Bipolar Essay Example For Students

Bipolar Essay AbstractPrevious research suggests a significant difference in word recognition time between the left and right visual fields, with word recognition and response time of the right visual field significantly faster than the left visual field. The current study investigated bilateral visual fields on word recognition time by means of an online computer program consisting of 55 participants. It was hypothesized that men would respond faster than women, and the right visual field reaction times would be faster than the left. Results indicate that sex had no significant effect on reaction time. However, words presented in the right visual field were responded to significantly faster than words in the left. Supporting previous findings of a right visual (left hemispheric) advantage. The Effect of Bilateral Visual Fields on Word RecognitionWhen examining word recognition, there are a variety of factors that come into play. These factors include the role each hemisphere plays in terms of lan guage processing as well as the physiology of the brain. Further, when examining word recognition one must further understand the assortment of variables that come into play when dealing with word recognition. These include, but are not limited to the handedness of participants in word recognition studies, the type of words that are being studies (for example words of differing length, commonly used words versus less commonly used words), the manner by which participants are attending to the stimuli that are being presented, and the manner that words are presented. Understanding the role that each hemisphere of the brain plays in recognizing words, and the physiology of the brain is fundamental to the understanding of studies of word recognition. A primary tenet of neuropsychology is that the left hemisphere specializes in language, and language processing, while the right hemisphere plays less of a role in the processing of language (Grimshaw, 1998, Nicholls Wood, 1998). It should also be noted that stimuli presented to the right visual field has direct access to the left hemisphere, while information presented to the left visual field must first go to the right hemisphere, cross the corpus callosum, and then be interpreted in the left hemisphere (Grimshaw, 1998, Nicholls Wood, 1998). Because each hemisphere of the brain specializes in its own functions, one hypothesis is that the corpus callosum acts as a shield between hemispheres (Grimshaw, 1998). This hypothesis provides formal reasoning for the generally lowered reaction times that is often encountered when stimuli are presented to the left visual field (Nicholls, Wood, 1998). HandednessPrevious research has indicating the importance of handedness (which hand individuals prefer to use on typical everyday tasks) in word recognition. Research has indicated that cerebral lateralization plays a contributing factor in the processing of language. Specifically research has suggested that left handed individuals have weaker cerebral lateralization, thus the typical right visual field advantage that is shown in right handed individuals is not as predominant, and occasionally a left visual field advantage is seen in left handed individuals (Nicholls Wood, 1998). In a study conducted by Leventhal (1988) the role that cerebral dominance plays on the participants ability to recognize words were examined. The participants consisted of both left and right handed undergraduate students. The participants were presented words to the left visual field and the right visual field that were either emotionally neutral or emotionally stimulating. Previous word recognition studies have found that prosody is generally influenced by the right hemisphere, while language is processed in the left hemisphere (Grimshaw, 1998). Leventhal (1988) found that participants who were right-handed recognized more words presented in the right visual field than the left visual field, while left-handed participants recognized more words presented in the left visual field than the right. Overall, right-handed participants recognized more words than left-handed participants. Leventhal (1988) concluded that all participants were equally capable of recognizing words, but that a significant difference was found in reaction time between right-handed and left-handed participants. Handedness obviously plays an integral role in determining reaction time in word recognition tasks. The primary question that is presented upon reviewing the research available is why this occurs. If the left hemisphere always dictates language processing, why is it that left handed individuals occasionally show more rapid word recognition when stimuli are presented to the left visual field? Research has suggested that left handed individuals experi ence weaker brain lateralization, which could pose a feasible answer to this dilemma (Nicholls, ; Wood, 1998). AttentionThe effect that visual cues play on the role of word recognition is another variable that must be taken into account when examining word recognition. There have been studies that suggest that the right visual field has an advantage over the left visual field because words presented in the right visual field enjoy enhanced retinal attention versus stimuli presented in the left visual field (Batt, Underwood, ; Bryden, 1995). As such a variety of studies have been developed to divert attention from the right visual field to the left in order to change the area of retinal attention from what is thought to be the right to the left, in order to determine if this retinal attention may play a role in word recognition. Nicholls and Wood (1998) conducted a series of experiments to assess the contribution of attentional mechanisms to the right visual field advantage for word recognition. In the experiment the participants were presented with visual cues that were valid, invalid, or neutral. A valid cue was a cue that was shown in the same visual field as the