Ambiguous Animals: Mutable Mammal Biases

BirdAlys Ferragamo

Definition of an Ambiguous Figure• An ambiguous figure is an image that has multiple

possible interpretations• For example, upon first glance at the image pictured

below, one might see a vase but upon further examination the image of two people about to kiss may appear (or vice versa)

• After both interpretations have been observed the viewer might switch back and forth between the two

Prior Research

• Other scientists have shown that if the viewer is primed with contextual pictures it will influence their initial perception of the ambiguous figure

• Bugelski and Alampay (1961) found that if subjects were shown pictures of animals they were more likely to observe a rat in the “rat/man figure” and if they were shown people they were more likely to observe the man

Prior Research

• Scientists have also found that movement affects the perception of ambiguous figures

• If an ambiguous figure is moved horizontally then the observer assumes it is moving in the head direction (McBeath et. al., 1992; and Bernstein & Cooper, 1997)

Purpose and Hypothesis

• I designed my experiment to try to determine if multiple primes (picture context, movement and prior exposure to an ambiguous figure) would interfere or be additive

• I hypothesized that multiple primes would have an additive effect on the perception of an ambiguous figure.

Experimental Design• Using an animated Microsoft PowerPoint display, I

showed test subjects the two ambiguous animal figures embedded in ten other contextual animal pictures (5 context, then 1st ambiguous, 5 context, 2nd ambiguous)

• I chose to use rabbit/duck (Jastrow,1899) and swan/squirrel (Fisher, 1968) as my two ambiguous figures

• Then subjects were shown a set of instructions (pictured on next slide)

Instructions• You will see pictures of animals.• You will have 2 seconds to look at the picture and 10

seconds to answer. • Write the name or type of animal you saw.• Write one answer only in space provided

(corresponding to the number on the screen). • If you do not know the correct name you can just

write the category of animal (i.e. bird, bug, mammal)• E.g. if you see a trout but don’t know the name write

fish

This is an example of a context picture shown to test subjects.

It is the same size as the pictures that were shown, however the rest of the slide would have been blank.

Context Pictures

• To limit unwanted variables I chose context figures that were: – All black-and-white– Same number were right vs. left facing– Some were outlines and some were shaded– Headshots and full-body images

Mammals

Birds

Neutral

Example of Context Pictures

Experiments Conducted

• In order to test how picture context affected perception, I placed the two ambiguous figures within 10 other pictures of either all mammals, all neutral or all birds

• To test the movement prime I animated all the pictures to enter the screen moving face forward and then animated the ambiguous figure to move to the right so that the squirrel and rabbit were leading (and then repeated experiment with figures flipped to face/move leftward)

• Finally, I tested the effects of prior exposure to an ambiguous figure by observing the difference in how the second ambiguous figure was perceived as compared to the first one

Data

• The experiment was tested on 1,100 college-age subjects

• This provided 2,203 usable responses, as well as 33 blank or un-interpretable responses and 144 double responses (i.e. “rabbit/duck”)

The percentage of responses were significantly different in the three contexts (χ2 = 22.9, p<0.001). The picture context influenced the perception.

There was a clear bird response bias, as seen in the neutral condition (82% bird, 18% mammal). In the bird context, 100% of subjects responded bird resulting in a response ceiling, for this reason in the remaining experiments only the neutral and mammal picture contexts were used.

(N = 179)

Percentages of responses of swan and squirrel in each of the three picture contexts

The Initial Study

The following figures show:

• The results are separated for the two different ambiguous figures (as indicated by figure above graph)

• The percentage of people giving a mammal identification

• The picture context priming between neutral (white bar) and mammal (blue bar)

• The effects of prior exposure to an ambiguous figure (1st and 2nd on green backgrounds)

• The effects of movement (pink hash line bar)

The type of animal picture context clearly influenced the responses for the ambiguous figure in the first position (squirrel/swan χ2 = 12.3; rabbit/duck χ2 =11.3, p<0.001). When the previous pictures were mammals, the ambiguous figure was more commonly perceived as a mammal.

