This is Part 3 of a four-part blog series exploring how the brain generates meaning. In Parts 1 and 2, I traced meaning from its origins in goal-directed life forms through its implementation in neural mechanisms. But human meaning extends beyond individual brains. We share meanings, argue about them, and record them in books. How did biological meaning become social?

This isn’t merely about communication but about a fundamental transformation in how meaning works. Animal meanings are largely immediate and individual. Human meanings are public, abstract, symbolic, and cumulative across generations.

Signs Versus Symbols

Let’s start with a crucial distinction emphasized in biosemiotics—the study of sign processes in living systems—and articulated by Jablonka and Ginsburg: signs versus symbols.[1]

• Signs are meaningful signals that organisms respond to: a scent trail means food, a posture means threat. These work through direct association, learned or evolved responses to specific cues. They’re context-bound and largely automatic.
• Symbols are qualitatively different. They refer by convention rather than natural association. The word "tree" doesn’t resemble a tree, doesn’t smell like one, and doesn’t trigger climbing. It refers through arbitrary social agreement. Symbols can be used flexibly: applied to absent objects, combined in novel ways, and embedded in conditional and counterfactual statements.

This flexibility requires analogical reasoning, the capacity to map shared relational structure across domains.[2] The progression from signs to symbols marks a transformation in semiotic capacity, from interpretation bound to immediate contexts to interpretation that can range over absent objects, hypothetical scenarios, and abstract relations.

The Grounding Problem Revisited

But symbols create a puzzle. If a word is meaningful only through convention—through its relations to other words—how does such a self-contained system ever connect to the world it is supposed to describe? This is the classic symbol grounding problem.[3]

Philosophers long struggled because influential theories treated symbols as self-contained tokens in an internal language of thought, connected primarily to other symbols. But seen through Part 2’s neural semantics lens, the problem largely dissolves.

Symbols aren’t grounded in other symbols alone; they’re grounded in the same sensorimotor, emotional, and evaluative networks grounding nonsymbolic meanings. When you understand "tree," your brain activates distributed patterns spanning visual features, motor programs for climbing, memories of specific trees, and emotional associations.[4] Words also gain meaning through relationships to other words, but these aren’t free-floating relationships—each word in the network is itself grounded in sensorimotor experience.

This grounding happens through active exploration.[5] Infants learn object properties through causal intervention: I can pick that up; I can eat that; that can hurt me; that moves by itself. They discover affordances by acting on the world (affordances are the action possibilities that the environment offers to an organism). This grounding in personal agency is why symbols never fully detach from bodily experience.

Consider "coffee." Through experience, that word activates sensory and motor patterns: warmth, bitter taste, arousal. Meaning is grounded in distributed brain patterns that can be reactivated to recreate experiences of taste, touch, and feeling.[6]

Even highly abstract concepts are grounded, though indirectly. "Democracy" doesn’t activate any single, specific sensory pattern, but it connects through multiple links to concepts that do: voting, speaking, gathering, equality. Abstract meaning emerges from the reactivation and recombination of perceptual and motor representations built on more basic embodied meanings.[6]

Thus, abstract concepts remain tethered—often through long metaphorical and analogical chains—to bodily experience.[2] Meaning stays grounded while becoming increasingly abstract, shareable, and stabilized through social conventions.

Douglas Hofstadter offers still deeper insights on how meaning emerges: "When a system of ‘meaningless’ symbols has patterns in it that accurately track, or mirror, various phenomena in the world, then that tracking or mirroring imbues the symbols with some degree of meaning—indeed, such tracking or mirroring is no less and no more than what meaning is." Yet such patterns must ultimately be evaluated and used by living systems with goals. Hofstadter further argues that particularly complex, recursive patterns—what he calls “strange loops,” self-referential structures that fold back on themselves—may be key to the emergence of consciousness.[7]

Shared Attention Is the Key to Children Learning That Symbols Have Meaning

How do children acquire symbolic reference capacity? They don’t start with it; infants respond to signs like any animal. Symbolic meaning emerges gradually through a specific developmental pathway.

Research reveals that language builds on prior capacities for shared attention and cooperative communication.[8] Before infants use words symbolically, they already understand others as intentional agents with goals. They point not just to request but to share attention.

This joint attention capacity, coordinating attention with another agent on a third thing, is foundational for symbols. A symbol works only if the speaker and hearer agree on what it refers to. This requires not just individual understanding but mutual knowledge of understanding: knowing that the other knows what you mean.

Once a child grasps that words can refer—that sounds can stand for things by mutual agreement—vocabulary explosion follows. Symbols bootstrap themselves: Each new word makes subsequent words easier to learn.

Language, thus, isn’t simply information transmission. It’s a tool for coordinating mental states, for aligning what we attend to, value, and believe.

Why Humans and Not Other Species?

Nonhuman apes have limited joint attention capacities and correspondingly limited symbolic abilities. Humans evolved uniquely strong joint attention and motivations to share experiences cooperatively.[9]

Many animals use meaningful signals, some acquiring limited symbol-like associations. But human symbolic systems are uniquely flexible, generative, and cumulative.

One reason is that human brains evolved unusually dense connectivity between systems involved in perception, emotion, memory, and action. This allows words and symbols to activate rich networks of associations rather than triggering narrow responses. This brain architecture also shapes language itself. As Christiansen and Chater emphasize, languages evolve to fit human learning and processing constraints, persisting because they are relatively easy to acquire, remember, and predict. Symbolic meaning thus reflects both general cognitive constraints and cultural evolution.[10]

Another reason is cultural accumulation. Language allows meanings to be stored and refined outside individual brains, in traditions, practices, and institutions.

