Assignment 1 Guidelines: Perception Report This document provides information relating to the submission requirements and marking criteria for Assignment 1. Assessment: 30% course total Assignment Objectives: This assignment addresses the effect of a low spatial frequency grid on different orientations of the Muller-Lyer illusion. In addition to developing your knowledge in a particular area of perception, this assignment will develop your ability: • To conduct a literature search for articles that are of relevance to a specific area of research • To write sections of a manuscript for a journal publication in a format required by the APA • To express ideas clearly and concisely in a manner appropriate for a scientific report • To develop a logical argument • To arrange points in a logical order • To employ a combination of descriptive statistics, statistical significance testing, practical significance and statistical power to draw sensible conclusions from a data set • To present the crucial information in a data set effectively • To use SPSS to create a data file, specify and conduct an appropriate analysis, obtain and interpret the output Assignment Requirements (brief): a. A single title page, with Name, Student ID and Date b. The main body: no more than 6 sides A4. This should be prepared in APA 6th edition format and consist of the following: • Introduction (e.g., 1-2 sides A4): provides a brief review of the background for the project, the rationale for the research and the research hypotheses. • Results (e.g., 1-1.5 sides A4): Figures and tables should be included and described by the text. • Discussion (e.g., 1-2 sides A4): provide a summary of findings and where they fit with respect to existing theories, and directions future research might take. c. References (e.g., 1 side A4): a single page appended to the end of the main body containing the references (around 3-6 references is appropriate). Formatting of Lab Report You are required to prepare a Lab Report that closely resembles, though is not identical to, the format used for journal articles (i.e., that which meets requirements of the Australian Journal of Psychology, see above). E.g., you will notice that there is no method section required. Writing sections of journal articles provides excellent experience for producing reports and dissertations that you will encounter in years 3 and 4 of your degree. The "Lab Report Template" document on Blackboard provides all the formatting required for this assignment. Submission: To Turnitin by Friday 23rd September at 4:30pm (Upload times will be treated as final) Background to the assignment: To assist you in getting to grips with the themes (which are often complex), I have included some background information for this experiment – this should help get you oriented, but to be thorough, you will also need to read and make reference to other work. In geometric illusions, the spatial relationships between components of the visual scene are perceived incorrectly; that is, perceptual experience does not match sensory stimulation. The Muller Lyer illusion (Figure 1) is one such example, typically consisting of two lines presented together, one with inward facing arrows and one with outward facing arrows. In some versions of this task, observers are required to adjust one of the arrows so that the parallel lines are equal length. Most people typically perceive the distance between the inward pointing arrows as approximately 20% longer than the distance between the outward pointing arrows. (a) (b) Figure 1. A classical presentation of the Muller-Lyer illusion (a), and the Brentano form of the illusion (b). The connecting line in the top image, with the outward pointing arrows is typically perceived as being shorter than that of the bottom image, despite being equal length in actuality. A number of theories for the existence of this illusion have been proposed: The perspective explanation: One explanation for this illusion is that the visual system perceives angled arrows to be representative of depth cues. Gregory (1966) calls this 'misapplied size constancy scaling'. Although size constancy usually helps us maintain stable size perceptions by taking distance cues (such as edge angles) into account, these same cues create an illusory experience in the case of the Muller-Lyer illusion. There are limitations to Gregory's theory though. The illusion still seems to occur for actual 3D displays (such as open books adjusted across a line on the floor) and for the 'dumbbell' version of the illusion, which contains no apparent depth cues. The spatial frequency explanation: Carrasco, Figueroa, and Willen (1986) provide a reasonable overview of this perspective in their introduction. We will cover the theory underlying this argument in the lectures on the visual system. The central argument is that "our ability to process stimuli in a rapid and global manner depends primarily on simple filtering of relevant spatial information for particular tasks" (p. 553). So the visual system (according to this argument) deconstructs the frequency variations in an image before processing edges and other features. The reason an illusory experience occurs for the Muller-Lyer illusion then, is because the two variations