Chapter 5 Quiz: Your Brain Online

Section A: Multiple Choice (Questions 1–12)

Select the best answer for each question.

Question 1

George Miller's 1956 paper on short-term memory capacity proposed that humans could hold approximately how many items in working memory?

A) 4 ± 1 items B) 7 ± 2 items C) 10 ± 3 items D) 12 ± 2 items

Answer: B Explanation: Miller's famous paper "The Magical Number Seven, Plus or Minus Two" proposed a capacity of approximately seven items. More recent work by Nelson Cowan has revised this estimate downward to approximately 4 ± 1 chunks, but Miller's original formulation remains the historically significant finding.

Question 2

According to the Ward et al. (2017) study on smartphone presence and cognitive capacity, which condition produced the best performance on working memory and fluid intelligence tasks?

A) Phone face-down on the desk B) Phone in the participant's pocket C) Phone in another room entirely D) Phone face-up on the desk, silenced

Answer: C Explanation: The study found a gradient of performance: phone on desk < phone in pocket or bag < phone in another room. Participants whose phones were in another room performed significantly better, suggesting that even the awareness of the phone's potential accessibility creates attentional suppression costs.

Question 3

The default mode network (DMN) is best described as:

A) The brain's threat-detection system, active during danger B) A set of regions active during externally-directed focused tasks C) A network active during self-referential thought, mind-wandering, and internal processing D) The brain's primary visual processing pathway

Answer: C Explanation: The DMN, identified formally by Marcus Raichle and colleagues, is active during internally-directed states including mind-wandering, autobiographical memory, future simulation, and social cognition. It was initially called "task-negative" because it was suppressed during focused external tasks, but this framing understated its active and important functions.

Question 4

In cognitive load theory, which type of cognitive load represents the productive effort of constructing and automating mental schemas?

A) Intrinsic load B) Extraneous load C) Germane load D) Residual load

Answer: C Explanation: Germane cognitive load is the effort invested in genuine learning — constructing schemas that integrate new information with existing knowledge. Intrinsic load comes from the material's inherent complexity, and extraneous load comes from irrelevant features of the environment or format that consume working memory without contributing to learning.

Question 5

The "low road" in Joseph LeDoux's framework for emotional processing refers to:

A) The slow, deliberate cortical evaluation of emotional stimuli B) The fast subcortical pathway from sensory input to amygdala response, bypassing conscious evaluation C) The pathway from the prefrontal cortex to the amygdala that regulates emotional responses D) The diffuse attentional mode associated with low arousal

Answer: B Explanation: LeDoux's "low road" describes the rapid thalamo-amygdalar pathway that enables the amygdala to respond to potentially threatening or emotionally significant stimuli before slower cortical processing has completed its analysis. This pre-cortical response initiates physiological and cognitive cascades that the deliberate mind does not choose.

Question 6

Sophie Leroy's research on "attention residue" found that:

A) Focused attention leaves residual capacity for other tasks B) Interrupted tasks leave cognitive traces that persist and reduce performance on subsequent tasks C) Dopamine residue from reward experiences enhances subsequent attention D) The brain retains emotional memories more vividly than neutral ones

Answer: B Explanation: Leroy demonstrated that switching away from a task before reaching a natural stopping point leaves part of attentional capacity allocated to the incomplete task. This "residue" reduces performance on the new task because working memory is partially still engaged with the interrupted one.

Question 7

The salience network is primarily anchored by which brain structures?

A) The hippocampus and the cerebellum B) The occipital cortex and parietal lobe C) The anterior insula and the anterior cingulate cortex D) The basal ganglia and the ventral tegmental area

Answer: C Explanation: The salience network is centered on the anterior insula and anterior cingulate cortex. It functions as a significance-detection system, determining which stimuli are relevant enough to interrupt current attentional states and recruit processing resources.

Question 8

Which of the following best describes dopamine's actual function in reward learning, as opposed to the popular account?

A) Dopamine signals pleasure and is released in proportion to how enjoyable an experience is B) Dopamine signals prediction error — the discrepancy between expected and actual reward C) Dopamine suppresses the habit system to prevent compulsive behavior D) Dopamine is released only when social bonds are formed or strengthened

Answer: B Explanation: Dopamine in the mesolimbic system signals prediction error: it fires when an unexpected reward arrives and is suppressed when an expected reward fails to appear. This makes dopamine a learning signal that teaches the brain what predicts good outcomes, rather than simply what feels good.

