Garvin Chastain
Biographic Data
| ID | 5853969 |
|---|---|
| NAME | Garvin Chastain |
| GIVEN NAMES | Garvin |
| FAMILY NAME | Chastain |
| SIGNATURE | CHASTAIN G |
| AFFILIATIONS | Boise State University |
| VERIFIED | No |
| TOTAL WORKS | 21 |
| TOTAL CITATIONS | 3 |
| WORKS AS AUTHOR | 21 |
| WORKS AS EDITOR | 0 |
| FIRST PUBLICATION YEAR | 1983 |
| LATEST PUBLICATION YEAR | 2006 |
| H-INDEX | 1 |
Alcohol, Neurotransmitter Systems, and Behavior
Alcohol affects several neurotransmitter systems within the brain. In this article, the author describes its effects on 5 major ones: glutamate, gamma-amino-butyric acid (GABA), dopamine, serotonin, and opioid systems. The author also notes the interactions and interdependencies of these transmitters, and provides details on both immediate effects and long-term adaptations. Last, the author explains several psychopharmacological treatments for al…
Attention Effects of Abrupt-Onset Precues with Central, Single-Element, and Multiple-Element Precues
Inhibition of Return
Inhibition of return (IOR), first described in 1984, was considered to be a general phenomenon for ensuring that attention would be allocated to successive stimuli in the environment. In the present research, IOR was expressed in forced-choice identification tasks with either reaction time or accuracy as the dependent measure. Thus, the generality of IOR was supported, because response inhibition cannot explain IOR found with accuracy measures. C…
Facilitatory or Inhibitory Nontarget Effects in the Location-Cuing Paradigm
Duration Ratings as an Index of Processing Resources Required for Cognitive Tasks
Six experiments provided tests of the effectiveness of subjective duration ratings as an index of the processing resources required in cognitive tasks. Duration ratings reflected significant differences between the resources needed to process high- and low-frequency words (Experiments 1, 5, and 6), and ambiguous and unambiguous words (Experiments 1 and 2), and produced an interaction between memory load and word frequency (Experiment 6). However,…
An Analysis of Reicher-Task Effects
Three experiments conducted to investigate aspects of the word-nonword version of the Reicher task were motivated, in part, by the recent series of experiments by Prinzmetal (1992). He found a word-superiority effect (WSE) with unlimited exposure durations, in contrast to the typical Reicher-task method involving limited exposures, raising the issue of whether lexical access is involved in the WSE with brief exposures. An interactive-activation a…
Experiment Spot-Checks
R. Eric Landrum, Garvin Chastain, Experiment Spot-Checks: A Method for Assessing the Educational Value of Undergraduate Participation in Research, IRB: Ethics & Human Research, Vol. 17, No. 4 (Jul. - Aug., 1995), p. 4
Mood and Lexical Access of Positive, Negative, and Neutral Words
Two experiments based upon the Reicher task were conducted to investigate the influence of happy, sad, and neutral moods on the processing of positive, negative, and neutral words. In Experiment 1 participants showed least advantage in determining which of two one-letter-different words, in comparison with nonword controls, had been presented for words that were valenced in congruence with the induced mood. In Experiment 2 mood acted as a prime t…
Letter Detection in Multiple-Meaning Words
The methodology of Reicher (1969) was used to perform three experiments to determine whether the number of word meanings has an effect on letter-detection performance. Performance was hypothesized to be superior on multiple-meaning words (i.e., ambiguous words such as bank) than on single-meaning words (i.e., unambiguous words such as cause), because ambiguous words may possess a separate lexical entry for each distinct meaning. Results from each…
Time-Course of Sensitivity Changes as Attention Shifts to an Unpredictable Location
Shifting visual attention is often described as analogous to a spotlight moving through empty space between locations. In the present experiment, a peripheral precue summoned attention to an initial location, and 200 ms later a second peripheral cue appeared beside one of two possible second locations, each 14 degrees away from the initial location. The target was twice as likely to appear at the location that had been indicated by the immediatel…
Effects of Abruptly Appearing Clutter on a Peripherally Precued Covert Attention Shift
The effects of clutter that appears abruptly with the target during covert shifts of attention to a precued target location in the visual field were studied. The delay between the appearance of the precue and that of the target with clutter was varied within each block. Blocked conditions included clutter density, the similarity between the shape of the clutter character and that of the target, and whether a clutter character appeared in each pat…
Representation of Letters When Mislocation Errors Occur
Errors in reporting a cued target letter appearing among a string of letters more often reflect the mislocation of a letter appearing elsewhere in the string than the intrusion of one not in the string. The current experiment was conducted to determine the representation of letters at the stage at which errors occur. Four letters (from a set of 12 chosen to contain counterpart pairs that were similar physically, phonemically, or both physically a…
