The Origin of the Interocular Transfer that Leads to the Motion after Effect - Research Paper Example

Outline. Part 1. 1.0. Introduction 2.0. Discussion 2.1. Motion after effect 2.2. Experimentation 2.3. Findings 2.4. Significance of findings 3.0. Conclusion 4.0. Recommendations Part 2. 1.0. Introduction 2.0. Discussion 2.1. The serial position effect 2.2. Experimentation 2.3. Findings 2.4. Significance of findings 3.0. Conclusion 4.0. Recommendations Part 1. 1.0. Introduction. A number of scholars have debated the origin of the interocular transfer that leads to the motion after effect. This report focuses on the motion after effect and the effect on the adapted eye against the other that is not adapted. Besides, it roots for relationship between interocular transfer of an adapted eye and an un-adapted eye. Finally, it establishes the origin of the motion after effect. The report is arranged into five sections. The first section explains the concept of the motion after effect, the second explains the experiment conducted to this effect, the third section explains the findings highlighting the significance of the findings. The fourth part concludes the report, while the fifth offers recommendations for future studies. 2.0. Discussion 2.1. Motion after Effect. The motion after effect is experienced after viewing a dynamic object for some time. The illusion is created by a viewer whose eyes are stationary looking at a moving object. After viewing for a few minutes, the view becomes fixated, creating a fixated stationary stimulus. The stationary stimulus creates an illusion of a movement in the opposite direction from the original movement. This effect is assumed to be as a result of adaptation to motion. The motion after effect illusion can be created by a number of objects. The water fall effect, for instance, in created by a viewer looking at a water fall for some time, then instantly looking at a stationary object. The effect is that the stationary object seems to be moving upwards, in the opposite direction as the water fall. The spiral effect is yet another such illusion created by looking at rotating objects. The motion after effect is explained by the activity of neurons. Neurons are responsible for coding movements perceived by the human eye. When these movements are repeated for some time, the neurons reduce the amount of responses attributed to the movements: the neurons adapt to the movement and cease rapid responses. When this happens, the neurons are in a state of imbalance that has to be balanced for effective adaptation. This way, the neurons perceive stationary objects close to the moving object to be moving in the opposite direction. This counters the other movement, and a balance between the two is achieved. Varied suggestions have been put forward in an effort to explain the origin of the motion after effect. Some argue that it originates from the central part of the brain in the visual cortex, while some argue that it originates from the peripheral part in the retina. In order to ascertain true the origin, an experiment assessing the inter-ocular transfer was conducted (Glasser et al, 2011). 2.2. Experimentation. This experiment was conducted with the aim of finding out the origin of the motion after effect. It is testing the central (visual cortex) and the peripheral (retina) as the two possible origins. Working in pairs, one person looked at a swirling pattern on a computer for a minute with both eyes, and then with one eye at a time. After the one minute of viewing, the viewer looked at his partner’s face and recorded the time the motion after effect lasted. The other partner repeated the same process and they both recorded the time the motion after effect lasted. 2.3. Findings. The experiment was conducted of 136 participants, 34 males and 102 females. The motion after effect when closing each eye in turns was measured against the time the effect lasted and each recorded down. The effect was measured for the eye that was closed, and for the eye that remained open. The mean of difference for the two conditions when calculated was a positive 7.76. The standard deviation was also clustered around 6. The t-test showed a high degree of interdependence of motion after effect between the two eyes at 37% of the effect that is generated monocularly. The experiment indicates a clear presence of binocular cortical neurons that have similar effect on both eyes. This explains the reason why the different eye experienced motion after effect even when it was closed. This is explained by the interocular transfer effect. This refers to a change in perception of one eye that is occluded. The change is similar to, but of lower magnitude and effect than the eye that was open and fixated on a motion and responding to the stimulated vision. The after effect motion signifies that the there is total interocular transfer between eyes, and this process is not governed by the retinal activities, but the visual cortex. Binocular neurons converge on the primary visual cortex, enabling adaptation of the eyes to the motion, thus creating the after motion effect. 