Question 9

Why are variable reward schedules more powerful than fixed reward schedules in driving persistent behavior?

A) Variable rewards are larger on average than fixed rewards B) Variable schedules prevent habituation of dopamine prediction circuits by maintaining perpetually high prediction error C) Variable schedules require less effort to receive rewards D) Fixed schedules produce faster learning but shorter retention

Answer: B Explanation: Variable (intermittent) reinforcement keeps prediction error high because the brain cannot establish reliable expectations for when or how large the reward will be. The dopamine signal does not habituate, keeping the behavior strongly reinforced. This is the principle underlying slot machines, social media feeds, and many other compelling engagement systems.

Question 10

The concept of "continuous partial attention," coined by Linda Stone, describes:

A) The brain's tendency to process emotional content automatically B) A state of low-level awareness across multiple information streams without full engagement with any of them C) The partial recovery of attention after a period of complete rest D) The dimming of attention that occurs in the last hour before sleep

Answer: B Explanation: Stone's term describes an emerging attentional mode in technology-intensive environments — monitoring multiple streams simultaneously without deep engagement with any single one. This is distinct from multitasking and from focused attention, and has become an increasingly common default mode for heavy smartphone users.

Question 11

The research of Marily Oppezzo and colleagues on walking and creativity found that:

A) Walking while listening to educational audio increases creative output B) Any form of physical exercise significantly boosts creative performance C) Walking produces measurable increases in divergent thinking, but only when the walk does not involve screen use D) Creativity is best supported by focused sedentary work rather than movement

Answer: C Explanation: Oppezzo's research found that walking enhanced divergent thinking (a key component of creativity), but this benefit was reduced or eliminated when the walking involved external visual or cognitive stimulation. This supports the view that the benefit comes from the mind-wandering and DMN engagement that unoccupied walking permits.

Question 12

Which of the following is the most accurate description of why heavy social media users might find reading a book or studying increasingly difficult over time?

A) Social media causes measurable brain damage that reduces intelligence B) Prolonged social media use eliminates the brain's capacity for focused attention permanently C) The salience network becomes calibrated to high-stimulation content, making low-stimulation activities comparatively less able to sustain attentional engagement D) Social media use depletes serotonin reserves necessary for mood-dependent learning

Answer: C Explanation: The chapter describes attentional sensitization — the process by which the salience system's baseline threshold shifts upward with continuous high-stimulation input. Low-stimulation activities do not become impossible, but they become comparatively less engaging as the brain's calibration adjusts to expect higher-intensity input. This is reversible rather than permanent.

Section B: Short Answer (Questions 13–17)

Answer each question in 3–5 sentences.

Question 13

Explain the difference between working memory depletion through loading and working memory depletion through suppression. Give one example of each relevant to social media use.

Model Answer: Working memory depletion through loading occurs when the cognitive workspace is filled with content that must be actively maintained — for example, tracking multiple simultaneous conversations or following a rapidly-cut video sequence that requires continuous contextual updating. Depletion through suppression occurs when the prefrontal cortex must actively inhibit competing stimuli, which draws on the same executive resources as the primary task — for example, sitting near a phone and actively trying not to check it. Both forms of depletion reduce the working memory capacity available for demanding tasks like studying or problem-solving.

Question 14

Why is the characterization of the default mode network as a "rest state" misleading? Name at least three functions the DMN actively supports.

Model Answer: The characterization of the DMN as a rest state is misleading because it implies the network is idle or unproductive when not engaged in external tasks. In fact, the DMN is actively conducting important cognitive work during states of low external demand. It supports autobiographical memory consolidation (integrating experiences into long-term self-narrative), future simulation (generating mental models of possible future scenarios that underlie planning and goal management), social cognition and theory of mind (understanding others' mental states), and creative insight (the incubation processes that produce divergent thinking and problem-solving breakthroughs).

Question 15

Explain what "attention residue" is and describe two specific social media behaviors that would predictably create it.

Model Answer: Attention residue, as documented by Sophie Leroy, refers to the cognitive traces that remain allocated to an incomplete task when attention is switched away from it before reaching a natural stopping point. These traces occupy working memory and reduce performance on the new task. Two social media behaviors that predictably create attention residue are: (1) briefly checking a notification mid-study session, which opens an incomplete processing task (the unresolved content or conversation), and (2) scrolling briefly through a feed that contains emotionally activating content, which initiates emotional processing cycles that continue demanding cognitive resources after the phone is put down.