stimulus was presented. Invalid cues were presented in the opposite visual field than the field that words are presented. Cues that were considered neutral were presented to both visual fields at the same time. Results of the experiments indicated words presented to the right visual field were likely to have lower levels of error in identification, as well as faster reaction times. The cueing effect discussed earlier was stronger for the left visual field than for the right visual field, which indicates that the left hemisphere requires less attention to process words. The right visual field advantage appears to reflect the left hemispheres enhanced capacity for processing verbal information. The asymmetrical effect of the cue suggests that attention does play an important role in perceptual asymmetries. A similar study performed by Lindell and Nicholls (2003) which examined the effect of cue position on hemispheric performance. This study also found that cue position had no effect on left hemisphere performance, suggesting that the right visual field enjoys an attentional advantage. Reaction times for word identification were faster and with fewer errors in response to words in the right visual field than the left visual field (Lindell Nicholls, 2003). Lindell and Nicholls (2003) also found that the right hemisphere showed a faciliatory effect of beginning cue, drawing spatial attention to the initial letter cluster, which enables efficient implementation of the right hemispheres sequential strategy. Proverbio, Zani, and Avella (1997) investigated hemispheric specialization for spatial frequency processing by measuring reaction times to sinusoidal gratings in 12 healthy subjects. Results showed that reaction times were significantly faster in the left visual field than the right visual field for low frequency gratings and faster in the right visual field than the left visual field for high frequency gratings. Proverbio et al. (1997) found overall reaction times were faster to high frequency gratings, and also found a significant interaction between frequency and visual field. Proverbios (1997) results show that reaction times to targets in a selective attention task differ as a function of spatial frequency and visual field stimulation. These results indicate a hemispheric specialization for the ability to identify low versus high spatial frequency in a selective attention task (Proverbio et al., 1997). Word PresentationResearch has shown that a visual field difference exists in word recognition, with words presented in the right visual field processed more quickly and accurately than words presented in the left visual field (Eviatar, Ibrahim, Ganayim, 2004; Iacoboni Zaidel, 1996; Jordan Patching, 2000; Leventhal 1988; Lindell Nicholls, 2003). Words have been found to be processed more quickly when presented in the right visual field rather than the left visual field because for most people visual word recognition is achieved by neural mechanisms situated in the left hemisphere (Farid Grainger, 1996). Iacoboni and Zaidel (1996) compared behavioral laterality effect in a lexical decision making task using cued unilateral and bilateral presentations of different stimuli to right-handed undergraduate students. Words were found to be processed more quickly than nonwords in both visual fields, but words produce more accurate responses in the right visual field. Bilateral presentatio ns were found to increase hemispheric independence in word recognition, with a bilateral presentation showing a word advantage in the right visual field and a nonword advantage in the left visual field (Iacoboni Zaidel, 1996). Unilateral presentations showed a significant word advantage in the right visual field, but no significant differences in the left visual field. Overall, unilateral presentation produced more accurate and faster responses than bilateral presentation. High frequency words were recognized with more accuracy than low frequency words, wordness and word length interaction was found. Iacoboni Zaidels (1996) hypothesis that after an initial similar perceptual process, words and nonwords are processed by independent, parallel processes was supported by the results of their study. Jordan ; Patching (2000) studied the bilateral presentation of words in the left and right visual field, as well as nonlaterally. Nonlateral words were shown centrally to stimulate particip ants reaction to words presented in the right and left visual field, similar to a fixation point. These nonlateral words were incorporated to alter the perception of the words located in the left and right visual fields. Participants were rated on their accuracy to correctly recognize words that were presented simultaneously as the nonlateral word. These words were given a perceived identity of the actual word being presented in the left or right visual field. For example, romp and ramp were presented to the participant at the same time, and the participant was asked to recognize the word not presented in the center of the screen. Participants were able to more accurately report words on the right visual field. However, participants responded to words in the left visual field more problematically. Jordan and Patchings (2000) findings also suggests that right visual field words frequently altered the perceived identity of the left visual field. To Kill A Mockingbird Essay SummaryMethodParticipantsA convenient sample of 55 (29 women and 26 men, age range 11 to 60) volunteered to participate in the current study. Six participants were left handed, 47 were right handed, and 2 were ambidextrous, as determined by self report. Participants included Christopher Newport University students, Christopher Newport University alumni, friends, and relatives of the experimenters. Participants were not compensated for their participation. All participants were treated in accordance with the Ethical Principles of Psychologists and Code of Conduct (American Psychological Association, 1992). MaterialsParticipants used their own computer that was connected to the internet in order to participate in the study. To begin this study, participants must download the necessary plug-in indicated as to have the appropriate system requirements: http://www.macromedia.