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A W Inhoff

Publications and source records attributed to A W Inhoff.

31 records · Page 2Linked to original sources
PubMed1989

Probe-detection times during the reading of easy and difficult text.

Two experiments were conducted to determine the effects of text difficulty on cognitive capacity demands. In Experiment 1, subjects read easy and difficult text when a secondary task was either present or absent. Text was presented one word at a time, and rereading was prevented by erasing each word after it had been read. Prior studies have indicated that cognitive capacity demands decrease as text difficulty increases (e.g., Britton, Westbrook, & Holdredge, 1978). In contrast to this, the main results of Experiment 1 revealed shorter visual-probe-detection times during the reading of easy text than during the reading of difficult text. Analyses of word-reading times showed that difficult text was read slower than easy text, irrespective of probe application. Experiment 2 compared visual-probe detection with auditory-probe detection. The results again showed shorter probe reaction times during the reading of easy text than during the reading of difficult text, irrespective of probe type. There were, however, effects of probe type on the reading time of words following the visual probe. The results were taken as evidence that the reading of difficult text requires more capacity than the reading of easy text and that probes may incur modality-specific and modality-independent capacity demands.

Adult↗
PubMed1989

Covert attention and eye movements during reading.

Eye movements were monitored during the reading of spatially transformed text in order to examine covert attentional processes in reading. In some conditions, the sequence of letters within a word was congruent with (i.e. in the same direction as) the sequence of words in the sentence; in other conditions the direction of letters within words and the direction of words in the sentence were incongruent. In addition, the window of visible text was varied so that in some conditions only the fixated word (and all preceding words) were visible, whereas in other conditions the fixated word and the succeeding word were both visible. Readers were able to extract more parafoveal information from text when the words themselves were normal than when the letters within the words were transformed. However, with practice, readers were able to use some parafoveal information even when the words were transformed. The most important finding was that the congruity of the word and letter order had no reliable effect on the ability to extract parafoveal information and influenced reading performance only when the words themselves were normal. We conclude that covert attention in reading is not a letter-by-letter scan that sweeps across the page, but either an asymmetric spotlight held constant on each fixation or a shifting of an attentional spotlight extending across multiletter units (possibly words) with the direction of shifts of attention closely coupled to the direction of eye movements.

Attention↗
PubMed1989

The role of cerebellar structures in the execution of serial movements.

Thirteen patients with bilateral cerebellar disease and 12 patients with unilateral cerebellar disease were instructed to execute movement sequences in response to a simple reaction signal. Each to-be-executed sequence consisted either of a single, two, or three keypress components. Evidence for cerebellar involvement in the execution of programmed responses was sought in the pattern of response onset times and interkeypress times. Patients with mild bilateral cerebellar dysfunction or mild unilateral dysfunction, and neurologically unimpaired subjects showed increases in response onset time as sequence length increased from L = 1 to L = 3. In contrast to this, there were negligible or no effects of sequence length on response onset time in patients with moderate bilateral cerebellar dysfunction and in patients with moderate unilateral cerebellar dysfunction who responded with the hand ipsilateral to the lesion. Furthermore, cerebellar dysfunction was associated with significantly slower interkeypress reaction times. These results support the hypothesis that the translation of a programmed sequence of responses into action involves cerebellar structures which schedule a sequence of ordered responses before onset of movement.

Adult↗
PubMed1988

Orienting of visual attention in progressive supranuclear palsy.

Orienting of visual attention was studied in 8 patients with progressive supranuclear palsy (PSP) and 8 parkinsonian control subjects. While maintaining fixation on the centre of a visual display, subjects made simple reaction time (RT) key press responses on detecting visual targets which appeared above, below, to the left or right, equidistant from fixation. On each trial the target was preceded by a preparatory cue, either a peripheral luminance change or a central arrow, to summon attention to one of the four locations. The orienting of attention was measured as a facilitation in detection RT at the cued location. For the parkinsonian controls, this facilitation was equal for horizontal and vertical directions, whereas for both types of cues, PSP patients were slower moving attention in the vertical than in the horizontal plane. Midbrain retinotectal pathways are important not only for controlling eye movements, but also for orienting attention.

Aged↗
PubMed1987

Programming and execution of sequential movements in Parkinson's disease.

In separate blocks of a simple reaction time (RT) task, eight Parkinsonian and eight control subjects executed finger press sequences with one (index finger), two (index finger-ring) or three (index finger-ring-middle) components. Programming was inferred from the increase latency to initiate the first component as a function of the length of the entire sequence; and from the systematic decrease in inter-response latencies for the second and third components. Overall RT was slower in the Parkinsonians but the programming effects were comparable in the two groups. Intact basal ganglia function appears not to be necessary for programming sequential finger movements, or retrieving subprograms for execution.

Adult↗
PubMed1985

The effect of factivity on lexical retrieval and postlexical processes during eye fixations in reading.

Subjects were required to read short passages of text while their eye movements were monitored. Each experimental passage contained a critical factive or nonfactive verb that was followed by a false complement. In half of the trials, subjects' reading was unimpaired; in the remainder of the trial, a central visual pattern mask, which moved in synchrony with the eyes, was applied. The results showed that (1) factive and nonfactive verbs did not receive different amounts of fixation time during the reading text. However, (2) false complements that followed nonfactive verbs. On the basis of this, it is concluded that individual word characteristics, such as factivity, are encoded automatically while sentence interpretation requires effort to be completed.

Eye Movements↗
PubMed1985

Lexical access during eye fixations in reading: effects of word-initial letter sequence.

Two experiments tested the hypothesis that lexical access in reading is initiated on the basis of word-initial letter information obtainable in the parafoveal region. Eye movements were monitored while college students read sentences containing target words whose initial trigram (Experiment 1) or bigram (Experiment 2) imposed either a high or a low degree of constraint in the lexicon. In contradiction to our hypothesis, high-constraint words (e.g., DWARF) received longer fixations than did low-constraint words (e.g., CLOWN), despite the fact that high-constraint words have an initial letter sequence shared by few other words in the lexicon. Moreover, a comparison of fixation times in viewing conditions with and without parafoveal letter information showed that the amount of decrease in target fixation time due to prior parafoveal availability was the same for high-constraint and low-constraint targets. We concluded that increased familiarity of word-initial letter sequence is beneficial to lexical access and that familiarity affects the efficiency of foveal but not parafoveal processing.

Fixation, Ocular↗
PubMed1982

Parafoveal word perception: a further case against semantic preprocessing.

Three experiments were performed to explore the processing of parafoveal information. A foveal and a parafoveal word pair were presented within the time frame of a single fixation, but short enough to prevent successful refixation of the parafoveal word. Subjects reporting partial parafoveal word information were not able to use this information to bias their choice in a forced-choice task requiring some semantic information from the parafoveal word for correct performance. This result was observed even though correct parafoveal word identification was facilitated if the foveal stimulus was related to the parafoveal word. Further, the data strongly suggest that information is obtained initially from the fixated words, regardless of whether foveal word presentation precedes or follows the parafoveal stimulus.

Discrimination Learning↗
PubMed1981

Masking of foveal and parafoveal vision during eye fixations in reading.

A window or visual mask as moved across text in synchrony with the reader's eye movements. The size of the window or mask was varied so that either information in foveal or parafoveal vision was masked on each fixation. In another experiment, the onset of the mask was delayed for a certain amount of time following the end of the saccade. The results of the experiments point out the relative importance of foveal and parafoveal vision for reading and further indicate that most of the visual information necessary for reading can be acquired during the first 50 msec that information is available during an eye fixation.

Adult↗