Question 16

Describe the cue-routine-reward structure of a typical social media habit. At which stage is behavior most amenable to intentional change, and why?

Model Answer: In a typical social media habit, the cue might be an internal state (boredom, frustration, or a pause in activity) or an environmental trigger (a notification sound or vibration). The routine is the sequence of unlocking the phone, opening the app, and scrolling. The reward is the variable, intermittent delivery of emotionally or socially engaging content. The behavior is generally most amenable to change at the cue stage, because by the time the routine has been initiated, the automated nature of basal ganglia-encoded behavior makes stopping difficult; environmental design changes — removing the phone from sight, using app timers, or placing the phone in another room — address the cue before the routine can fire.

Question 17

Explain the negativity bias and describe how social media algorithms interact with it to shape the emotional character of content feeds.

Model Answer: The negativity bias is the tendency for the brain to assign greater attentional weight, faster processing, and more thorough cognitive elaboration to negative information (threats, losses, social rejection) compared to positive information of equivalent objective significance. This asymmetry is an evolutionary adaptation reflecting the higher cost of ignoring threats compared to missing positive opportunities. Social media algorithms, optimizing for engagement, have empirically discovered that content triggering strong emotional responses — particularly anger, outrage, and fear — generates more likes, shares, comments, and viewing time than positive or neutral content. As a result, recommendation systems amplify emotionally negative and threat-relevant content, creating feeds that are systematically biased toward the types of stimuli that produce the most physiological and attentional response in users with a negativity-biased nervous system.

Section C: Applied Questions (Questions 18–22)

These questions ask you to apply chapter concepts to new scenarios.

Question 18: Applied Analysis

A school district is considering a policy requiring students to place their phones in locked pouches at the start of each class period, retrieving them at the end. Based on the Ward et al. (2017) findings and the mechanisms described in this chapter, would you expect this policy to improve academic performance? What would you predict about the magnitude of the effect, who would benefit most, and what potential costs the policy might have?

Model Answer: Based on Ward et al., the policy would be expected to improve cognitive performance during class. The study found that phone proximity — even face-down and silenced — reduced working memory and fluid intelligence performance, with the effect largest for students high in smartphone dependence. Removing phones entirely would eliminate both the active-use cost and the suppression cost, placing students in the best-performing "phone in another room" condition. The policy would likely benefit high-dependence users most significantly. Potential costs to consider include: students who use phones for accessibility accommodations, students who legitimately need phones for medical reasons, the stress-related cognitive costs of students who are highly anxious about missing social communications, and the possibility that the policy reduces student agency and trust in ways that produce their own academic effects.

Question 19: Scenario Analysis

A 22-year-old graduate student, Marcus, reports that he can study productively while listening to music with lyrics, chatting briefly with friends on his phone, and reviewing research articles simultaneously. He says he has always been a good multitasker and his grades support this. How would you evaluate his self-assessment using the evidence from this chapter? What are the most likely explanations for any discrepancy between his perception and the scientific evidence?

Model Answer: Marcus's self-assessment conflicts with the strong empirical evidence against genuine multitasking. David Meyer's research consistently shows that for cognitively demanding tasks, simultaneous performance is not achievable — what feels like multitasking is rapid task-switching with associated costs. Several factors could explain the discrepancy. First, Marcus may be accurate that his grades are good — but we cannot know whether his performance in divided-attention conditions exceeds or falls below what his performance in focused conditions would produce, so the comparison is missing. Second, high performers often have larger reserves of the executive resources that inhibition and task-switching consume, meaning the costs are real but remain below a threshold that affects his final outcomes. Third, humans are poor judges of their own cognitive performance in divided-attention conditions — the subjective experience of smooth multitasking does not accurately reflect the quality decrements that performance measures reveal. Fourth, some of his concurrent activities (music) may be sufficiently automated that they do not substantially compete for working memory, making his situation closer to one-and-a-half tasks than true dual-tasking.