When Shape Information from a Foveal Nontarget Affects Gap Detection Accuracy in a Parafoveal Target
Effects on gap detection accuracy of information at fixation concerning a parafoveally presented target form's global shape were determined in three experiments. Shape information was not directly relevant to the correct response regarding the presence of the gap. Tests were conducted to determine whether costs and benefits were associated with shape information, whether the effectiveness of shape information was sensitive to spatial attention, a…
Does order of Letter Analysis Contribute to the Parafoveal Identification Asymmetry
A parafoveally presented target character usually is identified more accurately when flanked by a nontarget character to its foveal side than when flanked by one to its peripheral side. An outside-in process of analysis produced by uncertainty about the target's position could contribute to this asymmetry. Current results revealed a greater asymmetry with relative target position blocked than with it mixed over trials, suggesting that target posi…
Target Letter Inclusion in Single and Multiple Word Substrings and Identification Accuracy
In experiment 1, target letter discrimination in quadrigrams containing multiple subwords was found to be no more accurate than target letter discrimination in strings of four unrelated letters. Discrimination in quadrigrams, each including the target letter and a one-word trigram of which the target was not a part, was significantly poorer than discrimination in either of the other two types. In Experiment 2, a possible explanation of the latter…
Visually-Presented Letter Strings Typically are Encoded Phonologically
Three experiments were conducted to show that phonological encoding is typical for visually-presented letter strings, and that an interactive activation model with a phonological route to the mental lexicon accounts adequately for the word-superiority effect. In Experiment 1, pseudohomophones produced a word-superiority effect that was as great as that produced by words. More accurate target discrimination in homophones than in nonhomophones in E…
Facilitation in Letter Detection with Sequentially Presented Homophonic Strings
A consistent phonology between sequentially presented pseudoword quadrigrams was found to improve performance in a letter-detection task. Each of 8 subjects was required to judge whether an M appeared in either the initial or terminal position of letter strings. The letter N was used as a foil. For each presentation, two quadrigrams appeared sequentially, the first for 20 ms and the second for a duration that allowed approximately 75% overall acc…
Phonological Recoding in Letter Detection
Access to the mental lexicon through a phonological code derived from visually presented strings of letters was demonstrated by feedback from lexical entries enhancing the perceptibility of letters in the strings. The task required judging whether each of a number of briefly presented quadrigrams contained a D in the initial or terminal position. Four sets of four quadrigrams per set were used, with one pair in each set being phonologically simil…
Phonological Access to the Mental Lexicon in a Target Discrimination Task
A phonological route to the mental lexicon was demonstrated in two experiments. Each involved a target discrimination task in which the target was the first or last letter of a quadrigram. Half the quadrigrams were pseudohomophones (identical in sound but not in spelling to an English word) and the other half were nonhomophones (pronounceable but neither spelled like nor sounding like any English word). In Experiment 1 each pseudohomophone had a …
Report-Order Inversions
Report-order inversions for two parafoveally presented stimuli were examined by presenting the pair members side by side or one above the other. Regardless of whether the pair appeared above, below, to the left of, or to the right of fixation, inversions predominated when members were presented side by side. Instead of stemming from feature mislocalizations which sometimes place distinctive features from the more peripheral figure to the foveal s…
Parafoveal Identification Asymmetry is a Lateral Masking Effect
The degree to which the identification of a parafoveally presented letter target was impaired by being flanked by a foveal or peripheral nontarget at a target-mask interval of zero, 75, or 150 msec, was examined. Peripheral placement of the nontarget was more disruptive than foveal placement, and this asymmetry was significantly more pronounced at a 75-msec interval than at either of the other two. This finding is consonant with explanations of t…
Phonological Access to the Mental Lexicon in a Target Discrimination Task
A phonological route to the mental lexicon was demonstrated in two experiments. Each involved a target discrimination task in which the target was the first or last letter of a quadrigram. Half the quadrigrams were pseudohomophones (identical in sound but not in spelling to an English word) and the other half were nonhomophones (pronounceable but neither spelled like nor sounding like any English word). In Experiment 1 each pseudohomophone had a …
