Wilson, “The case for sensorimotor coding in working memory”

1. Wilson, “The case for sensorimotor coding in working memory” Wilson’s thesis: Items held in short-term verbal memory are encoded in an “articulatory” format --in terms of the motor routines used to produce speech (but not fully executed) --or the forms used to produced signs, in the case of sign-language users

2. The Baddeley and Hitch Model of Short-Term Memory

3. Four Short-Term Memory Effects Phonological similarity: poor recall of similar sounding items Word length: longer items harder to remember Suppression: poor recall when articulatory mechanism is engaged in competing activity Irrelevant speech: poor recall with competing auditory input

4. Messy Interaction of Effects Articulatory suppression neutralizes the phonological similarity effect, but only if materials are presented in auditory form. Explanation: When stimulus items arrive in auditory form, they must be recoded by articulatory processes. When the items are delivered in print form, for example, they can be placed directly in the buffer without articulatory encoding.

5. Articulatory suppression neutralizes the word length effect regardless of the form of the stimulus items. This suggests that the word length effect is always the effect of an articulation process.

6. Word Length Effect and Sign Language Experiments with temporally long signs show a word length effect, even when number of sub-units is controlled for (and even when the shorter signs have more sub-units!). Deaf signers have shorter linguistic memory span than standard speakers. Individual signs have longer “articulation” times than typical words.

7. Evidence from Nonsigners --show a length effect when told to speak slowly --span for digits varies across languages with average length of digits (in terms of pronunciation time) (Chinese: shortest articulation time, largest span; English: intermediate in both respects; Welsh: longest articulation time, shortest digit span) --similar results (intrasubject) with bilinguals --within-language effect for comparison of vowel articulation times (‘harpoon’ v. ‘bishop’)

8. Constant relation: span divided by articulation time (approx. 2) Children who pronounce r’s as w’s systematically make related recall mistakes (‘wing’ v. ‘ring’) Wilson concludes that a (possibly innate) systems of linguistic encoding lies behind all of these effects.

9. Richardson et al. Preliminary study Two experiments: --choose the rebus sentence that most naturally reflects the meaning of a verb --generate image schemas corresponding to verbs --two sets of results show a significant item-by-item correlation between angles associated with verbs

11. Experiment one Hypothesis: non-specific imagery activated by verb comprehension will interfere with performance on a visual task if the imagery shares its axis with the visual task. Design: Subjects hear sentences through earphones. After brief, varied interval (50-200 ms), subjects must identify circle or square presented on either horizontal or vertical axis relative to fixation cross.

12. Results

13. Reaction times are slower when the circle or square to be identified fall along the same axis as the one associated with the verb in the preceding sentence. Difference is significant but appears to be due primarily to the effect of verb-type on the identification of test stimuli along the vertical axis.

14. Experiment 2 Study trials: Subjects hear sentences read while viewing sequentially presented pictures of the agent and patient (subject and object); all pictures are centrally located. Test trials: Two pictures are presented simultaneously in either horizontal or vertical alignment. Subjects must indicate whether the two pictures were associated with the same sentence during the study phase.

15. Results No effect of axis-based match or mismatch on accuracy or response; memory that two pictures were paired was high across the board. Reaction times showed interaction between verb orientation and stimulus orientation. In particular, accurate responses were significantly faster when the paired pictures were presented along the vertical axis and the vertical axis is associated with the verb in the relevant sentence.

17. Conclusion Linguistic meaning has some spatial component.

18. Spivey and Geng, PsychologicalResearch, 2001. Experiment 1: Subjects heard stories with a directional component while their eye movements were tracked. While listening to the stories, subjects’ eye movements tended to track the dynamics of the stories.

19. Experiment 2 Participants saw four shapes of varying color and orientation in four corners of a 3×3 grid. The screen went blank for a moment, and then only three of the shapes returned. Participants were asked a question about the orientation or color of the missing shape. Participants made a saccade to the blank location of the grid where the queried shape had once been, despite the fact that there was clearly no useful information present there.

20. Richardson and Spivey, “Representation, space and Hollywood Squares: looking at things that aren't there anymore,” Cognition, 2000. Reported similar findings to experiment 2, using a 4x4 grid. A talking head appears in only one cell (others are blank) and describes a brief sequence of events. Later, when subjects are asked about the events, they focus on the corresponding cell, even though the screen is blank.