The Effect Of Flicker Paradigm On Visual Perception

This study examined visual perception and the rates at which global and local features are reacted to with an aim of replicating and validating a previous experiment conducted by Navon (1977) to see if global processing was faster than local processing. There was 222 University of Newcastle students participating in the experiment, partaking in two phases, one centred round global processing, the other around local processing, where there reaction times were recorded using a computer program and imputed into a data worksheet. Results indicated that, as predicted, global processing occurred at a faster rate than local processing. It was concluded that global features were

Abrupt appearance of an object within peripheral visual fields are sudden onset distractors (SOD) and they can have effects on attention and reaction times. Attentional capture occurs when a distractor stimulus appears in a field of vision and pulls focus away from the task at hand. This has the effect of increasing reaction times as it diverts a subject’s attention while the brain registers and processes the new information. When the brain is focussed upon a specific task the distractor captures attention and thus can increase reaction time through this visual processing mechanism. This demonstrates automaticity, a reflex which is both not inhibited by increasing cognitive load (load-insensitivity criterion) and not voluntarily controlled (intentionality criterion). The attentional

Powell (1986) conducted a study in which individuals viewed a photo or slide. Individuals were required to scan images and decide on an image for the entire display (Powell, 1986). Objects were pointed to, and subjects were asked to identify its location (Powell, 1986). The subject was asked to close his or her eyes and were shown another image. The subjects were to decide if the object was in the correct position (Powell, 1986). The subjects would hear one of the objects and was required to focus on the object while keeping the entire image in his or her mind (Powell, 1986). When the next object was identified, the subjects were to move from the first object to the second watching a black dot moving in a straight line (Powell, 1986).

Luck and Vogel's change detection experiment was made to determine exactly how much information can a person withhold from a quick flash of stimulus. They modified the previous change dtetction experiment alittle. Rather than asking the person if there was a change in the display only, they also ask the person to recall the amount of items

The equipment used consisted of a 60 Hz monitor on a 19 – inch computer screen. The program for the test ran on a viglen Pentium 4.30 GHZ. To present the stimuli’s four

Researchers do differ on their perspectives on change blindness depending upon their method approach and background or field; however literature is largely in an agreed consensus as to what change blindness is and its effects on attention. Change blindness is studied by using the methodology of change detection, which is where participants are shown two stimuli that are

In previous research, it has been claimed that that ordinary perceivers operate under a grand illusion of perception, and illusion that can be unmasked by change blindness and inattentional blindness. Change blindness and inattentional blindness are phenomena relating to the inability to notice particular stimuli within our visual field, a sort of lapse in our visual system. Change blindness is when a person fails to notice a change within their visual scene because the change occurs during a moment when the intake of visual stimuli is disrupted. Similar to change blindness, inattentional blindness is characterized by the failure to notice a fully visible, but unexpected object because attention is engaged in another object, task, or event. Cohen

The participants were presented with stimuli of two components which was displayed to them on screen. One stimuli was the coloured rectangular patch (3.5x5.5cm). This patch was presented in a variety of difference colours; yellow, red, green and blue. The other stimuli that was presented to the participants was a word, which either matched up to one of the four colours, however could have been in-congruent or congruent or a natural, control 'word ' being XXXXX. As well being presented with the patch, the words would also appear, in size 24, in the centre of the patch. There were four conditions for when the word appeared; 0ms (simultaneously), 100ms, 200ms or 350ms.

The materials used in this experiment were as follows. Instructions for the participants, to be read before beginning the experiment. Informed consent forms, to be signed by participants. Response sheets to record the participant’s response for the dependant variable and a debriefing sheet to be read after the conclusion of the experiment. Two slideshows, each containing the images to be shown to each group. Each slideshow contained 20 pairs of images, shown with a three second gap and each image pair repeated five times. The slideshow was downloaded and installed onto either a desktop or laptop computer. Participants just had to watch the slideshow. Once the slideshow was finished the participants were handed a response sheet asking whether they liked the DE100 IPTV logo requiring a simple yes or no

79). They go on to mention that the reason cited most often as reason for change blindness is that the second scene overwrites the first scene, from the 2000 study from Enns & Di Lollo. Even though “people can monitor between one and four items for change”(Luck & Vogel, 1997), Treisman & Gelade in 1980 said that attention is needed to bind features to objects and Resnick (2000) said that we needed that attention to “encode a coherent representation”. Even then, Resnick says those representations are “highly volatile” can be overwritten with new information

Early studies have widely researched attention with selective processing (Driver, 2001). Broadbent (1958) filter theory of attention states that certain information does not require focal attention. It is based on certain stimulus attributes such as colour and shape (Friedenberg, 2012). A previous study carried out by Treisman and Schmidt (1982) proposes that when attention is diverted from a display of several figures, the participants incorrectly combine the features of colour and shape therefore increases the illusory conjunctions portrayed by the participants (Tsal, 1989). Another study by Shaw (1978) found that reaction time of participant to identify targets varied with the probability that a target would appear in a particular display location. These results indicate that different amounts of attention towards the targets are distributed to different positions in the visual field. However, Houck and Hoffman (1986) found that the feature integration of colour and orientation can sometimes be accomplished without attention (James et al.,

This study was a seminal replication on attention blink similar to the one done by Raymond et al, in a rapid serial visual presentation (RSVP) task. This study predicted that there would be a higher accuracy for identifying the first target, T1 and lower accuracy for the second target, T2 depending on the lag, given that T1 was accurately reported. 193 students participated in the experiment. This experiment was a part of the course requirement. There was a stream of 19 letters, each lasting for 100 ms. The target letters, T1 and/or T2, to be identified were either a ‘J’ or a ‘K’ or both from the stream of 19 letters presented. In this study, a total of 60 trials were conducted for each participant. For T1, there were 30 ‘J’ and 30 ‘K’ targets. T2 comprised of 24 J, 24 K and 12 null targets. The participants were asked to decide whether they saw the letters J, K, both or neither following the RSVP stream. They were asked to do so by using a button click mechanism. At the end of all the trials, the participants were presented with a summary of their performance report. It was observed that the percentage of T1 reported does not vary significantly as a function of lag. Also, the percentage of T2 reported varied as a function of lag. At greater lag positions, it was seen that the percentage of T2 reported goes above that of T1.

Figure 1: Mean concentrating reaction times and mean distracted reaction times of 50 Creighton University students. The mean for each condition is shown with a black X. The differences were deemed significant by the paired t-test (t = -2.8715, df = 49, p-value = 0.0060).

Change blindness and inattentional blindness are very closely related because they correspond to an individual’s ability to perceive a change or an obvious and unexpected stimulus that is in plain sight. Change blindness refers to a perceptual phenomenon where

Using the PsyCog afterimage experimental setup, we explored the effects of adaptation time and pursuit eye movements on the duration of negative afterimages. The aim for this study was to test previous claims suggesting that increases in adaptation times correspond to increases in afterimage duration and that afterimage durations are not altered with respect to pursuit eye movement. Following the analysis of the data, we determined that gradual increases in adaptation times led to subsequent increases in mean afterimage duration, along with mean afterimage durations being slightly lower for pursuit eye movements than no eye movements across all four adaptation times.