Duration Ratings as an Index of Processing Resources Required for Cognitive Tasks
Six experiments provided tests of the effectiveness of subjective duration ratings as an index of the processing resources required in cognitive tasks. Duration ratings reflected significant differences between the resources needed to process high- and low-frequency words (Experiments 1, 5, and 6), and ambiguous and unambiguous words (Experiments 1 and 2), and produced an interaction between memory load and word frequency (Experiment 6). However,…
Report-Order Inversions
Report-order inversions for two parafoveally presented stimuli were examined by presenting the pair members side by side or one above the other. Regardless of whether the pair appeared above, below, to the left of, or to the right of fixation, inversions predominated when members were presented side by side. Instead of stemming from feature mislocalizations which sometimes place distinctive features from the more peripheral figure to the foveal s…
Parafoveal Identification Asymmetry is a Lateral Masking Effect
The degree to which the identification of a parafoveally presented letter target was impaired by being flanked by a foveal or peripheral nontarget at a target-mask interval of zero, 75, or 150 msec, was examined. Peripheral placement of the nontarget was more disruptive than foveal placement, and this asymmetry was significantly more pronounced at a 75-msec interval than at either of the other two. This finding is consonant with explanations of t…
Phonological Access to the Mental Lexicon in a Target Discrimination Task
A phonological route to the mental lexicon was demonstrated in two experiments. Each involved a target discrimination task in which the target was the first or last letter of a quadrigram. Half the quadrigrams were pseudohomophones (identical in sound but not in spelling to an English word) and the other half were nonhomophones (pronounceable but neither spelled like nor sounding like any English word). In Experiment 1 each pseudohomophone had a …
Phonological Recoding in Letter Detection
Access to the mental lexicon through a phonological code derived from visually presented strings of letters was demonstrated by feedback from lexical entries enhancing the perceptibility of letters in the strings. The task required judging whether each of a number of briefly presented quadrigrams contained a D in the initial or terminal position. Four sets of four quadrigrams per set were used, with one pair in each set being phonologically simil…
Facilitation in Letter Detection with Sequentially Presented Homophonic Strings
A consistent phonology between sequentially presented pseudoword quadrigrams was found to improve performance in a letter-detection task. Each of 8 subjects was required to judge whether an M appeared in either the initial or terminal position of letter strings. The letter N was used as a foil. For each presentation, two quadrigrams appeared sequentially, the first for 20 ms and the second for a duration that allowed approximately 75% overall acc…
Visually-Presented Letter Strings Typically are Encoded Phonologically
Three experiments were conducted to show that phonological encoding is typical for visually-presented letter strings, and that an interactive activation model with a phonological route to the mental lexicon accounts adequately for the word-superiority effect. In Experiment 1, pseudohomophones produced a word-superiority effect that was as great as that produced by words. More accurate target discrimination in homophones than in nonhomophones in E…
Does order of Letter Analysis Contribute to the Parafoveal Identification Asymmetry
A parafoveally presented target character usually is identified more accurately when flanked by a nontarget character to its foveal side than when flanked by one to its peripheral side. An outside-in process of analysis produced by uncertainty about the target's position could contribute to this asymmetry. Current results revealed a greater asymmetry with relative target position blocked than with it mixed over trials, suggesting that target posi…
Target Letter Inclusion in Single and Multiple Word Substrings and Identification Accuracy
In experiment 1, target letter discrimination in quadrigrams containing multiple subwords was found to be no more accurate than target letter discrimination in strings of four unrelated letters. Discrimination in quadrigrams, each including the target letter and a one-word trigram of which the target was not a part, was significantly poorer than discrimination in either of the other two types. In Experiment 2, a possible explanation of the latter…
When Shape Information from a Foveal Nontarget Affects Gap Detection Accuracy in a Parafoveal Target
Effects on gap detection accuracy of information at fixation concerning a parafoveally presented target form's global shape were determined in three experiments. Shape information was not directly relevant to the correct response regarding the presence of the gap. Tests were conducted to determine whether costs and benefits were associated with shape information, whether the effectiveness of shape information was sensitive to spatial attention, a…
Representation of Letters When Mislocation Errors Occur
