Chapter 18: Why Rats Can't Go Grocery Shopping

Chapter Overview:

• Main Focus: This chapter explores the ability of primates, and especially humans, to anticipate future needs and make plans accordingly. Bennett argues that this capacity for future planning represents a significant cognitive advance and connects it to the evolution of episodic memory and the prefrontal cortex. He uses the illustrative example of grocery shopping to highlight that, while a rat may be able to navigate to where food currently exists, it cannot plan ahead and go gather food it does not want now but which it will want at some point in the future (Bennett, 2023, p. 283, 288).
• Objectives:
• Explain the concept of future planning and its importance in primate intelligence.
• Discuss the Bischof-Kohler hypothesis and its limitations.
• Explore the neural basis of future planning, linking it to episodic memory and simulation.
• Contrast the planning abilities of primates with those of other mammals.
• Highlight the challenges of implementing future planning in AI.
• Fit into Book's Structure: This chapter expands on the previous discussion of mentalizing and theory of mind (Chapters 15-17) by exploring how these abilities contribute to planning for future needs. It further strengthens Bennett's argument for the unique nature of human intelligence. He argues that the capacity for mental time travel may be what allowed humans to engage in cooperative behavior over large groups by creating a capacity to trust other people’s future actions, enabling complex social contracts (Bennett, 2023, p. 306).

Key Terms and Concepts:

• Future Planning: The ability to anticipate future needs and make plans accordingly. Relevance: This is the central cognitive ability explored in the chapter.
• Bischof-Kohler Hypothesis: The hypothesis that only humans can make plans based on future needs, rather than just current needs. Relevance: Bennett challenges this hypothesis by providing evidence of future planning in other primates.
• Episodic Memory: Memory for specific past events and experiences. Relevance: Episodic memory provides the raw material for simulating future scenarios and anticipating needs.
• Prefrontal Cortex (PFC): A brain region involved in planning, decision-making, and working memory. Relevance: The PFC is crucial for simulating future scenarios and making plans based on those simulations. Specifically, the author mentions that damage to the PFC impairs the ability of primates to engage in episodic memory recall, counterfactual learning and vicarious trial and error, all of which require simulation of something which is not immediately present (Bennett, 2023, p. 207-208). This implies that the PFC is what determines what gets simulated in the neocortex and when and further, that this same structure enables primates and humans to project themselves into future scenarios and past scenarios and even to consider alternative possible scenarios that did not occur (counterfactuals). This highlights how episodic memory and future planning may be two sides of the same coin—the same process of “mental time travel” applied to different problems. It is only primates and humans who exhibit such mental time travel abilities (Bennett, 2023, p. 296).
• Mental Time Travel: The ability to mentally project oneself into the past or future. Relevance: This capacity is essential for future planning and episodic memory.
• Frugivory: A diet consisting primarily of fruit. Relevance: Bennett discusses the challenges of frugivory, such as the need to anticipate the ripening of fruit and plan foraging routes accordingly. He argues that these pressures might have led to the development of ‘future planning’ capabilities in early primates. He contrasts this with the easier problem faced by folivores (leaf-eaters) whose food sources were relatively unchanging and were rarely located in sparse and limited regions of their environment. Similarly, carnivores do not face the same problem, since hunting is possible whenever an animal is hungry, which explains why both folivores and carnivores never developed the same “future planning” mechanisms present in frugivores and primates (Bennett, 2023, p. 282-283).
• Ecological Brain Hypothesis: The hypothesis that the demands of navigating complex environments, rather than social pressures, drove the evolution of large brains in primates. Relevance: This hypothesis provides an alternative explanation for primate brain evolution and is discussed in relation to the challenges of frugivory. It’s important to note that Bennett ultimately suggests that the social-brain hypothesis and the ecological-brain hypothesis are two sides of the same coin; the capacity to ‘mentalize’ might have been equally valuable when it comes to getting the best fruit as it was in navigating complex social hierarchies (Bennett, 2023, p. 297).

Key Figures:

