JOURNAL OF THE EXPERIMENTAL ANALYSIS OF BEHAVIOR

TECHNICAL NOTE

AN INEXPENSIVE RANDOM-ACCESS PROJECTOR FORRAPID PRESENTATION OF PICTORIAL IMAGES1

Schedule-induced attack studies with pigeons thathave utilized rear-view projected images of a conspecificas a target have employed carousel and slide-tray typeof projectors (Flory and Ellis, 1973; Rashotte, Katz,Griffin and Wright, 1975). Although these projectors,with appropriate logic circuitry (e.g., GAF ESP 2000,Kodak RA900), can provide random access to 80 to100 pictorial images, they are expensive to purchase($900 to $1025) and to maintain when used daily. Aprojection lamp with an expected life of 100 hr, forexample, costs $11.60. In addition to being bulky, noisy,and hot when continuously operated, the commerciallyavailable projectors do not provide reliable placementof the image on a screen and require a minimum ofone or more seconds between successive slide presenta-tions. This latter feature is particularly undesirable, inthat it precludes the possibility of programming achange from one stimulus to another immediately fol-lowing a specified response on a target and it eliminatesthe possibility of using the projector to simulate tar-get movement. The projector described below elimi-nates these problems and still permits instantaneousrandom access to 12 images. This is accomplished byutilizing the 12 independent optical systems from anIndustrial Electronics Engineers (Series 0080) InlineDisplay Unit.To ensure precise alignment of and convenient access

to the optical components, the lenses and socket as-sembly from a Series 0080 Inline Display Unit, wereremounted in a 9.6 by 16.0 by 21.3 cm aluminumand wood housing (Figures 1 and 2). As indicated inthese figures, the socket assembly and bulbs weremounted in holes in the rear plate and secured by twosocket assembly clips. Slots were cut in the top andbottom interior surfaces of the housing to accommodatethe lenses and opaque, black light stop, and a hingeddoor provided easy access to the projector components.For best results, the entire interior surface should bepainted flat black.Twelve, 35-mm colored positive transparencies of

a pigeon (cut to a size of approximately 1.0 by 1.5 cm)were taped to the front of condensing lens 2 andthen individually rear-view projected on a Polacoatplastic diffusing screen covered with a piece of seam-less Scotch Brand Magic transparency tape. With thisarrangement, the details of all 12 projected images were

'This research was supported in part by United StatesPublic Health Service Grants RR07143 and ROIMH25514-01 to Northeastern University. The authorsthank Jim Palmer for his technical assistance.

focused when the front of the projector was approxi-mately 24 cm from the screen. Images could be re-focused at other distances by moving the objectivelens (objective distance) and fine focusing could beaccomplished by adjusting the distance between theobjective lens and the screen (image distance). Aseparate filter for each projection cell could be mountedreadily on the light stop and a different set of 12transparencies could be projected simply by changingcondensing lens 2 on which the transparencies weremounted. The maximum usable area of each 35-mmtransparency was a circle 15 mm in diameter.The socket assembly ($3.50, part #21712-1), con-

densing lens 1 ($3.00, part #10467), condensing lens 2($3.60, part # 10468), objective lens ($2.70, part # 10469),and spring socket assembly clips ($0.30, part #14065-01)for a Series 0080 Inline Display Unit can be purchasedfrom I.E.E., Inc., 7720-40 Lemona Avenue, Van Nuys,California 91405. Total cost of the I.E.E. components,#1886 bulbs ($0.73) with an expected life of 3000 hoursat 6.3 V, and small parts for a projector is $24.00; theprojector requires approximately 3 hr to construct.The projector has been used successfully for a year

in schedule-induced attack studies in which one rear-view projected image was presented and in other studiesin which a pigeon tracked a rear-view projected imageof a conspecific between two 11.5 by 15.3 cm adjacentscreens (8.5 cm, center-to-center), each illuminated by aprojector. In this latter case, an image of a conspecificwas presented on one screen and the alternate screenwas rear-view projected with a white light. The tar-gets were matched for luminance at approximately 1ft-L and the screens were the only sources of illumina-tion in the chamber. Each attack on an image imme-diately turned it off and illuminated that screen withwhite light. Simultaneously on the adjacent screen, thewhite light was extinguished and the identical imagewas projected. Responses on a screen illuminated withwhite light had no scheduled consequence. Figure 3includes cumulative and event records for a WhiteKing pigeon concurrently exposed to a fixed-time (FT)90-sec food schedule, with a 17.5-sec protective con-tingency, and the target alternation procedure de-scribed above. Each downward deflection of the cumu-lative recorder pen corresponds to a 10-sec food delivery.In general, target responses occurred immediately afterfood removal and continued through at least one-halfof the interval. Event record "A" shows the sixth foodpresentation from that session as well as target re-sponses and changes in the position of the pictorialimage that followed that presentation. In this, as well

131

1976, 26, 131-134 NUMBER I (JULY)

TECHNICAL NOTE

Fig. 1. Photograph of random-access projector.

as in other inter-food intervals of the session, the sub-ject reliably tracked the pigeon image from side toside. The minimum time between successive targetchanges was less than 1 sec and there was an average

of fewer than one extra follow-through response on thewhite screen.

In addition to being useful for studying pictorialtarget control of schedule-induced behaviors (e.g.,

132

TECHNICAL NOTE

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134 TECHNICAL NOTE

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as a function of session time (minutes). Each downwarddeflection of the pen corresponds to a food presenta-tion. Event record "A" (below) shows the sixth foodpresentation of that session as well as the target re-sponses and changes in the position of the pictorialimage that followed that presentation.

Looney and Cohen, 1974), this inexpensive, random-access projector would be valuable for studying pic-torial control of other behaviors such as operant re-sponding (eg., Butler and Woolpy, 1963; Thompson,1964), sign-tracking, imprinted responses, and repro-ductive behavior (Lambe and Erickson, 1973).

PERRIN S. COHENBYRON C. YOBURNTHOMAS A. LOONEY2Northeastern University

REFERENCESButler, R. A. and Woolpy, J. H. Visual attention in

the rhesus monkey. Journal of Comparative andPhtysiological Psychology, 1963, 56, 324-328.

Flory, R. K. and Ellis, B. B. Schedule-induced aggres-sion against a slide-image target. Bulletin of thePsychonomic Society, 1973, 2, 287-290.

Lambe, D. R. and Erickson, C. J. Ovarian activity offemale ring dove (Streptopelia risoria) exposed tomarginal stimuli from males. Physiological Psychol-ogy, 1973, 1, 281-283.

Looney, T. A. and Cohen, P. S. Pictorial target controlof schedule-induced attack in White Carneaux pi-geons. Journal of the Experimental Analysis of Be-havior, 1974, 21, 571-584.

Rashotte, M. E., Katz, H. D., Griffin, R. W., andWright, A. C. Vocalization of White Carneauxpigeons during experiments on schedule-induced ag-gression. Journal of the Experimental Analysis ofBehavior, 1975, 23, 285-292.

Thompson, T. I. Visual reinforcement in fightingcocks. Journal of the Experimental Analysis ofBehavior, 1964, 7, 45-49.

2Now at Lynchburg College, Lynchburg, Virginia.