Biomedical subjects

A W Inhoff

Publications and source records attributed to A W Inhoff.

At least 19 recordsLinked to original sources

PubMed2000

Is the processing of words during eye fixations in reading strictly serial?

Extant models of oculomotor control during reading maintain that allocation of attention confines word recognition to one (target) word at a time, and that an eye movement to a new (posttarget) word is computed before attention is shifted to it. To test these assumptions, properties of the posttarget's preview were manipulated during the fixation of the preceding target word. The main results revealed longer target viewing durations when the posttarget preview was visually distinctive or when it was orthographically illegal. The meaning of posttarget text did not affect initial target word reading, although it affected the time spent rereading the target. To account for these findings, extant attention-shift models must assume that readers obtain at least visuospatial and orthographic information from a parafovelly visible word before it is attended. This view has shortcomings, however, and several considerations favor less restrictive model assumptions according to which attention can be allocated to more than one word at a time.

Attention↗

PubMed1998

The perceptual span and oculomotor activity during the reading of Chinese sentences.

Eye-movement-contingent display changes were used to control the visibility of characters during the reading of Chinese text. Characters outside a window of legible text were masked by dissimilar characters, and effects of viewing constraints were ascertained in several oculomotor measures. The results revealed an asymmetric perceptual span that extended 1 character to the left of the fixated character and 3 characters to its right. The size of right-directed saccades extended across 2 to 2 1/2 character spaces, indicating that the perceptual spans of successive fixations overlapped slightly and that some linguistic information was integrated across fixations. The relatively small spatial overlap of successive spans appears to reflect a text-specific process. However, the results also revealed substantial similarities in the coding of morphographic Chinese and alphabetic English texts, indicating that text-specific coding routines are subordinated to general coding principles.

China↗

PubMed1996

Compound word effects differ in reading, on-line naming, and delayed naming tasks.

Bimorphemic compound words (e.g., blueberry), bimorphemic suffixed words (e.g., ceaseless), and monomorphemic controls (e.g., arthritis) were read in neutral sentence contexts in Experiment 1. The main result revealed longer first fixation durations on compound words than on control and suffixed words. Different effects emerged when naming tasks were used. An on-line naming task revealed substantially shorter naming latencies for compound words than for control and suffixed words. Naming latencies for compound and control words were equivalent in a delayed naming task. These results indicate that on-line naming latencies and word-viewing durations may yield diverging results. They also suggest that activation of constituent words of compound words occurs independently from the specification of conventional word meanings.

Adult↗

PubMed1995

Loss of vision during the retinal stabilization of letters.

Upper- and lower-case letters of the alphabet were stabilized until loss of vision occurred. Loss of straight-line visibility was the most frequently reported perceptual event. Occasionally, features of letters separated spatially before their loss of visibility. In both instances, loss of visibility often resulted in the perception of a less complex letter. Confidence ratings for each loss of letter visibility indicated that participants were quite certain about perceived fragmentations. In a control experiment, participants were asked to guess how letters would fragment during stabilization. Again, loss of line visibility was the most frequently reported event. However, spatial separation of features was rarely predicted and complex letters were not predicted to fragment into simpler letter forms. Furthermore, the confidence in predicted fragmentation was quite low. These results are consistent with the view that losses of visibility during retinal stabilization constitute a distinct perceptual experience. Fragmentations appear to be determined by the availability of less complex letter forms and by the loss of subletter information, consisting of letter features and information specifying spatial configurations.

Adult↗

PubMed1995

Mindless reading: eye-movement characteristics are similar in scanning letter strings and reading texts.

The purpose of the present study was to compare the oculomotor behavior of readers scanning meaningful and meaningless materials. Four conditions were used--a normal-text-reading control condition, and three experimental conditions in which the amount of linguistic processing was reduced, either by presenting the subjects with repeated letter strings or by asking the subjects to search for a target letter in texts or letter strings. The results show that global eye-movement characteristics (such as saccade size and fixation duration), as well as local characteristics (such as word-skipping rate, landing site, refixation probability, and refixation position), are very similar in the four conditions. The finding that the eyes are capable of generating an autonomous oculomotor scanning strategy in the absence of any linguistic information to process argues in favor of the idea that such predetermined oculomotor strategies might be an important determinant of eye movements in reading.

Attention↗

PubMed1994

Seeing morphemes: loss of visibility during the retinal stabilization of compound and pseudocompound words.

When stabilized, a retinal image fades from vision. Earlier studies suggested that knowledge constrains the loss of vision, as disappearing images fragment into familiar subpatterns. Effects of image stabilization on word perception were used in the current study to examine effects of morphemic knowledge on stimulus fragmentations. Bimorphemic compound words (in which beginning and ending trigrams formed morphemic subword units) and monomorphemic pseudo-compound words (with a similar trigram structure) were stabilized. Stimulus fragmentations generally resulted in the visibility of lexically nondistinct strings of letters. However, internal morpheme boundaries also affected the loss of vision when compound words were stabilized. Two follow-up experiments indicated that morpheme-related loss of vision was neither the result of differential forgetting rates nor of guessing bias.

