pegword Method – Commit an ordered set of pegs to memory • Rhyming: One is a bun, two is a shoe, three is a tree…Well-known list: A is an apple, B is a bird, C is a cat… • New List: – 1 = tree – 2 = light switch – 3 = stool, and so on …. – Then visualize each to-be-remembered item interacting with your pegs (e. g. , a grocery list, terms for a test, etc. ). • Important to use elaborate imagery. Humor often helps!

Memory Failures: Episodic Memory for Events • Personal knowledge of memory of a specific event or episode is acquired by a single experience (high school prom; traumatic event). • Biases observed in episodic memory – Similar to top-down biases in perception; guided by expectations, mood, … • May be biased by plausible scenarios of how the episode in question might have been expected to unfold • Biases toward the “typical” may become more pronounced as time passes • May be influenced by suggestion • Applications – Eye-witness testimony • The Biggers Criteria (A Supreme court decision [Neil vs. Biggers, 1972] established 5 factors that should be considered when evaluating eyewitness testimony accuracy: certainty, view, attention, description, and time. – Accident investigation

Memory Failures: Sources of Bias at Each Stage Process Example Encoding Attention Witnesses tend to focus on the weapon used in a crime (salience) instead of on the perpetrator’s face or other features. Expectancy Witnesses may see what they expect to see. Storage Degraded memory/schema modification A degraded visual recollection may be replaced by an LTM schema of what a “typical criminal” looks like, or that an auto crash typically occurs at a high speed (causing the person to overestimate the actual speed). Biasing Events Chance encounter with a suspect in handcuffs prior to the line-up Retrieval Recognition Analogous to a signal detection task. We should maximize “hits” and “correct rejections, but should we also aim for minimizing a guilty bias?

Memory Failures: Prospective Memory for Future Events Failures of prospective memory: forgetting to do something in the future. – Reminder strategies • Low tech - String around the finger? Post-its? • High tech – Smart phones – Cognitive/behavioral strategies • verbally stating or physically taking some action regarding the required future activity the moment it is scheduled

Situation Awareness Definitions: – Users’ awareness of the meaning of dynamic (unexpected) changes in their environment. – The perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future (Endsley, 1995). Importance of SA for Human Factors: Perception (What’s going on? ) Understanding (Interpret the meaning of existing cues) Prediction (Predict the future implications of the available information).

Attention and Mental Resources • Selective attention allows us to process important information. We usually attend to one (auditory) channel at a given time. • Focused attention allows us to filter out unwanted information. • Sustained attention (Vigilance tasks; infrequent signals). • Divided Attention (Time-Sharing) allows us to perform more than one cognitive task by attending to both at once or by rapidly switching attention. – Time sharing among multiple tasks usually causes performance drop for one or more tasks, relative to baseline task performance. – Four factors determine the extent to which two or more tasks can be time-shared: Resource demand, Task Structure, Similarity, Resource allocation (or task management).

Performance Improvement Guidelines: Selective Attention Tasks • Reduce number of channels that must be monitored. • Emphasize relative importance of each channel to effectively focus attention. • Reduce stress to ensure appropriate channel sampling and train to ensure optimal channel scanning patterns. • Provide guidelines regarding probable location of signals. • Arrange visual channels to optimize scanning efficiency. • Prevent potential “masking” problems given multiple auditory channels. • Optimize rate of signal presentation (not too slow or too fast) and where possible, allow personal control over rate.

Performance Improvement Guidelines: Focused Attention Tasks • Make competing channels distinct (salience). • Physically separate irrelevant channels from channel of interest (organization). • Reduce the number of competing channels (information density). • Make the channel of interest different (salience).

Performance Improvement Guidelines: Sustained Attention Tasks • Vigilance tasks – human operators are very bad at tasks requiring sustained attention in order to detect infrequently occurring signals. • Consider the following: – Arrange appropriate rest-work schedules – Maximize signal conspicuity – Reduce uncertainty regarding signal occurrence/location – Arrange frequent training/feedback sessions – Maintain environmental conditions at optimal levels

Performance Improvement Guidelines: Divided Attention Tasks • Minimize potential sources of information • Prioritize task importance ahead of time • Minimize task difficulty and select dissimilar dual tasks • Capitalize on “automatic processing” via over-learning

Mental Workload • Amount of cognitive resources available in a person versus amount of resources demanded by the task • Measuring mental workload – Primary task measurement – Secondary task measurement – Psychological measures – Subjective measures

Limitations • Can’t assume that information will be processed just because it is presented. • People can only process so much information period of time. • For complex displays-only a small amount of info will be attended to at one time. – The information most critical to task performance must be provided in a way that will attract attention (conspicuity/salience).

Multiple Resources • Visual and auditory processing requires separate resources. • There are multiple kinds of informationprocessing resources that allow time sharing to be more successful. – Time Sharing (optimize resources optimally) – Stages: Early vs. Late (resources for perceptual processing/central processing separate from those used for response selection/execution). – Input Modalities: Visual vs. Auditory – Processing Codes: Spatial vs. Verbal in Early Processing and Manual vs. Vocal in Responding

Input Modalities • Humans are generally better at dividing attention between one visual and one auditory input (cross-modal time-sharing) than between 2 visual or 2 auditory channels (intramodal time-sharing). • Dual task interference is generally reduced by spreading input across visual and auditory modalities

Effect of presentation modality in direct-to-consumer (DTC) prescription drug television advertisements Applied Ergonomics, 45(5), 1330 -6, Wogalter, M. S. , Shaver, E. F. , Kalsher, M. J. Direct-to-consumer (DTC) drug advertising markets medications requiring a physician's script to the general public. In television advertising, risk disclosures (such as side effects and contraindications) may be communicated in either auditory (voice) or visual (text) or both in the commercials. This research examines presentation modality factors affecting the communication of the risk disclosures in DTC prescription drug television commercials. The results showed that risk disclosures presented either visually only or both visually and auditorily increased recall and recognition compared to no presentation. Risk disclosures presented redundantly in both the visual and auditory modalities produced the highest recall and recognition. Visual only produced better performance than auditory only. Simultaneous presentation of non-risk information together with risk disclosures produced lower recall and recognition compared to risk disclosures alone-without concurrent non-risk information. Implications for the design of DTC prescription drug television commercials and other audio-visual presentations of risk information including on the Internet, are discussed.

Processing Codes • Spatial and verbal processing (codes) depend on distinct resources • To the extent that any two tasks draw on separate, rather than common resources, time-sharing is more efficient – Less likely to impact performance of concurrent tasks

Confusion • When the same resources are used for two tasks, the amount of interference between them is increased or decreased by the difference in similarity of the information being processed. • Similarity induces confusion. • When two tasks are confused, it sometimes produces cross-talk – Output intended for one task inadvertently gets delivered to the other.

Guidelines for maximizing performance for concurrent tasks 1. Task Re-design. Do careful assessment of timesharing requirements and make them less resourcedemanding whenever possible. 2. Interface re-design. Off-load heavily demanded resources (e. g. , supplement voice display if visual display is too attention-demanding). 3. If we are performing a primary task that imposes a heavy mental workload—it is unlikely we will be able to add a second task successfully. 4. Training. 5. Automation.