Mixing Memory

Picture in your head one person throwing a ball to another. How were the two people oriented spatially? Was one on the left, and the other on the right? If so, which one was on the left, and which on the right? Chances are, the thrower was on the left, and the catcher was on the right. For some reason, that seems to be our default way of representing actions: with the actor on the right, the patient on the left, and the actions occurring from left to right(1), as in this beautifully drawn figure:

i-cec68a4cf0423b7ddb3e92c5c78fd3d8-ballthrow.JPG

Why is that? Good question, but before we answer it, let’s look at some research.

The most striking work on the relationship between language and the spatial representation of actions has been done by Chatterjee and his colleagues. They first looked at the relationship in a patient with profound agrammatism, an aphasia that makes it difficult to put grammatical sentences together. Here’s an example of their agrrammatic aphasic’s speech(2, p. 58):

Well, uh, essentially language abandon preposition. I telegraph… I, I… consciously, uh, continuity…I, I, uh, this subtle of prepositional phrases this simply cannot do. Under stress, under stress rapid I just flustered … but continue to do basically.

As you can see, it’s a mess. When they had this aphasic identify the agents and patients in pictures, he almost always said that the figure on the left was the agent, and the one on the right was the patient, regardless of which one was actually the agent and the patient in the figure(3).

Interesting, but this could be the product of the aphasia right? What about people with normal speech and comprehension abilities? To answer this question, Chatterjee et al.(4) conducted a series of studies with non-aphasic participants. In their first study, they had participants (all right-handed) read one of three types of sentences: an action by a patient in the direction of the patient (e.g., “John pushes Tom”), an action by an agent towards the agent and away from the patient (“John pulls Tom”), or a state requiring an agent and a patient (“John likes Tom”). Participants were then asked to draw the events on a piece of paper. In almost all cases, participants drew the agents on the left and patients on the right for each type of sentence, with drawings of the first type (action moving from agent towards the patient, as in “John pushes Tom”) tending to represent the agent the furthest to the left relative to the patient.

In their second experiment, they had participants draw actions that occurred on either a horizontal (e.g., “staggering drunk”) or vertical (e.g., “falling book”) axis. The vertical actions were used as a control. For the horizontal actions, participants drew 8 out of 10 moving from left to right, on average. Here are a couple example drawings, from their Figure 1 (p. 398):

i-af8178ee74b2d3afe32cfa9b97867f66-chaterjeeetal1999Fig1.jpg

In their third experiment, Chatterjee et al. had participants listen to sentences, after which they were presented with figures that either represented the actions in the sentences (e.g., “Square pushes Circle,” with a picture of a square-headed stick figure pushing a circle-headed stick figure). The sentences either involved actions moving from the actor to the patient (like pushing) or from the patient to the agent (like pulling). Half of the pictures presented the agent on the left and the patient on the right. The participants were told to indicate as quickly as they could (by pressing the right or left mouse buttons) whether the picture represented the action in the sentence they’d just heard. Overall, participants were faster to indicate whether the picture represented the sentence when the agent was on the left and the patient on the right.

So there’s good evidence that we represent actors on the left and agents on the right, and tend to think of actions as occurring from left to right. But why? Chatterjee et al. argue that this is because our representations of actions have an inherent spatial component, and that this is due to the way our nervous system is organized. They write:

The left to right directional bias is likely to be linked to the neural encoding of events[ Both cerebral hemispheres deploy spatial attention with vectors in opposing directions[ The left hemisphere deploys spatial attention with a vector from left to right. As previously speculated, development of languagein the left hemisphere may have coopted left hemisphere spatial attentional networks opportunistically. An overlap of neural circuits mediating spatial attention, the directional representations of events and the instantiation of verbs, may provide the neural link between the spatial and propositional representation of events. (p. 401)

However, recent evidence argues against this explanation. Several studies have shown that adults who learned to write in a right-to-left writing system (as in Hebrew), as opposed to left-to-right (as in English), tend to put agents on the right and patients on the left, with actions tending to be represented as moving from right to left. In other words, the inherent spatial aspect of action representations could be a product of the writing system we use, rather than the wiring of our brain.

To test this hypothesis directly, Dobel et al.(5) used preschoolers who hadn’t yet learned to write, and adults who could, in Germany (left-to-right writing) and Israel (right-to-left writing) as participants. Each participant (child and adult) heard sentences containing an actor, patient, and object (e.g., “The mother gives the boy a ball”), and for half of the sentences, drew it on a piece of paper, and for the other half, arranged three transparencies (one with the object, one with the actor, and one with the patient) so that they depicted the action.

In both tasks, the children showed no bias, placing the agents to the left and right of the patients equally often. The adults, however, did show a bias, with the Hebrew-speaking adults placing the agent on the right about 60% of the time, and the German-speaking adults placing the agent on the left side about 60% of the time. The fact that the children who couldn’t write didn’t show the bias, while adults educated in left-to-right and right-to-left writing systems showed opposite, language-consistent biases in agent placement strongly suggests that it is as a result of our writing system, and not the innate wiring of the brain, that our action representations are inherently spatial.