2.4. Significance of Findings. This experiment serves to strengthen earlier findings that showed correlations between interocular transfer and binocularity. Interocular transfer is, however, present in monocular cells even when the adapting stimulus is introduced for the other eye. The retina is highly unlikely to be the origin of such adaptation even if some form of adaptation is observed in the retina. This is because these adaptations do not have specific patterns of definite adaptation. In addition to this, more controversy over the relationship between interocular transfer and the binocular neurons is created because some monocular cells exhibit adaptation while some binocular cells do not. This, therefore, contradicts the assumption that the magnitude of after effects vision is directly proportional to the amount of neurons adapted to a given stimuli. The interocular transfer is, thus, assumed to be as a result of a response to the stimulus at the cortex. This fact, also explains the reason as to why humans who lack binocular neurons have been found to posses interocular transfer from the monocular neurons (Mather et al, 1998). The presence of adaptation in both binocular and monocular cells to a lesser extent indicates that the process of adaptation is not caused by mere fatigue due to the cells’ continued response to the moving stimulus. Adaptation is brings about tonic hyper polarization, whose strength depends upon the amount of stimulating stimulus. Tonic hyper polarization, in turn, affects response to any other stimulus the eye may be exposed to. This explains the experiments above where there was little effect on the specific eye exposed to the stimulus. Therefore, the amount of hyper polarity produced during the adaptation process is directly correlated to the magnitude of the interocular transfer. The strength of motion after effect is high in the adapted eye, standing at 73%. 76% of the effect is transferred to the un-adapted eye if the un-adapted eye viewed a filed similar to that the adapted eye viewed. The transfer reduced to around 50% if the un-adapted eye was occluded. 3.0. Conclusion. The experiments done above, supported by previous works on the same indicate that the motion after effect is higher in the adapted eye than the other. The other eye experiences a lesser effect of the motion, and to a large extent is biased by the observer’s prior knowledge of the motion. The interocular transfer is attributed to being responsible for the motion after effect experience, which in turn, is effected to a large extent by the binocular cells. Monocular cell, too play a role in the effect, though studies reveal that the role is smaller compared to that played by the binocular cells. The interocular transfer, which is responsible for the after motion effect is caused by the visual cortex and not by the retinal cells. This means that the after motion effect originates from the visual cortex. 4.0. Recommendations. The above experiment is highly inconclusive because of limited variance in the sample chosen. First, the number of females is too high compared to that of men. it is possible that males and females react differently in the after motion effect. It would be appropriate that the numbers of the two is balanced to give equal presentation. Concerns have been raised on the probability of the participants being affected by bias formations because of the prior knowledge of the existing motion. This could affect the un-adapted eye, reaction to the motion after effect. it would, therefore, be recommendable that the experiment uses children and animals with similar eye characteristics as humans. These will provide unbiased results are they are hardly aware of the expectations of the experiment to form bias. Part Two. 1.0. Introduction. Variations in ability to recall things and in the order that they are stated is one issue that has caught the interest of many scholars. People have been found to create certain patterns while recalling, which are in total opposite of that with which the things are mentioned. Suggestions have been put forward in an effort to explain these differences, and one such explanation is the serial position effect. This report shall explain the serial position effect, its influence and impact in the process of recalling, and gents responsible for the effect. We shall then refer to our experiments and seek possible explanation for the results, interpret the results, and examine their significance on the process of recalling. A conclusion and recommended tasks will then be outlined as deemed suitable for the study. 2.0. Discussion. 2.1. The Serial Position Effect. This term refers to the effect of accuracy to recall things as varying in relation to the position of the item or subject in the study. People, in normal conditions and situations often recall things from the last to first. This is called the recency effect. The first items have a better chance of being recalled than those in the middle, while the very last have the highest chances of being recalled. This is called the primacy effect. 2.2. Experiments. In the experiments performed, it emerges that participants were able to recall early the items named later in the list than those named earlier. Those Named earlier, however were recalled toward the end on the recalling list. The items that were most forgotten were those that were presented in the middle of the list. Some participants named items that were not in the presentation list, while a few repeated those that they had already named. The mean from the experiments stands at around 15, a standard deviation of 3, and a 33% rate of freedom. 