• Doris Bischof-Köhler and Norbert Bischof: Psychologists who proposed the Bischof-Kohler hypothesis. Relevance: Their hypothesis is used as a starting point for the discussion of future planning, although Bennett challenges its exclusivity to humans.
• Thomas Suddendorf: A psychologist known for his work on mental time travel and the Bischof-Kohler hypothesis. Relevance: Suddendorf's work is discussed in the context of the limitations of attributing future planning only to humans, echoing Bennett's arguments (Bennett, 2023, p. 284, 293). He notes that Suddendorf argued against the idea that other animals could anticipate future needs based on experiments with rats who were unable to forgo a smaller current reward for access to water later despite being made thirsty, and whose survival could have been improved had they shown such foresight (Bennett, 2023, p. 286). However, similar experiments with squirrel monkeys, who could pass the “future planning” test, challenged this conclusion (Bennett, 2023, p. 287). The author does mention that Suddendorf’s conjecture about this unique ability of primates being a special case of ‘simultaneously representing conflicting mental states’ (Bennett, 2023, p. 287) is insightful and aligns well with his framework, since theory of mind, which is also present in primates and not many other mammals, is exactly this process of simulating an internal mental state which does not align with the current sensory input or state (Bennett, 2023, p. 286). Bennett’s later argument about theory of mind as being an extension of an aPFC model of one’s self aligns nicely with this perspective (Bennett, 2023, p. 296). This is tied together by his observation that damage to the same parts of the neocortex which impair theory-of-mind abilities also impair future-planning abilities, suggesting that these may indeed be two sides of the same coin (Bennett, 2023, p. 287).
• Miriam Naqshbandi and William Roberts: Researchers who studied future planning in squirrel monkeys. Relevance: Their work provides evidence against the Bischof-Kohler hypothesis, demonstrating that other primates can anticipate future needs.
• Alex DeCasien: An NYU researcher who studied links between dietary complexity, social group size, and brain size in primates (Bennett, 2023, p. 283-284). Relevance: DeCasien’s work challenges the social brain hypothesis, demonstrating that the complexities associated with foraging fruit may have been a more important pressure in driving up brain size and intelligence in early primates than social dynamics. It’s important to note, however, that Bennett does not believe this disproves the “social” brain hypothesis; the author ultimately argues that both the social and ecological explanations for primate intelligence may be equally important and are two sides of the same coin (Bennett, 2023, p. 297).

Central Thesis and Supporting Arguments:

• Central Thesis: The capacity to anticipate future needs and make plans accordingly, what is sometimes called ‘mental time travel’, is a cognitive ability present in primates, not just humans, which is closely related to other simulating capabilities (Ch. 3, 11, & 12) in the neocortex such as episodic memory and counterfactual learning, and these may have emerged together in primates to solve both problems associated with foraging for food and navigating complex social situations. The author argues that this ability was enabled by the new neural structures in the primate brain, specifically in the neocortex, which may have expanded in response to the pressures of needing to engage in theory of mind (Ch. 16).
• Supporting Arguments:
• Primate studies: Squirrel monkeys, and other primates, demonstrate an ability to anticipate future needs (like thirst) in experimental settings.
• Challenges of frugivory: The need to predict the ripening of fruit and plan foraging routes may have driven the evolution of future planning in primates.
• Neural basis: The prefrontal cortex, a brain region involved in planning and decision-making, is likely crucial for anticipating future needs, and is linked to episodic memory and simulating (Ch. 3 & 12) abilities.
• Evolutionary advantage: Future planning enhances survival and reproduction by allowing primates to prepare for future challenges and opportunities. This is especially true for social primates who might not be individually strong, but are able to form coalitions or engage in politics and other social ‘machinations’ (Ch. 15) to improve their position. The ability to make deals with future promises (“I’ll support you in this conflict later if you help me now”) is not possible without some capacity for trusting other people's future intentions, which may be tied to a primate’s capacity for mental time travel.

Observations and Insights:

• The Bischof-Kohler hypothesis is not entirely accurate: Other primates, not just humans, can plan for the future.
• Future planning is computationally demanding: It requires simulating future scenarios and evaluating potential outcomes.
• Mental time travel as a unifying concept: This ability underlies both episodic memory (remembering the past) and future planning (imagining the future), highlighting the importance of simulating what is not immediately present.

Unique Interpretations and Unconventional Ideas:

• The connection between future planning and theory of mind: Bennett suggests that these abilities may share underlying neural mechanisms, highlighting how mental time travel is similar regardless of whether it is applied to another’s current mind or to one’s own future or past minds.
• The argument that future-planning capabilities and episodic memory capabilities in humans are adaptations originally selected for maximizing efficient foraging strategies: The author mentions that episodic memory is useful not only for remembering what happened in the past but also for predicting what might happen in the future (Bennett, 2023, p. 197). He highlights that rats, for instance, can perform far better on certain episodic memory tasks than they would if they were to use reinforcement learning alone (Bennett, 2023, p. 198) which suggests that episodic memory itself may be a simulation not just a recording (Bennett, 2023, p. 208). He then links this same capacity for mental “time travel” to primates’ capacity to plan for future needs by offering the insight that a squirrel monkey can perform just as well as a human on mental time travel tasks which are not social (Bennett, 2023, p. 288). This further emphasizes that human’s capacity to plan ahead was not something new and special but an extension of similar capabilities found in earlier primates.

Problems and Solutions:

Categorical Items:

Bennett compares and contrasts goal-directed (model-based) and habitual (model-free) behaviors in primates.