Conscious Evaluation and the Evolution of Signals

But consciousness itself—not just human consciousness—may have transformed evolution long before symbolic language emerged. As Jablonka and Ginsburg argue, once animals could consciously perceive and evaluate composite patterns, mental selection began to shape the evolution of signals. The complexity of those signals depends on selection pressures arising from conscious interpreters.[11] One well-known example in evolutionary biology is the peacock’s tail. The extravagant beauty of the tail is plausibly explained by peahens’ ability to discriminate subtle pattern differences and to experience preferences. Because traits such as the peacock’s tail function as signals to others, these composite signals are strongly shaped by selection pressures arising from conscious evaluation (in this case, by peahens). This suggests that consciousness plays a role in the evolution of communication.[11]

These same evaluative capacities likely later shaped communicative signals, not just ornamental traits. This helps explain the sophistication of animal communication even without symbolic language. With symbolic language, however, mental selection itself changed in character: Instead of selecting only which signals to produce, humans began selecting meanings themselves—for clarity, precision, and even beauty in expression. Consciousness enabled signals; symbols made meanings the objects of deliberate refinement.

From Neural Meaning to Social Symbols

The transformation from individual neural meanings to shared symbolic meanings fundamentally changes what meaning can do. In sum, human symbolic meaning depends on shared intentionality—the capacity to establish joint goals, coordinate attention, and participate in socially shared conventions.[12]

This social grounding enables symbols to be preserved, refined across generations, and combined systematically. Unlike animal communication, which rarely accumulates, human symbolic meaning ratchets upward: Each generation builds on what came before.[13]

But symbols don’t just enable better communication. They transform the very nature of human existence. In Part 4, we’ll explore how shared symbolic meanings create cultural institutions with real causal power and personal narratives that give individual lives coherence, identity, and existential significance.

References

1. Eva Jablonka and Simona Ginsburg, “Learning and the Evolution of Conscious Agents,” Biosemiotics 15, no. 3 (2022): 401–437, https://doi.org/10.1007/s12304-022-09501-y

2. Douglas R. Hofstadter and Emmanuel Sander, Surfaces and Essences: Analogy as the Fuel and Fire of Thinking (New York: Basic Books, 2013). I explored examples of analogy-making in Hofstadter and Sander’s book in my post "What Actually Is a Thought? And How Is Information Physical?" https://www.psychologytoday.com/us/blog/finding-purpose/201902/what-act…

3. Stevan Harnad, “The Symbol Grounding Problem,” Physica D 42, nos. 1–3 (1990): 335–346, https://doi.org/10.1016/0167-2789(90)90087-6

4. Lawrence W. Barsalou, “Grounded Cognition,” Annual Review of Psychology 59 (2008): 617–645, https://doi.org/10.1146/annurev.psych.59.103006.093639

5. J. Kevin O’Regan and Alva Noë, “A Sensorimotor Account of Vision and Visual Consciousness,” Behavioral and Brain Sciences 24, no. 5 (2001): 939–973 (plus discussion), https://doi.org/10.1017/S0140525X01000115

6. Lawrence W. Barsalou, “Perceptual Symbol Systems,” Behavioral and Brain Sciences 22, no. 4 (1999): 577–660, https://doi.org/10.1017/S0140525X99002149

7. Douglas R. Hofstadter, Gödel, Escher, Bach: An Eternal Golden Braid, 20th anniversary ed. (New York: Basic Books, 1999), P-3. Originally published 1979.

8. Malinda Carpenter, Katherine Nagell, Michael Tomasello, George Butterworth, and Chris Moore, Social Cognition, Joint Attention, and Communicative Competence from 9 to 15 Months of Age, Monographs of the Society for Research in Child Development 63, no. 4 (1998): 1–174, https://doi.org/10.2307/1166214

9. Michael Tomasello, “Joint Attention as Social Cognition,” in Joint Attention: Its Origins and Role in Development, ed. Chris Moore and Philip J. Dunham (Hillsdale, NJ: Erlbaum, 1995), 103–130.

10. Morten H. Christiansen and Nick Chater, “Language as Shaped by the Brain,” Behavioral and Brain Sciences 31, no. 5 (2008): 489–558, https://doi.org/10.1017/S0140525X08004998

11. Eva Jablonka and Simona Ginsburg, “Consciousness: Its Goals, Its Functions and the Emergence of a New Category of Selection,” Philosophical Transactions of the Royal Society B 380 (2025): art. 20240310, https://doi.org/10.1098/rstb.2024.0310

12. Michael Tomasello, Malinda Carpenter, Josep Call, Tanya Behne, and Henrike Moll, “Understanding and Sharing Intentions: The Origins of Cultural Cognition,” Behavioral and Brain Sciences 28, no. 5 (2005): 675–735, https://doi.org/10.1017/S0140525X05000129

13. Hannes Rakoczy, Felix Warneken, and Michael Tomasello, “The Sources of Normativity: Young Children’s Awareness of the Normative Structure of Games,” Developmental Psychology 44, no. 3 (2008): 875–881, https://doi.org/10.1037/0012-1649.44.3.875; Claudio Tennie, Josep Call, and Michael Tomasello, “Ratcheting up the Ratchet: On the Evolution of Cumulative Culture,” Philosophical Transactions of the Royal Society B 364, no. 1528 (2009): 2405–2415, https://doi.org/10.1098/rstb.2009.0052