2.3. Findings. From the experiments above, it is clear that the items mentioned last are the ones remembered first. This, as we said earlier is because of the primacy effect. The primacy effect is believed to be caused by, among many suggestions, by the possibility that items mentioned initially are stored up in the long-term section of the memory. This is because these items get the privilege of being allocated more levels of processing. These follow a sequence that the listener is able to recall the first item on a list by itself, the second alongside the first, the third alongside the second and first, and so on. Therefore, initial items require more time and processing power than subsequent items (Davelaar et al, 2005). The primacy effect is more effective when items are said slowly than fast. The process of processing and storing each item takes time, and so when the time is given in plenty, the process is well done, but when it is given in haste, the process is also done in haste, hence insufficient time to process and store the item in the permanent memory. Few items also get enough space in the memory and are likely to be stored up for longer than when the list of items is long. The length of the items will require more haste in saying out the list and they will jam the memory and will not be appropriately stored. The recency effect occurs when the items most recently pronounced are easily recalled than the earlier ones. One explanation for this is that these items have not yet been transferred to the permanent memory and are, therefore, easily retrieved and recalled than those in the permanent memory. The ability to recall recent items is, however, affected when the process is interrupted. Any such interruption will require the involvement of the working memory. This, if it lasts up to 30 seconds, is likely to cause disrupt the recency effect and even cancel out any such effect still in the brain. If no such interruption takes place, the recency effect is likely to hold up no matter the length of the list of items presented and the pace of presentation. This is explained by a theory. The dual store model postulates that there are two memory stores: the short-term and long-term memory stores. Solving an arithmetic problem as the ones presented to participants during the experiments above during the period of retention tampers with the short-term store. This is because the store has a smaller capacity and cannot handle the added process of calculation. The calculations, therefore, displace the previous list to the long-term store to give it room. Retrieving these items from the long-term store takes time, hence they lose their status are easily retrievable (Howard & Kahana, 2002). From the experiments, we can deduce that the primacy effect has more impact when the participants are given intervals between the presentations so that they are able to rehearse the previous list. We can also note that the recall is likely to be for an item neighbouring another in the serial position. This is called the continuity or lag-recency effect. 2.4. Significance of the Findings. These findings have proven to be important to the study and understanding of memory-related illnesses such as Alzheimer’s disease. The recency effect, for instance, is responsible for the condition among people with amnesia. These are only able to recall recent activities, meaning that only the short-term memory of their brain is active, while the permanent storage is not. That is why they cannot reproduce a list of initial items, but rather of the recent items only. Those with Alzheimer can only exhibit a low functioning and effectiveness of the primacy effect, but are not capable of producing the recency effect (Bailey et al, 2000). 3.0. Conclusion. The serial position effect explains the effect of recalling items that are arranged in a given pattern of a particular sequence. This effect is affected by two major factors: the primacy effect and the recency effect. the primacy effect enables items mentioned earlier in the list to be stored up in the permanent memory, hence retained, while the recency effect enables items mentioned later in the list to be stored in the short-term memory, hence recalled faster. The pattern of recalling is also affected by the pattern in which the items are arranged and follow each other in the presenting list. 4.0. Recommendations. Previous experiments have indicated that participants were aware that they would be needed to recall the items presented to them. They would, therefore, cram the items so that they would reproduce them easily. Such a situation distorts the experiment and does not give true results that are free from the human bias. To remedy this situation, it would be better that such an experiment be conducted among children who may not be aware of the requirements of the experiment, thus providing objective results. Besides, the experiment can be done on animals such as pets in the guise of giving instructions. They can be tested to identify which instructions they remember first, later, those they do not remember at all, and the effect of disrupting them while partaking the instructions. This will give more credence to the human experiments that face the threat of bias. Recent studies have found out that the primacy and recency effects do not exist in mutual exclusiveness, but rather co-exist to affect mixed effects in recalling. This concern needs more studies and experiments to ascertain its truth to enable making of more informed conclusions. Reference. Bayley, P. J., David P. S., Bondi, M. W., Bui, B. K., Olichney, J., Dean C. D., Thomas, R. G., & Thai, L. J. (2000). "Comparison of the Serial Position Effect in very Mild Alzheimer's Disease, Mild Alzheimer's Disease, and Amnesia associated with Electroconvulsive Therapy". Journal of the International Neuropsychological Society, Vol. 6 (3): 290–298.  Davelaar, E. K., Goshen-Gottstein, Y., Ashkenazi, A., Haarmann, H. J., & Usher, M. (2005). The Demise of Short-Term Memory Revisited: Empirical and Computational Investigations of Recency Effects. Psychological Review, Vol.112, 3-42. Glasser, D. M., Tsui, J. M., Pack, C. C., & Tadin, D. (2011). Perceptual and Neural Consequences of Rapid Motion Adaptation. PNAS Plus, 108(45). Howard, M. W., & Kahana, M. J. (2002). A Distributed Representation of Temporal Context. Journal of Mathematical Psychology, Vol. 46(3): 269-299. Mather, G., Verstraten, F., & Anstis, S. (1998). The Motion After Effect: A Modern Perspective. Cambridge, Mass: MIT Press Read More