Question 20: Design Critique

A technology company proposes a new social media feature called "Mindful Mode." When activated, Mindful Mode removes notification badges, disables autoplay, reduces visual clutter in the interface, and presents content in a single linear format without recommended related content. Based on the mechanisms in this chapter, evaluate which cognitive problems this feature would address, which it would not address, and what you would add to the feature if you were advising the design team.

Model Answer: Mindful Mode would address several extraneous cognitive load sources: notification badges are potent salience triggers and habit cues; removing them reduces both the distraction value and the suppression cost when users are trying not to check. Disabling autoplay removes one mechanism of habit loop perpetuation (the elimination of natural stopping points). Reducing visual clutter lowers the extraneous load from competing interface elements. Removing recommended content reduces the variable reward structure that drives compulsive engagement.

What the feature would not address: the emotional content of whatever users do view, which activates the amygdala regardless of format. The feature does not address the fact that the platform is still available as a habit cue when boredom or unstructured time occurs. It does not address social comparison effects from the content that is shown. It does not protect DMN function, since even reduced-stimulation social media use is still externally-directed.

Additions to recommend: content warnings that create a deliberate pause before emotionally activating material; session time limits with natural stopping-point design; a cooldown feature that introduces a 10-minute delay before the app can be reopened after closing; and a design that surfaces stopping points rather than eliminating them.

Question 21: Synthesis Question

Maya's 50-minute TikTok session and her subsequent difficulty studying can be explained through multiple mechanisms simultaneously. Using at least five distinct mechanisms from this chapter, construct a coherent multi-system account of why she found it so difficult to focus on calculus after closing the app.

Model Answer: Five mechanisms contribute to Maya's post-TikTok studying difficulty:

(1) Attentional transition cost: Maya spent 50 minutes in a high-stimulation external-attention state. Returning to the focused attention required for calculus requires a neurological mode transition — recruiting prefrontal circuits, suppressing ambient monitoring, loading working memory with task-relevant context — that takes 15-20 minutes to complete. She is functionally in the wrong attentional gear.

(2) Extraneous cognitive load accumulation: Each emotionally activating video in her session initiated processing cycles that did not resolve when the video ended. These cycles continue demanding working memory resources as the brain attempts to complete its analysis of the content, reducing the capacity available for the problem set.

(3) Attention residue: Multiple incomplete processing tasks — the unresolved loneliness discussion, the political content, the ongoing social situations she observed — remain as open items in her cognitive workspace, pulling at attention as she attempts to engage with derivatives.

(4) DMN suppression: 50 minutes of external stimulation suppressed her default mode network throughout. The emotional processing and self-referential integration that would normally happen in unoccupied moments has not occurred, leaving her emotionally unsettled without the reflective capacity to process why.

(5) Physiological arousal from negative content: The political content triggered a genuine cortisol and adrenaline response. This physiological activation — real stress hormones in the bloodstream — takes time to metabolize, and its presence impairs the calm, focused state that mathematical reasoning requires.

Question 22: Evaluative Question

The chapter concludes that "the brain is not broken; it is being hijacked." Evaluate this framing. What does it explain well? What important nuances does it risk obscuring? Is the hijacking metaphor scientifically and ethically apt?

Model Answer: The hijacking metaphor serves several useful purposes. It correctly locates the problem in the design of the technological environment rather than in individual cognitive deficit, which counters the moralism that often characterizes discussions of screen time and self-control. It emphasizes agency (hijacking implies that control is taken from someone who legitimately has it) and suggests that reclaiming that agency is meaningful and possible. It accurately conveys that the exploitation of cognitive vulnerabilities is systematic and (at least in part) intentional.

The metaphor has limitations. First, hijacking implies a single decisive event, whereas the process is gradual, bidirectional, and involves the user's own choices at many points. Second, it may understate the genuine value many users derive from social media, casting all engagement as coerced when much of it is volitional and beneficial. Third, it may imply that users are passive victims with no role to play, when the evidence on meta-cognition and environmental design suggests that informed users can take meaningful protective steps. Fourth, the metaphor does not distinguish between platforms or use cases — some social media use patterns may impose minimal cognitive costs while others are genuinely harmful.

The "not broken" component is scientifically and ethically important: it frames susceptibility as a feature of healthy, evolved brains rather than as pathology, which avoids stigma and supports the autonomy-centered framing that the chapter's conclusion builds toward. On balance, the metaphor is more apt than not, as long as readers understand it as a simplified characterization of a complex bidirectional process.