564 Reading
Rayner, 1985; Binder, Pollatsek, & Rayner, 1999; Inhoff,
1984; Rayner, Binder, Ashby, & Pollatsek, 2001; Rayner &
Well, 1996; Schustack, Ehrlich, & Rayner, 1987).
Before moving on, we should clarify what we mean when
we talk about predictability.In the studies we discuss in this
section, predictability is generally assessed by presenting a
group of readers with a sentence fragment up to, but not in-
cluding, the potential target word. They are then asked to
guess what the next word in the sentence might be. In most
experiments, a target word is operationally defined as pre-
dictable if more than 70% of the readers are able to guess the
target word based on prior sentence context, and unpre-
dictable if fewer than 5% of the readers are able to guess the
target word. We should note that during this norming process,
readers generally take up to several seconds to formulate a
guess, whereas during natural reading, readers only fixate
each word in the text for about 250 ms. This makes it unlikely
that predictability effects in normal silent reading are due to
such a conscious guessing process. Moreover, most readers’
introspection is that they are rarely if ever guessing what
the next word will be as they read a passage of text. Hence,
although we talk about predictability extensively in this
section, we are certainly not claiming the effects are due to
conscious prediction. They may be due to something like an
unconscious process that is somewhat like prediction, al-
though it would likely be quite different from conscious
prediction.
Although these predictability effects on skipping rates
are quite clear, there is some controversy as to the nature of
these effects. One possibility is that contextual influences
take place relatively early on during processing and, as such,
affect the ease of processing a word (i.e., lexical access). An
alternative view is that contextual influences affect later
stages of word processing, such as the time it takes to inte-
grate the word into ongoing discourse structures (i.e., text in-
tegration). One stumbling block in resolving this issue is that
some evidence suggests that fixation time on a word is at
least in part affected by higher level text integration process-
ing. For example, O’Brien, Shank, Myers, and Rayner (1988)
constructed three different versions of a passage that con-
tained one of three potential phrases early in the passage
(e.g.,stabbed her with his weapon, stabbed her with his knife,
orassaulted her with his weapon). When the word knifeap-
peared later in the passage, readers’ fixation times on knife
were equivalent for stabbed her with his weaponandstabbed
her with his knife,presumably because readers had inferred
when reading the former phrase that the weapon was a knife
(i.e., it is unlikely that someone would be stabbed with a
gun). In contrast, when the earlier phrase was assaulted her
with his weapon,fixation durations on the later appearance
ofknifewere longer. That is, in this last case, the fixation
duration on knifereflected not only the time to understand the
literal meaning of the word, but also to infer that the previ-
ously mentioned weapon was a knife.
Thus, a major question about these effects of predictability
is whether the effect occurs because the manipulation actu-
ally modulates the extraction of visual information in the ini-
tial encoding of the word, or whether the unpredictable word
is harder to integrate into the sentence context, just asknifeis
harder to process in the above example if it is not clear from
prior context that the murder weapon is a knife. Balota et al.
(1985) examined this question by looking at the joint effects
of predictability of a target word and the availability of the vi-
sual information of the target word. Participants were given
two versions of a sentence—one that was highly predictable
from prior sentence context or one that was not predictable
(e.g.,Since the wedding day was today, the baker rushed the
weddingcake/piesto the reception). The availability of visual
information was manipulated by changing the parafoveal pre-
view. Prior to when a reader’s eyes crossed a boundary in the
text (e.g., theninwedding), the parafoveal preview letter
string was either identical to the target (e.g.,cakeforcakeand
piesforpies), visually similar to the target (cahcforcakeand
piczforpies), identical to the alternative word (piesforcake
and vice versa), or visually similar to the alternative word
(piczforcakeandcahcforpies). The results replicated earlier
findings that predictable words are skipped more often than
are unpredictable words, but more importantly, visually sim-
ilar previews facilitated fixation times on predictable words
more than on unpredictable words. Moreover, there was a dif-
ference in the preview benefit forcakeandcahc,but there
was no difference in the benefit forpiesandpicz,so that read-
ers were able to extract more visual information (i.e., ending
letters) from a wider region of the parafovea when the target
was predictable as compared to unpredictable. The fact that
predictability interacts with these visual variables indicates
that at least part of the effect of predictability is on initial en-
coding processes. If it merely had an effect after the word was
identified, one would have no reason to expect it to interact
with these orthographic variables.Resolution of AmbiguityThe studies we have discussed up to this point clearly show
that there are powerful effects of context on word identifica-
tion in reading. However, they don’t make clear what level or
levels of word identification are influencing the progress of
the eyes through the text. For example, virtually all the phe-
nomena discussed so far could merely be reflecting the iden-
tification of the orthographic or phonological form of a word.