are in fact physically different lengths when viewed as a low-pass filtered image. Essentially, this is a 'bottom-up' perspective, since it is argued that the processing of sensory data (different spatial frequencies) is the most important determinant of perceptual experience. A key strength of this theory is that it provides an explanation for the dumbbell and 3D presentations of the Muller-Lyer illusion. Carrasco and colleagues presented the Brentano form of the Muller-Lyer illusion (with varying arrow angles) to eight participants, requiring them to adjust the length of the central fin both before and after viewing a vertical spatial frequency grating (low/high frequency gratings used separately on consecutive days for each participant). The magnitude of the illusion significantly reduced for all variations of the illusion after exposure to a low spatial frequency grid. There was no change in illusion magnitude after exposure to a high frequency grating though. Carrasco and colleagues followed this up with an identical experiment using horizontal gratings instead of vertical gratings. Not surprisingly, there was no significant difference in pre- and post-test illusion magnitude. This can be explained in terms of selective adaptation. Neurons at different levels of the visual system are sensitive to very specific object features such as specific locations, orientations, lengths, shapes, and so on. Selective adaptation occurs when an individual is exposed to a stimulus until the associated 'feature detection' neurons are 'tired out'. So for example, asking someone to scan up and down a spatial frequency grating will cause neurons sensitive to both that frequency and orientation to tire. Since all cells have a baseline level of activity, tiring them out will reduce a person's sensitivity to those features until the cells recover. When exposed to a vertical grating, Carrasco and colleagues' participants become less sensitive to the illusion (indicated by a significant reduction in magnitude). Since vertical gratings vary in brightness across the horizontal plane, it stands to reason that tiring these cells will reduce the impact of the illusion when presented horizontally, which is what they found. Additionally, the reduction in illusion magnitude after exposure to a low frequency grating but not when exposed to a high frequency grating seems to indicate that low spatial frequencies are important in producing the Muller-Lyer illusion. Evidence contradicting the spatial frequency explanation: Very few studies have adequately tested this explanation for the Muller-Lyer illusion. Carlson, Moeller, and Anderson (1984) assessed the Muller-Lyer illusion magnitude in six subjects (no selection/demographic data provided). The illusion was presented in two forms (see Figure 2), each of which was displayed three times. Task ordering was randomised and participants were given as much time as they needed to decide which of the two lines was longer. Results indicated no difference in illusion magnitude for the two forms of the illusion, and Carlson and colleagues concluded that the Muller-Lyer illusion is therefore not created by the presence of low spatial frequencies in the illusion presentation. Interpretation of non-significance is this study remains dubious at best though, since the severely restricted power level may have limited the detection of a significant illusion effect. Moreover, the forced choice nature of the task does not allow graded measurement of illusory effects. (a) (b) Figure 2. Muller-Lyer illusions constructed from: (a) white dots on a black background containing a range of spatial frequencies and peaking in the low range; (b) a 'balanced dot' version of (a) containing no visible low spatial frequencies, in which the white dots are surrounded by dark rings so that the average luminance of the dots and grey background are equal. What we have done in our experiment: A repeated measures experimental design with random allocation of condition was used to investigate the effect of a low spatial frequency grid on three different orientations of the Muller-Lyer illusion. The main task was to adjust the length of one line until the lines were perceived to be of equal length. In Part 1, this was performed for three orientations. Part 2 presented the same conditions, but included the spatial frequency grid. Thus our independent variable was Orientation (horizontal, vertical, and diagonal). The order of illusion presentation was randomly assigned to participants. Participants conducted the experiment independently of each other. The dependent variable in the study was Difference (in pixels) between the Muller-Lyer presented and the adjustable line. This can thus be looked at in these 2 ways: (1) across Condition (Pre-Grating) to see if there were any differences in perception of the illusion at each orientation before the spatial frequency grids, (2) across Condition, but using the difference between Pre and Post Grating to test whether the spatial frequency grid had any effect on perception of the Muller-Lyer illusion. Why stare at grids? Summarising what has been discussed so far: We have cells that are dedicated to analysing different spatial frequencies. Some cells just respond to the