This graph shows the results of the first exposure to an ambiguous figure in stationary picture context of either mammal or neutral.

This graph shows the comparison of the results of the first and the second exposure to the ambiguous figure in stationary picture context.

When the ambiguous figure is presented second the effects of the picture priming disappear (swan/squirrel χ2 = 0.004; rabbit/duck χ2 = 0.07- no significant picture effect). Past exposure to an ambiguous figure interferes with picture priming.

This graph shows the effects of movement priming within a neutral or mammal context for the first ambiguous figure seen.

The influence of movement was not the same for the two figures (swan/squirrel χ2

= 0.1 not significant; rabbit/duck χ2 = 14.5 p<0.001). The movement priming greatly affected the rabbit/duck, however it had little impact on the swan/squirrel. The effects of picture and movement priming were additive for rabbit/duck.

This graph shows the impact of prior exposure to an ambiguous figure on the movement priming.

Previous exposure to an ambiguous figure did not decrease the impact of movement. For rabbit/duck the effects of movement priming were strong enough to overcome the interference of the previous exposure to an ambiguous figure. (in the second position : movement prime χ 2 = 36.6, p<0.001 ; picture prime in movement χ2 = 4.3 p<0.05)

ConclusionConfirming Previous Studies

• My results confirmed the picture context priming found by Bugalski and Alampay (1961). People reported more mammals when the ambiguous figure was surrounded by mammal pictures.

• McBeath et al. (1992) found that some ambiguous figures were more affected by movement priming than others. My results also confirmed this, as swan/squirrel showed no effect from movement priming but rabbit/duck had a strong prime effect.

ConclusionNovel Findings

• Previous exposure to an ambiguous figure interfered with the picture context priming. When the ambiguous figure was seen second, the mammal priming had no effect.

• When movement was effective for an ambiguous figure (rabbit/duck) then the context priming was additive. The combination of both primes resulted in a larger percentage of mammal responses.

• The effects of movement were great enough to overcome the interference of prior exposure to an ambiguous figure. For the figure that was affected by movement (rabbit/duck) the picture context priming was maintained even when seen second.

Possible Applications

• The results I found bring new information to the field of psychology about the decisions humans make when faced with ambiguity and how people respond to priming.

• My results also have possible commercial applications because the effects of priming and how to change people’s decisions are of interest to the advertising business.

Future Studies

• Ideas for possible future studies include:– Can other senses be used in priming? (e.g. if you

hear birdcalls are you more likely to see a bird?)– How do participants of different ages respond to

priming? (e.g. are young children more susceptible to the effects of priming?)

– How long do the effects of priming last? (e.g. how do subjects respond if they are primed several minutes/hours before the ambiguous figure is presented?)

References• Bernstein, L.J. and Cooper, L.A. 1997. “Direction of Motion Influences Perceptual

Identification of Ambiguous Figures.” Journal of Experimental Psychology; Human Percept.Perform. 23(3) 721-737.

• Bugelski, B.R. & Alampay, D.A. 1961. “The role of frequency in developing perceptual sets” Canadian Journal Psychology, 15(4), 205-211

• Fisher, G.H. 1968. “Ambiguity of form: Old and new” Perception&Psychophysics, 4(3), 189-192.

• Jastrow, J. 1899. “The mind’s eye” Popular Science Monthly, 54, 299-312.• McBeath, M.K., Morikawa, K. & Kaiser, M.K. 1992. “Perceptual bias for forward-facing

motion”. Psychological Science, 3(6), 362-366.

• Wotton, J.M. and Ferragamo, A.C. (2012) “Ambiguous animals: Mutable mammal biases bird” Perception, 41, 501-503.http://www.perceptionweb.com/abstract.cgi?id=p7232

Acknowledgements

• Thank you to all the students who participated in the experiments and to our colleagues in the Psychology Department at Gustavus Adolphus College who displayed the PowerPoint presentation in their classes and generously allowed us to collect data.

• Thank you to my co-author Dr. Wotton for helping me conduct this project.