Age of acquisition and frequency of occurrence: Implications for experience based models of word processing and sentence parsing

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Age of acquisition and frequency of occurrence
Implications for experience based models of word
processing and sentence parsing

• Marc Brysbaert

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A rare phenomenon inpsychological research

• All researchers agree
• that word recognition depends on word
  frequency.
• High-frequency words are recognised faster than
  low-frequency words.

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Frequency effectin sentence parsing?

• More controversial
• Is sentence parsing based on principles or on
  experience?
• Examples of experience-based accounts tuning
  hypothesis, probabilistic models, neural networks
• This talk is on lexical processing, but the
  principles also apply to experience-based models
  of sentence processing.

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How do we measureword frequemcy?

• Word frequency is the frequency (per million)
  with which words are encountered in a
  representative corpus of text or (more recently)
  speech.
• As it happens, virtually all corpora are based on
  texts written and read or spoken by adults.

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Assumptions

• Either frequency of words in adulthood
  frequency of words in childhood
• or only words encountered in the last years matter

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Testing the assumptions

• Frequency childhood adulthood?
• ambulance adults 15 / million
• children 86 / million
• ancestor adults 15 / million
• children lt 1 / million
• It does not matter?
• Morrison Ellis (1995) words like ambulance
  are named 30 ms faster than words like ancestor
  (effect of 80 ms in LDT)

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Gerhand Barry (1999)
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The AoA effectdefinition

• Stimuli (words) that have been acquired early are
  processed faster than stimuli that have been
  acquired later, even when they are matched on
  frequency.
• AoA measured with rating scales or by directly
  looking at the performance of children (r .75).

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The AoA effectexplanations

• Three classes of explanations
• 1. Frequency and AoA have a different origin
• frequency effect strong at input stages AoA
  effect strong at verbal output stages
• effect of AoA in the organisation of the semantic
  system
• 2. Frequency and AoA have the same origin
• cumulative frequency instead of frequency
• learning in a connectionist model with
  distributed representations (loss of plasticity)

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The AoA effectexplanations

• Three classes of explanations
• 1. Frequency and AoA have a different origin
• 2. Frequency and AoA have the same origin
• 3. Effects of AoA are due to bad frequency
  measures
• Higher correlation with frequency when measures
  take into account childhood frequencies (Zeno et
  al.)
• Higher correlation with frequency when measures
  are based on film subtitles than on books (New et
  al., 2007)

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The AoA effectexplanations

• Brysbaert Ghyselinck (Visual Cognition, 2006)
• to decide between the first two classes, we have
  to look at the correlation between the frequency
  effects and the AoA effects across tasks
• if both effects have the same origin, there
  should be strong positive correlation between the
  magnitudes of the effects
• if the effect of AoA is due to cumulative
  frequency, then AoA lt freq

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Why the effect of AoA lt the effect of frequency
according to the cum hyp

• High frequency word gt 50 / million
• Low frequency word lt 5 / million
• This gives a ratio gt 101
• Early acquired words lt 5 yr (15 yrs ago)
• Late acquired words gt 15 yr (5 yrs ago)
• This gives a ratio of 31
• So, effect AoA 1/3 effect frequency

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Gerhand Barry (1998,1999a,b)
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Ghyselinck et al. (2004)
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Interim summary

• For many tasks, there is perfect correlation
  between the frequency effect and the AoA effect.
• This suggests that both effects are the result of
  the same learning process (futile to look for
  tasks that would show a frequency effect but no
  AoA effect).
• The AoA effect is too big for the cumulative
  frequency hypothesis.

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The connectionist account of AoA

• Ellis Lambon-Ralph (2000)
• Simple network 100 input nodes, fully connected
  to 50 hidden nodes, fully connected to 100 output
  nodes
•  Words  defined by arbitrary patterns of 0
  (80) and 1 (20)
• Groups of  words  entered at different times.

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Discussion with Zevin Seidenberg (2002)

• ZS an AoA effect that is larger than predicted
  on the basis of the cumulative frequency
  hypothesis will be found only when there is an
  arbitray mapping between input and output.
• Otherwise, the late-acquired patterns profit from
  the connections made by the early acquired
  patterns (is the case for word naming).

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Recapitulation claimBrysbaert Ghyselinck, 2006

• if the AoA and the frequency effect have the same
  origin, there should be strong positive
  correlation between the magnitudes of the effects

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In search of the frequency-independent AoA effect
in picture naming

• 1. Semantic origin of AoA
• Brysbaert et al. (2000) picture naming requires
  semantic mediation hence semantic origin of the
  frequency-independent AoA effect.
• Steyvers Tenenbaum (2005) growing network

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In search of the frequency-independent AoA effect

• problem no evidence for a frequency-independent
  AoA effect in semantic decision tasks (there is
  an AoA effect in these tasks, but it looks like
  it is the frequency-related AoA effect)

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In search of the frequency-independent AoA effect

• 2. The lexical-semantic competition hypothesis
• the frequency-independent effect is due to the
  transition from semantics to verbal output
• when we name a picture, initially many
  semantically related names (lemmas) become
  activated, and selecting the correct name
  requires a competition between the different
  candidates
• hypothesis early acquired lemmas are stronger
  competitors than late acquired lemmas (e.g., CAT
  is a stronger competitor for the naming of LION
  than vice versa)

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Belke et al. (2005)

• Made use of the semantic blocking effect.
• It is more difficult to name pictures repeatedly
  if they are part of a semantically homogeneous
  set than if they are part of a semantically
  heterogeneous set.

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Homogeneous condition
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Heterogeneous condition
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Belke et al. (2005)

• On the basis of the previous finding, we
  predicted that the blocking effect would be
  larger for late acquired words than for early
  acquired words

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experiment

• 36 participants
• 16 pictures with early-acquired names and 16
  pictures with late-acquired names
• matched on visual similarity, frequency, name
  length,
• stimuli presented 6 times per block
• homogeneous and heterogeneous lists in different
  blocks (counterbalanced)

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Early acquired stimuli
orange banana pear carrot lion frog
spider rabbit scissors paintbrush
ladder hammer jumper trousers dress shoe
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Late acquired stimuli
pepper cherry onion lettuce ostrich eagle beetle
camel chisel pliers spanner broom tights shaw
l mitten waistcoat
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In search of the frequency-independent AoA effect

• 3. Picture naming is not always semantically
  mediated
• Funnell et al. (2006)
• There is a difference in learning experience
  between young and old children.
• Young children learn about things by seeing them
  (either in real or in pictures).
• Older children learn about things by having them
  described

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In search of the frequency-independent AoA effect

• Funnell et al.
• Pictures of early acquired objects are named
  faster, because there is a direct link between
  the input stimulus and the name.
• Pictures of late acquired objects are named
  slower, because the naming requires semantic
  mediation

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Conclusions

• AoA as part of the cumulative frequency seems to
  be a given.
• Question whether AoA has an effect over and above
  cumulative frequency looks probable (plasticity
  in model)
• Still uncertainty about what causes the
  frequency-independent AoA effect in picture
  naming

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Reading list

• Brysbaert, M. Ghyselinck, M. (2006). The effect
  of age of acquisition Partly frequency related,
  partly frequency independent. Visual Cognition,
  13, 992-1011.
• Johnston, R.A. Barry, C. (2006). Age of
  acquisition and lexical processing. Visual
  Cognition, 13, 789-845.
• Juhasz, B.J. (2005). Age-of-acquisition effects
  in word and picture identification. Psychological
  Bulletin, 131, 684-712.