Fixation, Ocular↗

PubMed1993

Attention demands during reading and the occurrence of brief (express) fixations.

Eye movements were recorded while subjects read passages of text repeatedly (Experiment 1) and while normal text and strings of homogeneous letters were fixated (Experiment 2). Text repetition decreased fixation durations and increased saccade size, presumably because it decreased attention demands. Irrespective of repetition, however, no distinct distribution of brief (express) fixations emerged. In Experiment 2, fixation durations were shorter and saccades were larger when strings of homogeneous letters were "read," indicating that this condition decreased attention demands. Again, however, no distinct distribution of express fixations emerged. These findings pose problems for the view that attentional processes determine the occurrence of brief (express) fixation durations in reading. Supplementary analyses of Experiments 1 and 2 suggested that visuospatial processing affected fixation durations, irrespective of linguistic processing demands.

Adolescent↗

PubMed1992

Saccade programming during short duration fixations: an examination of copy typing, letter detection, and reading.

Three experiments examined saccade programming during short duration fixations between 50 ms and 150 ms. In experiment 1, subjects copy typed text, in experiment 2, subjects read and executed a letter detection task, and in experiment 3, subjects read for comprehension only. Fixation duration had no effect on the size of the departing saccade in the copy typing task; however, saccades leaving short duration fixations were larger than saccades leaving all other fixation durations in the letter detection task and smaller than saccades leaving long fixation durations in the standard reading task. Within Morrison's (1984) model, these results imply, first, that consecutive shifts of attention during a fixation can take different directions and, second, that successive shifts of attention during a fixation support different purposes. Within Fischer's (1986, in press) model, the results imply that the engagement/disengagement of attention and saccade programming do not constitute independent events.

Adult↗

PubMed1992

Encoding of text, manual movement planning, and eye-hand coordination during copytyping.

Typing span and coordination of word viewing times with word typing times in copytyping were examined. In Experiment 1, typists copied passages of text while their eye movements were measured. Viewing location was determined during each eye fixation and was used to control the amount of usable visual information. Viewing constraints decreased interword saccade size when fewer than 7 character spaces of text were visible to the right of fixation and increased interkeypress times when fewer than 3 character spaces of text were visible. The eye-hand span amounted to 2.8 character spaces. Experiment 2 revealed increases in word typing times and word viewing times as biomechanic typing difficulty increased and word frequency decreased. These findings are consistent with a model of eye-hand coordination that postulates that eye-hand coordination involves central and peripheral processes.

Attention↗

PubMed1992

Eye-hand span and coding of text during copytyping.

Concurrent oculomotor and manual activities during copytyping were examined to determine whether (a) typists keep the eyes 1-s ahead of the executed keypress, (b) control of eye-hand (E-H) coordination follows the lexical representation of to-be-typed text, and (c) typists seek visual information beyond the boundaries of the fixated word. To-be-typed text contained high- and low-frequency target words that were either short or long. Two viewing conditions were used revealing either the directly fixated word only or the fixated word plus the next word in the text. The results showed no support for the 1-s E-H lag hypothesis. The E-H span was also not affected by the visibility of text but was a function of word frequency, suggesting that E-H coordination follows the lexical representation of text. Effects of window size indicated that typists seek visual information beyond the boundaries of the fixated word.

Adult↗

PubMed1992

Bimodal extinction without cross-modal extinction.

Three patients with unilateral neurological injury were clinically examined. All showed consistent unilateral extinction in the tactile and visual modalities on simultaneous intramodal stimulation. There was virtually no evidence for cross-modal extinction, however, so that contralateral stimulation of one modality would have extinguished perception of ipsilateral stimuli in the other modality. It is concluded that the attentional system controlling the encoding of tactile and visual stimuli is not unified across the two sensory domains.

Adult↗

PubMed1991

Word frequency during copytyping.

Two experiments examined effects of visual encoding and of manual motor programming during copytyping. In Experiment 1, expert typists copied sentences containing high- or low-frequency target words; instructions emphasized either the speed of typing or text comprehension. The results showed increased typing times for words preceding low frequency targets in the comprehension condition. However, pretarget typing was not affected by target frequency when speed of typing was emphasized, indicating that the visual encoding of text does not affect concurrent keypresses. Low-frequency words themselves were typed slower than high-frequency words. Supplementary analyses indicated that word frequency may affect the programming of a sequence of keystrokes forming a word. Consistent with this assessment, Experiment 2 showed that effects of word frequency cannot be reduced to movement practice.

Attention↗

PubMed1991

Semantic processing of unattended text during selective reading: how the eyes see it.