1Chatterjee A. (2001). Language and space: some interactions. Trends in Cognitive Science, 5, 55-61.
2Ibid.
3Chatterjee A., Maher, L.M., Gonzalez-Rothi, L.J., & Heilman, K.M. (1995) Asyntactic thematic role assignment: The use of a temporal-spatial strategy. Brain and Language, 1995, 49, 125-139.
4Chatterjee, A., Southwood, M.H., & Basilico, D. (1999). Verbs, events and spatial representations. Neuropsychologia,37, 395-402.
5Dobel, C., Diesendruck, G., & Bölte, J. (2007). How writing system and age influence spatial representation of actions. Psychological Science, 18(6), 487-491.

Comments

  1. #1 Tim
    June 25, 2007

    “In other words, the inherent spatial aspect of action representations could be a product of the writing system we use, rather than the wiring of our brain.”

    Not to nitpick, but clearly the writing system we use affects the wiring of our brain. So both explanations could be (and probably are) correct.

  2. #2 Chris
    June 25, 2007

    Tim, yeah, I should have included the word “innate,” as I did in the last sentence.

  3. #3 Jake
    June 25, 2007

    Interesting. But what if the sentences were written passively, with the actor on the right and the patient on the left, e.g. Tom was pushed by John? It could be that the order of the subjects in the sentence plays a role in the order of the subjects in the picture. This idea doesn’t hold up too well against “staggering drunk,” but I think it’s still worth considering.

  4. #4 Chris
    June 25, 2007

    Jake, Chatterjee has looked at sentences like that, and the results are the same.

  5. #5 ME
    June 25, 2007

    So I wonder how this extends to up-down writing systems — perhaps the reason why those are less popular is because actions tend to take place horizontally?

    Also, does this imply that somewhere in the brain, a sentence is actually visualized as a sort of cartoon, such as the one in the article, and then converted into a sentence in the order that it is written?

  6. #6 Chris
    June 26, 2007

    Well, if Chatterjee’s hypothesis were correct, it would imply some sort of image-based representation. The fact that the writing system influences the representation of events, however, is more difficult to interpret in terms of representation.

  7. #7 Kutsuwamushi
    June 26, 2007

    ME, I think that historical factors would get in the way of ever answering the question of whether or not we’re predisposed to write horizontally–at least by looking at the percentages of horizontal vs. vertical writing systems.

    The Roman, Greek, and Cyrillic alphabets are related, as are many of the writing systems used in South and Southeast Asia, for example. Some writing systems that were (mostly) original inventions, like Glagolitic and Cree, were invented by people who were exposed to a certain type of writing. And so on.

  8. #8 yitz..
    June 26, 2007

    When I started reading the article .. I pictured right to left, not left to right. What’s weird about that is that english is my native reading/writing/speaking language, but I emigrated to Israel 7 years ago, and have been working on hebrew as my second language, reading/writing/speaking it. (I did learn (some) hebrew in highschool and dayschool growing up, but certainly not with the same intensity with which I used/learned english.)

    Which means that either the wiring in my brain has changed significantly over the past seven years (which is surprising because i still write/read more (on average) english than hebrew) or it has less to do with the “wiring” and more to do with the ‘frame of mind’ or readiness to understand. (I’ve spent a lot of time honing my scanning ability in hebrew to be as good as it is in english)

  9. #9 max hodges
    June 26, 2007

    Probably related to the same mental structures which cause a tendency for languages to be either predominantly left-branching or right-branching. How about tying this down in sociobiological terms, to epigenetic rules encoded in neurobiology and ultimately to the genes themselves?

    “Both cerebral hemispheres deploy spatial attention with vectors in opposing directions” = Scientists feigning understanding with deployed gooblygook.

  10. #10 Abel
    June 27, 2007

    Hasn’t this been show before with:

    1991 Tversky, B., Kugelmass, S., & Winter, A. (1991).Cross-cultural and developmental trends in graphic productions. Cognitive Psychology, 23, 515-557.

    ?

  11. #11 Eve
    June 27, 2007

    “For some reason, that seems to be our default way of representing actions: with the actor on the right, the patient on the left, and the actions occurring from left to right(1), as in this beautifully drawn figure:”

    Is the first part there the right way around?

    Thanks for posting about this!

  12. #12 Xepher
    July 6, 2007

    So, when I first pictured the scenario (as asked in the first sentence) I saw over the head of the one throwing the ball, and the catcher was directly downfield from him. There was no left/right at all. What does that mean? :-) Surely, in all those tests, someone drew or described their answer from that perspective. (FYI, I’m right handed and read/write only in English.) Does that indicate some “balance” between the left/right options, or maybe it has something to do with having a background in engineering-esque stuff, including 3D animation… that I’m used to picturing stuff in perspective, not flat. As such, my “answer” has nothing at all to do with language. No idea, just guessing. I’m always curious about our varying perceptions of the world.

  13. #13 lee durham stone
    April 24, 2008

    Then perhaps a good research project might be to study illiterate people to see how they represent the action.

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