987,136. Recording and playback; educational appliances. J. G. GAUNT. (Thompson Ramo Wooldridge Inc.). July 13, 1962, No. 27085/62. Headings G5G and G5R. A teaching machine for exhibiting sequences of information to a person so as to educe responses from that person comprises means for receiving the person's responses and means for selecting a new sequence of information, means for storage of electrical signals representing scores assigned to a sequence of received responses and means for selecting a succeeding presentation of information on the basis of an evaluation of the stored scoring signals. The teaching machine 10, Fig. 2, is provided with a visual display device 12 including a motion picture projector having provision for showing single frames on a ground glass screen 33. The projector may be provided with means for driving the film at high speed forwardly or reversely so as to locate the required sections of the film in minimum time. Details of magnetic storage device. The aural presentation is derived from a magnetic tape storage device 14, comprising a tape 37 wound between a supply reel 38 and a take up reel 39 controlled by associated motors which are braked magnetically for rapid starting and stopping of the tape. The aural presentation to the person is made from acoustic transducers e.g. loudspeaker 47. The tape 37 has eight audio tracks, Fig. 3, co-operating with a multi-head assembly 42 having a like number of pick-up heads. The magnetic tape storage device 14 is used as a combined aural presentation and program control. The coded program information in the form of conductive segments is disposed in selected code groupings for each of the multiple tracks, these code groupings being arranged in blocks separately identified by transverse conductive strips 49. In order to sense the conductive segments split idlers 45 are held in contact with the tape 37 by adjacent pinch rollers 44. The disposition of the various segments of the group block used for programming and command functions is shown in Fig. 3. The commands in the various tracks are divided into two groups i.e. pre-response and postresponse commands separated by a space in which the tape is held stationary until the person operating the machine provides a response signal by pressing one or more of the selectively illuminated response buttons 35 on a panel 22. The use of the single responses to control the sequence of presentations is referred to as single item branching, while the use of a plurality of responses to control the sequence of presentations is referred to as multiple item branching. Accordingly two different types of code group blocks are provided in one of which the post-response commands consist of ten different commands while in the other of which the post-response commands consists of the six different commands. In each instance the pre-response commands consist of six commands. Under single item branching conditions the response signal is used to control the tape track selection directly. Under multiple item conditions the four additional commands are used to select sub-routines in accordance with the responce educed from the person. In this instance the successive responses, represented by the depression of the buttons 35 whose illumination is indicative of valid choices, are recorded in weighted relationship over a selected standard sequence. These weighted values, which are compared in scoring registers of a post-response control unit 28 with selected standard values stored on the tape are then used in selecting the next post-response track for deriving instructions as to whether the next sequence of presentation is to be used or a remedial sequence initiated before proceeding with further comparisons. Alternative storage arrangements. The audio information may also be stored on optical or magnetic stripes on the motion picture film and the coding information may be stored as recorded digital information on one or more tracks on the magnetic tape instead of by the contacting arrangements. Operation. (a) Single item branching. In single item branching operation of the machine the advanced magnetic tape storage device, 14, Fig. 1, applies the pre-response program information in the form of coded command signals to a selector unit 30, Fig. 5, including a detector 50, which provides a rectangular wave form demarcating the leading and trailing edges of the sinusoidal wave conductive segments, the trailing edges being used to actuate a pulse generator 57. The pulses generated are then counted by a counter register 53 and successively applied to decoders 52 which gate out command pulse sequences C1 to C13 on different output terminals as the information is read from the tape. The first six command pulse sequences C1. . . C6 are provided to the pre-response control unit 26 the first pair of which are used in track selection control, the fifth in response light control for the panel 22 to indicate valid selection choices and the sixth for the determination of single or multiple branch operation (Fig. 6, not shown). The seventh command signal C7 is used as a hold signal to stop the forward motion of the tape and visual display device 12 until a response is received from a response signal generator 20 or selection of a vilid choice by the buttons 35. Thereafter, the C8 to C13 command pulse sequences are directed to the post-response control unit 28 including counter registers which send signals to tape control unit 18 and visual display controlunit 16. (b) Multiple item branching. In the case of multiple item branch operation the first four C1. . . C4 pre-response command sequences are transmitted through the counter registers 60 and decoder circuit 62 (Fig. 6, not shown) of the preresponse control unit 26 into scoring registers 79 (Fig. 7, not shown) of the post-response control unit 28, where the said different weighted standard command values are successively compared with the weighted response values, contained in the different scoring registers, which then set appropriate flip-flops 80 whose signals control a switching device 43, Fig. 2, to select the appropriate pick-up head of the multi-head assembly 42. Thereafter both the magnetic tape device 14 and the visual display device 12 are rapidly moved to the selected presentations at which further selections are offered to the person, while the information necessary for the selction of the next succeeding step is assembled. Time of response to interrogation. As the selections are made by the person in response to the proffered choices, the information as to the actual selection and the time latency of the response may be recorded for independent examination in a data recorder system 24, Fig. 1, comprising a paper tape punch 92 (Fig. 9, not shown) which is responsive to response signals derived from the response signal generator 20 on depression of the button 35. The starting signal for the operation of the paper punch may be derived from the C7 hold signal from the control unit selector 30, which signal will be provided at the time the valid choices will be indicated to the person on the illuminated panel 22.