Errors in reporting a cued target letter appearing among a string of letters more often reflect the mislocation of a letter appearing elsewhere in the string than the intrusion of one not in the string. The current experiment was conducted to determine the representation of letters at the stage at which errors occur. Four letters (from a set of 12 chosen to contain counterpart pairs that were similar physically, phonemically, or both physically a…
Effects of Abruptly Appearing Clutter on a Peripherally Precued Covert Attention Shift
The effects of clutter that appears abruptly with the target during covert shifts of attention to a precued target location in the visual field were studied. The delay between the appearance of the precue and that of the target with clutter was varied within each block. Blocked conditions included clutter density, the similarity between the shape of the clutter character and that of the target, and whether a clutter character appeared in each pat…
Time-Course of Sensitivity Changes as Attention Shifts to an Unpredictable Location
Shifting visual attention is often described as analogous to a spotlight moving through empty space between locations. In the present experiment, a peripheral precue summoned attention to an initial location, and 200 ms later a second peripheral cue appeared beside one of two possible second locations, each 14 degrees away from the initial location. The target was twice as likely to appear at the location that had been indicated by the immediatel…
Letter Detection in Multiple-Meaning Words
The methodology of Reicher (1969) was used to perform three experiments to determine whether the number of word meanings has an effect on letter-detection performance. Performance was hypothesized to be superior on multiple-meaning words (i.e., ambiguous words such as bank) than on single-meaning words (i.e., unambiguous words such as cause), because ambiguous words may possess a separate lexical entry for each distinct meaning. Results from each…
Experiment Spot-Checks
R. Eric Landrum, Garvin Chastain, Experiment Spot-Checks: A Method for Assessing the Educational Value of Undergraduate Participation in Research, IRB: Ethics & Human Research, Vol. 17, No. 4 (Jul. - Aug., 1995), p. 4
Mood and Lexical Access of Positive, Negative, and Neutral Words
Two experiments based upon the Reicher task were conducted to investigate the influence of happy, sad, and neutral moods on the processing of positive, negative, and neutral words. In Experiment 1 participants showed least advantage in determining which of two one-letter-different words, in comparison with nonword controls, had been presented for words that were valenced in congruence with the induced mood. In Experiment 2 mood acted as a prime t…
Facilitatory or Inhibitory Nontarget Effects in the Location-Cuing Paradigm
Duration Ratings as an Index of Processing Resources Required for Cognitive Tasks
Six experiments provided tests of the effectiveness of subjective duration ratings as an index of the processing resources required in cognitive tasks. Duration ratings reflected significant differences between the resources needed to process high- and low-frequency words (Experiments 1, 5, and 6), and ambiguous and unambiguous words (Experiments 1 and 2), and produced an interaction between memory load and word frequency (Experiment 6). However,…
An Analysis of Reicher-Task Effects
Three experiments conducted to investigate aspects of the word-nonword version of the Reicher task were motivated, in part, by the recent series of experiments by Prinzmetal (1992). He found a word-superiority effect (WSE) with unlimited exposure durations, in contrast to the typical Reicher-task method involving limited exposures, raising the issue of whether lexical access is involved in the WSE with brief exposures. An interactive-activation a…
Attention Effects of Abrupt-Onset Precues with Central, Single-Element, and Multiple-Element Precues
Inhibition of Return
Inhibition of return (IOR), first described in 1984, was considered to be a general phenomenon for ensuring that attention would be allocated to successive stimuli in the environment. In the present research, IOR was expressed in forced-choice identification tasks with either reaction time or accuracy as the dependent measure. Thus, the generality of IOR was supported, because response inhibition cannot explain IOR found with accuracy measures. C…
Alcohol, Neurotransmitter Systems, and Behavior
Alcohol affects several neurotransmitter systems within the brain. In this article, the author describes its effects on 5 major ones: glutamate, gamma-amino-butyric acid (GABA), dopamine, serotonin, and opioid systems. The author also notes the interactions and interdependencies of these transmitters, and provides details on both immediate effects and long-term adaptations. Last, the author explains several psychopharmacological treatments for al…
Psychology (20 works) · Computer Science (15 works) · Reading and Literacy Development (10 works) · Linguistics (9 works) · Visual perception and processing mechanisms (9 works) · Medicine (8 works) · Neuroscience (8 works) · Natural language processing (7 works) · Neural and Behavioral Psychology Studies (7 works) · Audiology (6 works)