low spatial frequency features of an image and other cells are dedicated to analysing the high spatial frequency features of the image (note: there are many different cells for many different spatial frequencies). How do we knock out those particular cells? Nowadays we are not allowed to perform surgery on our students, even for laboratory classes. However, we can tire out (exhaust) those cells, making them effectively shut down. We do this by getting the participant to stare at a low frequency grid for an extended period of time. THE CENTRAL ARGUMENT: If the Muller-Lyer illusion is produced by low spatial frequency components of the visual scene, knocking out the low frequency cells should reduce the magnitude of the illusion. Example Hypotheses: (You can use these, or your own providing the data exists to test them!) H1: Orientation will not significantly impact the perception of line length (Note: one only needs to include Pre-Horizontal, Pre-Diagonal and Pre-Vertical to answer this question - The argument behind this is that different orientations do not impact the strength of firing, they only affect which neurons are 'doing the firing'.) H2: There will be a significant relationship between orientation and pre/post-test difference scores such that the horizontal illusion will show the greatest reduction in magnitude (the reasoning here, is that the horizontal spatial frequency grid will have greatest effect (if any at all) on the horizontal condition). You might choose to word this differently and test for differences on e.g., vertical or diagonal. Task: You are required to analyse and interpret the data set and then write up the Introduction, Results and Discussion sections for this experiment. You must also include an APA formatted title page with an appropriate heading for the paper (as though you were going to submit it for publication) and a reference list for any sources you cite in your Discussion. There is a Lab Report Template on Blackboard available for this purpose. The data file: A data file (SPSS .sav file) will be released on Blackboard.   Requirements for your report Your perception report is a formal document and must conform to the guidelines for content, style and organisation given in the APA Publication Manual (6th edition). APA format is the required standard for formal communication between professionals in the field of psychology. Failure to write a report that conforms to APA format will give the impression that you are also not likely to show due regard to the basic standards of scientific research. Familiarity with the guidelines for content, style and organisation given in the APA Publication Manual will be crucial to your future professional success. Sections of the report that are required and the allocation of marks 1. Title Page (5 marks) 2. Introduction (10 marks) 3. Results (10 marks) 4. Discussion (10 marks) 5. References (5 marks) 6. Coherence and presentation (10 marks) TOTAL: 50 marks Each section of the lab report has its specific requirements and information that must be supplied. These are set out on the following pages.   APA Research Report Requirements This report checklist has been compiled with reference to the APA publication manual. Before we look at the specific sections of the report here are some general pointers. GENERAL STYLE AND PRESENTATION Have you arranged points in logical order, with one point flowing logically on to the next? Is the expression of arguments logical and competent? Have you supported all arguments/statements with evidence? Is expression clear and concise throughout the report? Is the report written in an 'objective' style? Is the research report tidily presented? Are there any unnecessary abbreviations? Have necessary abbreviations been explained? Have you avoided using slang? Have you checked for grammatical errors? Have you checked for spelling mistakes? PARAGRAPHS AND HEADINGS Is each paragraph longer than a single sentence? Is each paragraph not longer than one manuscript page? Do the levels of headings accurately reflect the organisation of the research report? Is the first line of every paragraph indented (except block quotations, titles and headings, table titles, figure captions)? EXPRESSION Have you said only what needs to be said? Have you been frugal with words? Have you eliminated all redundancy? You do not need to include: "When doing his research Smith (2005) showed…." Have you eliminated wordiness? Do you need to say "At the present time.." when "now" would do Have you eliminated evasiveness? Have you made sure you have not overused the passive voice? The passive voice makes an article overly wordy (and difficult to read) For example: Compare: It is through this research that I hope to examine the effects of … on ….. With: This research will examine the effects of … on ….. Students often begin sentences with "This is also found when..", "It can be shown that.." "It can be seen that.. " and so on. If you find you are doing this, you are using the passive voice. Have you eliminated circumlocution? Have you eliminated clumsy prose? Have you eliminated gratuitous embellishments? (E.g., "A very interesting exceptional piece of research by…") Have you eliminated elaborations of the obvious? ("the light was switched on to illuminate the room") Have you eliminated irrelevant observations or asides? ("The author, who also enjoyed a bit of a drink ..") Have you used words precisely? (i.e., do not substitute 'feel' for 'think' or 'believe') Have you eliminated avoided approximations of quantity? (avoid, for example, "nearly all", "very few") Have you avoided using pronouns (this, that, these) when the referent is not obvious? Have you eliminated ambiguous comparisons? (Figure out this sentence: Third year students are more likely to talk to lecturers than second year students.) Have you said what you meant to say? We often know what you meant to say but in a scientific communication your language must be precise. An example of a badly worded argument: "Our enemies are innovative and resourceful, and so are we. They never stop thinking about new ways to harm our country and our people, and neither do we" George Bush Have you eliminated illogical comparisons? "Your writing is worse than a first year student" Have you eliminated anthropomorphism? Do not attribute human characteristics to inanimate sources (i.e., an experiment does not attempt to demonstrate…) Have you used the editorial we appropriately? Restrict 'we' to refer to yourself and your co-authors unless the referent is clear. Do not state, for example, "We are often bewildered by illusions". This is interpreted as a statement about you and your co-workers. Leedy (1993) offers the following guidelines for clear writing: 1. Express the thought fully with the least words possible 2. Use a thesaurus: It will help you find the exact word (Note: DO NOT insert words you do not understand. A synonym does not necessarily have the same meaning) 3. Never use a long word where a short one will do. Attempt to use one- or two-syllable words rather than longer ones. 4. Keep your sentences short. Vary the length, of course, but break up those long, contorted sentences into shorter, more succinct ones. 5. Look critically at each thought as it stands on the paper. Do the words say exactly what you wish them to say? Read carefully phrase by phrase. See if one word will carry the burden of two or more. Throw out superfluous words. 6. Be alert to modification. Misplaced phrases and clauses can create havoc with the thought. NUMBERS Use figures for the number 10 and above Use words for numbers below 10 However, use figures for all numbers below 10 that are grouped for comparison with numbers 10 and above Also use figures for all numbers that immediately precede a unit of measurement Use figures for numbers that represent statistical or mathematical functions Use figures for numbers that represent time, dates, ages; sample, sub sample, or population size; numbers of participants in an experiment; scores and points on a scale; numerals as numerals Use figures to denote a specific place in a numbered series Use numbers in the abstract of the paper Use roman numerals when it is established terminology (e.g., type II) Do not use apostrophes for plurals of numbers Use a zero before the decimal point when numbers are less than 1 BUT do not use a zero when the number cannot be greater than 1 (e.g., correlation coefficient)   SPECIFIC SECTIONS Writing Style You are encouraged to write in the active voice. For example, "We gave our participants the WET test" is better than "The participants were given the WET test". Use of the pronoun "I" or "we" is encouraged where it is appropriate and where it improves writing style. Formatting Please ensure that your work conforms to APA (6th ed.) formatting as appropriate for the Australian Journal of Psychology. Some guidelines of the requirements for each section are provided below, but please also read the relevant sections of the APA manual (6th ed.) for further information. The Title The title should reflect what was done in the study. It should contain the key variables that are reported on and any variables that were manipulated. The title page should include a Title, Name, Student ID and Date (see the Lab Report Template document on Blackboard) The Introduction The purpose of the introduction is to introduce the problem your study aims to address, establish why further research is important, review relevant literature and provide the research question/objectives/hypotheses. 1. A funnel structure is often appropriate. Start with more general aspects of the topic and become more specific as you go along. 2. It may be useful to have an initial statement stating the specific purpose of your introduction and a brief 'roadmap' to the introduction/article. 3. The review of literature should include critical evaluation of the relevant research, of relevant theories (if they exist), and justification of the methodology you are going to use. The Results Section The purpose of the results section is to present the evidence (data, statistics) to evaluate the propositions developed in the introduction (i.e. to test your). Please begin by including descriptive statistics before moving to hypothesis testing. It is important to describe in words what the statistics show. Helping the reader to understand what you have found is just as important as the statistics themselves. Highlight the important information that you will address in the discussion. Please ensure that you use APA (6th ed.) style and formatting for tables and graphs. The Discussion Section The purpose of the discussion section is to evaluate the evidence gathered and interpret your findings. This involves accepting, reject or modifying your initial proposition (hypotheses) and reaching a conclusion to the argument that you have developed. Your discussion may include: 1. Summary of main findings, and status of hypotheses. 