Literature and References: (Refer to the book's bibliography for full citations)

• Works by Bischof-Köhler, Bischof, Suddendorf, Naqshbandi, Roberts, and DeCasien are cited.
• Studies on future planning, episodic memory, and the prefrontal cortex in humans and other primates are referenced.

Areas for Further Research:

• The precise neural mechanisms underlying future planning require further investigation.
• The development of future planning abilities across the lifespan and in different species warrants further study.
• The role of emotions and social factors in future planning needs more research.

Critical Analysis:

• Strengths: This chapter challenges anthropocentric views of intelligence by demonstrating future planning in other primates. The connections to episodic memory, simulation, and the prefrontal cortex provide a plausible neural explanation for this ability.
• Weaknesses: The discussion of the ecological brain hypothesis could be expanded. The chapter focuses primarily on primates, and further research is needed to understand the extent of future planning abilities in other animals.

Practical Applications:

• Understanding the cognitive basis of future planning can inform educational strategies, therapeutic interventions for individuals with planning deficits, and the development of AI systems capable of long-term strategizing.

Connections to Other Chapters:

• Chapter 16 (How to Model Other Minds): This chapter builds upon the previous chapter's discussion of theory of mind by connecting it to mental time travel, arguing that humans are able to “transfer” such future plans to others via language (Ch. 19), which enables the coordination of behavior on a massive scale and the development of human civilizations (Bennett, 2023, p. 302-303). He also reinforces his argument that the gPFC and PSC are the key neural structures involved in theory of mind, since damage to these areas also impairs episodic future planning capabilities in primates (Bennett, 2023, p. 287), which supports his view that theory of mind is merely an application of these same underlying circuits for modeling one’s own future internal states.
• Chapters 11, 12, and 13 (Neocortex, Simulating, and Model-Based Reinforcement Learning): This chapter connects future planning to the neocortex's simulation capabilities, highlighting the role of the prefrontal cortex in controlling and directing these simulations.
• Chapters 19 & 20: This chapter foreshadows how the ability to anticipate future needs and engage in long-term planning played a crucial role in human cognitive evolution, setting the stage for the discussions of language and cumulative culture and tying together the five breakthroughs model, since the key advantage of human language, the author suggests, is that it enables the creation of what might be called “shared simulations.” If two humans hear the same sequence of sounds, they will both tend to render the same internal movie in their heads. This shared mental experience is the foundation of human culture, enabling humans to cooperate on a massive scale, develop institutions, tell stories about the past, make plans about the future, and, to some degree, even have laws and morals. Human language makes the neocortex’s ‘simulator’ into a ‘shared simulator’ that can communicate and transfer thoughts from one mind to another, allowing for knowledge to persist and accumulate across generations, leading to cumulative cultural evolution and the extraordinary ascent of human civilizations (Bennett, 2023, p. 306-307). This shared simulated experience of the human language is made possible, the author argues, only because human brains have a capacity for understanding theory of mind and for being able to simulate other minds (Bennett, 2023, p. 307, 353). This is because the meaning and the intent behind human language are often not explicit in the specific sequence of words spoken or heard, and thus a degree of ‘mind reading’ is required to effectively communicate, especially when humans use metaphors or other rhetorical devices, and also when humans are attempting to convey things like irony or sarcasm where the literal meaning of the words themselves does not explicitly communicate what the other mind intended to convey. And it is because the gPFC and PSC are the regions of the human brain associated with theory of mind, and these regions are also the same areas associated with language processing (Bennett, 2023, p. 353) and human self-awareness, which explains how mentalizing about one’s self, and mentalizing about another mind, may be closely related.

Surprising, Interesting, and Novel Ideas:

• Primates, not just humans, exhibit future planning: This challenges the Bischof-Kohler hypothesis and expands our understanding of animal cognition (Bennett, 2023, p. 287-288).
• The link between future planning, theory of mind, and episodic memory: This suggests a unified framework for understanding mental time travel and its role in intelligent behavior (Bennett, 2023, p. 286-287).
• The challenges of frugivory as a potential driver of primate intelligence: This ecological perspective offers an alternative to the social brain hypothesis, although Bennett suggests that both factors likely played a role (Bennett, 2023, p. 283-284).

Discussion Questions:

• How might the ability to anticipate future needs have contributed to the evolutionary success of primates?
• What are the neural and computational limitations on future planning, and how might these limitations be overcome?
• How do different species' planning abilities reflect their ecological niche and evolutionary history?
• What are the ethical considerations of creating AI systems capable of long-term planning and goal-directed behavior?
• How might our understanding of future planning in the brain be applied to improve human decision-making and address problems like procrastination and impulsivity?

Visual Representation:

[Past Experiences (Episodic Memory)] + [Current Needs] + [Model of the World] --> [Simulation of Future Scenarios (PFC)] --> [Future Planning]

TL;DR: