Perception Lab Reports Style Guide Aaron Bornstein - aaronb@nyu.edu 09.23.2008
Introduction - Goals Motivate the study What is this illusion / effect, what might it say about basic perception? Motivate the hypotheses What aspects are you manipulating? Why did you choose those? What do you expect? High-level description of how to test each hypothesis One or two sentence description of what your experiment does.
Introduction Examples Motivate the study The Mueller-Lyer Illusion is the effect created when... This implies that the human visual system is designed to... Motivate the hypotheses Besides line orientation, the visual system may be specifically sensitive to the number of polka dots on a stimulus line... It is possible that further modulation of the Mueller-Lyer effect is possible by manipulating the number of polka dots... We expect that these manipulations will affect performance in the task by... High-level description of how to test each hypothesis To test this hypothesis, we varied the number of polka dots in the following ways...
Methods - Goals Describe all relevant features of stimuli What did you control for? (ie: Luminance, Contrast, Size, Features) What did you vary? How much? Step-by-step of observer's experience What measurements did you take? Replication is the goal
Methods - Examples Describe all relevant features of stimuli Stimuli were white lines in one of ten randomly chosen lengths, each presented at screen center against a black background. Each length stimulus [a,b,c,...] was presented three times each with varying numbers of polka dots [x,y,z,...] Step-by-step of observer's experience All observers were first presented with a white line, measuring 100 pixels, designated as the 'standard' against which all other stimuli were to be measured... The ensuing stimulus was not presented until a response was entered... What measurements did you take? Responses consisted of numerical estimates of the length of the line, relative to the standard... Reaction times were collected...
Results - Goals Explicitly state the results of each test Refer to your graphs directly and explain them Claims about data should be quantified How do you know it's (not)significant? Use tables sparingly Lists of numbers are harder to interpret than graphs
Results - Examples Explicitly state the results of each test Polka dot densities above X resulted in a positive change in the estimated length of a line as compared to estimates at arrow angles of zero degrees (mean difference Y, standard error Z). Refer to your graphs directly and explain them Figure A illustrates the effect of polka dot number on response estimate. Figure B illustrates the effect of polka dot size... Line length correlated highly with response estimates, as illustrated in Figure Y Claims about data should be quantified Measure A (mean 25, standard error 2) is significantly greater than Measure B (mean 2, standard error 1).
Discussion - Goals Explain how your hypotheses were (or were not) validated Refer to specific results Give a few succinct sentences about the broader implications, if any Optional: Suggest further work
Discussion - Examples Explain how your hypotheses were (or were not) validated We expected that adding polka dots to the stimulus lines would increase length judgements. Our results demonstrate that individuals presented with increasing numbers of polka dots in fact estimate lines to be of shorter lengths... Give a few succinct sentences about the broader implications, if any Our results imply that the visual system is capable of compensating for changes in polka dot-ness, a finding that corresponds with accounts of vision as specially attuned for polka dot-enriched worlds. Optional: Suggest further work Further studies along these lines may be necessary to test the effect of embedding polka dots inside the polka dots.
In General... Write so it can be read Use narratives, not lists In Methods/Results, write in the passive, past tense stimuli were shown... data were collected Make specific, well-supported claims Every assertion should follow directly from data Illustrate your points Use graphs, figures, examples