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveAuthorware;P5_Language=English. The website used to run the experiment is located at: http://psychexps.olemiss.edu/Exps/Word_Recognition/startwr.htm PsychExperiments is an online social and cognitive psychology laboratory, developed by funding from the U.S. Department of Educations FIPSE program. The site consists of a variety of interactive experiments, a collective data archive, and downloadable support for materials that both participants and experimenters can use to gather data. Both sites can only be visited by a computer that is connected to the internet. In the current experiment, all data was collected using the PsychExperiments website. ProcedureEach participant accessed the website featuring the current experiment individually at a time convenient for them. Participants were given sufficient instructions (in either the form of email or printed out directions) about how to access the experiment. The experiment was accessed at psychexps.olemiss.edu. Participants were instructed to click on participate in experiments, located on the top left portion of the page. From there, participants were instructed to download the plug-in (located on the left side of the screen) necessary to install the program experiment on the participants computer. Then participants clicked on Lab Experiments, also located on the left side of the page. After that, participants were told to choose Word Recognition Study, and then to Run Word Recognition Study. Once the experiment was accessed, a description about the experiment and instructions on how to proceed were given by the program to participants. Participants were then given the option of participati ng. Participants who chose to participate then selected the appropriate region and project affiliationin the current study, participants were instructed to select the region including Virginia for their region, and Velkeys Project One as their affiliation. After this, demographical data (including age, sex, and hand preference) was collected before the actual experiment began. Once the experiment began, a total of 16 words were presented to each participant, with an indeterminate amount of trials because the experiment continued until the participant correctly identified all 16 words. To start each trial, the participant was prompted to press any key. To assure central fixation, a pulsating plus sign appeared in the beginning of the screen at the beginning of each trial. The pulsating plus sign stayed on the screen for 3-5 seconds and then a word was presented in either the left or right visual field, and then removed. The length of the time the word was presented depended on the number of times the word had been presented before. The participant was then prompted to type the word they saw flash on the screen. Once a word was correctly identified, it was removed from the words being presented. If the word was incorrectly identified, it was randomly presented again later in the experiment for a longer period of time. The experiment continued until all words had been correctly identified. ResultsThe position of words presented on the screen had a statistically significant effect on reaction time, F(1,53) = 17.654, p ; .001, h = .25. Participants mean recognition time for words presented on the left side of the screen .119 s, (SEM = .003). The mean recognition time for words presented on the right side of the screen was .108 s, (SEM = .002) (see figure 1). These results supported the experimenters hypothesis that words presented in the right visual field would be recognized more quickly than words in the left visual field. There was no statistical significance found to suggest an interaction between position of words presented on sex of participants, F(1, 53) = 1.552, p = .218, h = .028. Further, no statistical significance was found to suggest that sex had an effect, F(1, 53) = .271, p = .605, h = .005. These results failed to support the hypothesis of the experimenters that males would display a mean recognition time that was more quickly than females. DiscussionResults of the current study support the researchers hypothesis that words presented in the right visual field were recognized more quickly than words presented in the left visual field. These findings are consistent with previous research indicating a right visual field advantage. Several limitations were present in the current study. The convenient sample used in the current study was not representative of the population. In addition, not enough left-handed participants were included to study a handedness effect on word recognition. Previous research indicates that handedness has a significant effect on word recognition. Studies have shown that right-handed individuals have a stronger right visual field advantage than left-handed individuals because of weaker cerebral lateralization (Nicholls Wood, 1998); some studies have even found left handed individuals exhibiting a left visual field advantage (Leventhal, 1988; Nicholls Wood, 1998). Another problem which arose in the current study was accessing the project website. Many participants had problems downloading the required software plug-in in order to complete the experiment affecting the sample. The current study expands upon existing literature in the field of cerebral lateralization by reproducing previ ous findings indicating a right visual field advantage in word recognition (Batt et al., 1995; Iacoboni Zaidel, 1996; Leventhal, 1988; Jordan Patching, 2000; Nicholls Wood, 1998). Words presented in the right visual field were recognized more quickly overall than words presented in the left visual field. 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