2. Interpretation of the results. Why did you find what you did find? Go back to the information in the introduction for explanations. If you have based your study on a particular theory, is it supported or not? If not is there a viable alternative? 3. If something unexpected has been found, you can introduce new material (references) to discuss. 4. Were there any limitations of the study (methodological, other concerns or events) that may have affected the outcome? 5. Future directions for research: improvements to your study, logical extensions. 6. Practical applications and theoretical implications. 7. A concluding statement, summing up the outcome of your argument The Reference Section Numerous references will be made available via Blackboard / E-reserve site for this unit. Part of your assignment is to choose those that are relevant and reference these appropriately. Submitting your Lab Report Please submit: • One electronic copy of your Lab Report to Turnitin, via the link on blackboard, before the specified deadline. MARKING SHEET Section of Lab Report Fail Inadequate Barely Adequate Adequate Good Very Good Excellent Title Title unclear. Incomplete, incorrectly formatted page, missing Name and/or Student ID and/or Date. (0 points) Barely adequate title page, either confusing title and/or poor formatting. (1 point) Good clear title, only minor formatting issues. (3 points) Very good title page. Clear title, no errors in formatting. (5 points) Introduction Inadequate literature review devoid of critical evaluation demonstrating limited comprehension of relevant theory/research. Inadequate rationale and hypotheses. (0 points) Barely adequate literature review with poorly stated rationale and hypotheses. (2 points) A limited literature review that requires further work to develop the rationale and hypotheses for the study. (4 points) Good literature review with limited critical analysis and/or limited development of rationale and hypotheses. (6 points) Well written, comprehensive, critical, integrated review. Well formulated rationale and hypotheses. Contains only minor errors or omissions. (8 points) Well written, comprehensive, critical, integrated review. Well formulated rationale and hypotheses. (10 points) Results Inadequate results section demonstrating a lack of understanding of analyses. (0 points) Barely adequate results section with multiple errors or omissions. (2 points) Adequate results section that requires further work in analysis and/or description. (4 points) Good results section with some errors or omissions requiring attention. (6 points) Well presented, comprehensive results section with only minor errors or omissions. (8 points) Well presented, comprehensive results section. (10 points) Section of Lab Report Fail (< 50) Inadequate 3rd Class (50‐59) Barely Adequate 2B (60‐69) Adequate 2A (70‐79) Good First (80‐89) Very Good First (90‐99) Excellent Discussion Inadequate discussion that fails to integrate the results in the context of the extant literature. (0 points) Barely adequate discussion requiring substantial work to demonstrate understanding of the study in the context of the extant literature. (2 points) Adequate discussion with limited understanding of the study in the context of the extant literature. (4 points) Good discussion demonstrating a reasonable understanding of the study in the context of the extant literature. Some areas could benefit from further development. (6 points) Well presented, comprehensive, integrated discussion demonstrating understanding of study in context of extant literature. Only minor errors or omissions. (8 points) Well presented, comprehensive, integrated discussion demonstrating thorough understanding of study in context of extant literature. (10 points) References Inadequate use of references and citations. Multiple errors/ omissions. (0 points) Some references correctly used but multiples errors, incomplete references. (1 point) Reasonably well presented references, though containing several minor errors in APA. (3 points) Excellent referencing throughout, adherence to APA style. (5 points) Coherence and Presentation Inadequate presentation with poor level of written expression, overall lack of coherence, poor adherence to APA style and major errors/ omissions. (0 points) Barely adequate presentation with deficits in overall coherence and written expression, limited and poor adherence to APA style. (2 points) Adequate presentation with limited coherence and clarity and some major errors or omission in APA style. (4 points) Reasonably well written. Good presentation with several minor errors in APA. (6 points) Well written, coherent, in APA style. Only minor errors or omissions in style or content. (8 points) Well written, coherent, Excellent adherence to APA style. (10 points)