Subjects were instructed to read and comprehend a target (attended) passage while eye movements were recorded. A second (unattended) passage was also present, with attended and unattended passages occupying alternating lines of text. Subsequent multiple-choice questions showed acquisition of semantic information from attended and unattended text. However, a detailed examination of eye-fixation records showed that readers occasionally fixated unattended text, indicating the presence of shifts of visual attention to unattended text. When fixations of unattended text were excluded, there was no longer any indication that readers obtained useful semantic information from unattended text.

Attention↗

PubMed1990

Lexical integration across saccades in reading.

Eye movements were recorded during sentence reading to examine the integration of parafoveal text across fixations. Four viewing conditions were used, each affording full view of the directly fixated word: no preview of the spatially adjacent parafoveal word; preview of its beginning trigram; preview of its beginning four letters; or preview of all its constituent letters. The magnitude of parafoveal-preview benefits (the difference between the no-preview condition and the different parafoveal-preview conditions) was examined as a function of the size of the saccade to the parafoveal target and as a function of the subsequent fixation location at the previewed target. The results revealed no effects of saccade size on parafoveal-preview benefits, but large effects of fixation position during the initial target fixation. Furthermore, parafoveal previews were used during the initial target fixation and during subsequent intratarget refixations. The results support a lexical-text-integration hypothesis which posits that lexical information is integrated across interword fixations and intraword refixations.

Adult↗

PubMed1990

Integrating information across eye fixations in reading: the role of letter and word units.

Eye movements and eye fixations were recorded to study the integration of letter/word information across interword fixations in reading. Two hypotheses were examined. One hypothesis posits that readers obtain effective information from the beginning two or three letters of a parafoveal word. This information facilitates the recognition of the word when it is being fixated. The alternative posits that effective information is obtained from the complete parafoveal word. The results of the present study showed faster reading rates when parafoveal previews comprised complete words than when they comprised beginning letters alone. Furthermore, the usability of parafoveally available partial word information from beginning and ending letters was not affected by small variations in retinal eccentricity. Both findings were taken as evidence that readers gain useful information from all letters of the parafoveally available word and that whole word information, rather than specific letter information, is integrated across interword fixations in reading.

Adult↗

PubMed1990

Unimanual tapping during concurrent articulation: examining the role of cortical structures in the execution of programmed movement sequences.

Three experiments were conducted to examine effects of speech on concurrent unimanual tapping. Experiments 1 and 2 involved the manual tapping of a short burst of preprogrammed responses with or without concurrent articulation. Results of these experiments showed no effects of speech articulation on the concurrent execution of programmed manual movement sequences. In Experiment 3, subjects continuously tapped for 15 sec, again, with or without concurrent speech articulation. The results showed that articulation affected the speed of concurrent manual responses with larger interference for right hand tapping than for left hand tapping. Additional analysis of the tapping variability revealed equivalent effects of concurrent articulation on the timing of repetitive right and left hand tapping. Kinsbourne's Functional Cerebral Distance Principle was used to interpret these results. Within this framework, the present findings indicate that functionally distinct processes control speech articulation and the execution of programmed manual movement sequences.

Arousal↗

PubMed1990

Lexical priming from partial-word previews.

Two naming and two lexical decision experiments examined the use of partial-word preview in visual word recognition. Replicating results of an earlier reading study, the results of Experiments 1 and 2 revealed significant benefits from position-specific beginning- and ending-letter previews. Furthermore, benefits from beginning letters were greater for words than for pseudowords. Ending-letter previews showed no corresponding lexical superiority. Experiment 3 revealed that preview of position-specific letters from the beginning plus the ending part of target stimuli, which did not reveal a unique word-beginning letter sequence, facilitated the classification of words but not pseudowords. The results support a two-route model of lexical access in which some partial-word previews afford activation of specific lexical representations, and some partial-word previews afford activation of subword representations.

Adult↗

PubMed1989

Parafoveal processing of words and saccade computation during eye fixations in reading.

Studied parafoveal word processing during eye fixations in reading to answer two questions: (a) Is the processing of parafoveally available words limited to the identification of beginning letters? (b) Does the parafoveal processing of words affect the following interword saccade? Reading afforded either no parafoveal preview, preview of beginning trigrams, preview of ending trigrams, or preview of the whole parafoveal word. Previews were controlled by replacing original letters either with X's or dissimilar letters. Preview benefits were larger for the whole word previews than for beginning or ending trigram previews. X-masks yielded preview benefits from intact beginning and ending trigrams but dissimilar letter masks yielded benefits from beginning trigrams only. Saccades were larger for whole word previews than for no previews. These results support Logogen-type models of word recognition and a model of saccade computation that posits a time-locked functional relation between the acquisition of parafoveal word information and the positioning of each fixation.

Attention↗